Abstracts

Title: Where do we go from here? Mitigating harmful cyanobacterial blooms in large lake ecosystems facing nutrient over-enrichment and climate change

Speaker: Hans W. Paerl

Authors: Hans W. Paerl, Malcolm A. Barnard, Haley E. Plaas, Karen L. Rossignol, Amy N. Bartenfelder, Justin D Chaffin, Steven W Wilhelm, Thomas B. Bridgeman, George S. Bullerjahn and Timothy W. Davis

Abstract: Harmful (toxic, hypoxia-generating, food web altering) cyanobacterial blooms (CyanoHABs) pose a serious environmental and human health problem that is expanding globally and threatening the sustainability of aquatic ecosystems, including some of the world’s largest lakes. Human-induced nutrient enrichment and hydrologic modifications, including dam and reservoir construction and diversions, are a major driver of bloom expansion. Other drivers of bloom expansion stem from climate changes including warming, more extreme rainfall and drought events. These events act synergistically with man-made drivers to exacerbate the problem. Bloom mitigation steps must incorporate these dynamic interactive factors to be successful in the short- and long-term. To be most effective, these steps must be applicable along the large lake to coastal continuum. Nutrient input reductions are an essential component of virtually all CyanoHAB mitigation strategies. Traditionally, phosphorus (P) reductions were prescribed for freshwater systems, while (N) reductions were stressed in brackish and coastal waters. However, these systems are hydrologically connected and on the watershed scale single nutrient (e.g., P) management steps taken upstream may not reduce CyanoHAB problems and sometimes exacerbate them downstream. To ensure long term, sustainable success, these strategies should include both N and P input reductions. Nutrient input reductions that incorporate hydrologic changes and extremes are needed along the continuum as an integral component of nutrient management because as human and climatic pressures change, and internal nutrient cycling loading varies over time, new nutrient-bloom thresholds will likely emerge. Examples of the interactive pressures of anthropogenic nutrient enrichment and changing climatic (temperature, precipitation and wind) regimes influencing bloom thresholds are discussed for CyanoHAB impacting large Lakes Erie (US-Canada), Okeechobee (Florida), and Taihu (China).

Title: Developing a predictive understanding of harmful cyanobacteria growth, toxin production and comparative toxicity across environmental gradients

Speaker: Bryan Brooks

Abstract: The extent to which climate change and stoichiometric interactions between N and P, particularly in combination with salinity, influence the growth, toxins production and toxicity of cyanobacteria harmful algal blooms (HAB) remains poorly understood. Though ecological studies and monitoring activities have examined various measures of “toxicity,” these efforts are routinely limited by absence of toxins determination and comparative toxicity information related to water quality risks to human health and the environment. Because inconsistent approaches have been employed to quantify cyanotoxins, we employ targeted and nontargeted analytical methods for quantitation of cyanotoxins in aquatic systems, and during laboratory experiments with cyanobacteria across environmental gradients and toxicology studies. We are engaging these major research needs towards developing an advanced understanding of cyanoHAB risks to water quality, which we are examining through mechanistic studies of proteomic, transcriptomic and behavioral pattern responses in the zebrafish and fathead minnow models for specific cyanotoxins and cyanobacteria. Further, commonly used water quality models lack inputs for toxins production, which inherently limits predictive capacity of HAB events. Some species of cyanobacteria have evolved unique adaptations to promote their growth under N-deficient conditions, but has remained poorly understood whether or not these traits actively exist simultaneously with toxins production. However, we identify N availability, relative to P and light, provides a dual regulatory mechanism that controls both biomass production and cellular synthesis of microcystin-LR. We further continue to examine production dynamics of cylindrospermopsin and anatoxins producing species. More broadly, at the request from State of Texas agency staff, we have been supporting water resource managers and public health practitioners to assess cyanoHAB events and to support decisions for Texas lakes, which provide potable water supplies, fisheries and recreational uses. Our project team’s efforts developing predictive growth, toxins production and comparative toxicity models for cyanobacteria promises to improve forecasting, diagnosing and preventing of wildlife and human health risks of importance to local communities.

Title: The influence of nutrients on Microcystis physiology and proliferation: Are viruses part of your “bottle effects”?

Speaker: Helena L. Pound

Authors: Helena L. Pound, Robbie M. Martin, Brittany N. Zepernick, Courtney J. Christopher, Sara M. Howard, Hector Castro, Shawn R. Campagna, Gregory L. Boyer, George S. Bullerjahn, Justin D. Chaffin and Steven W. Wilhelm

Abstract: Environmental conditions of natural microbial communities are rarely fully simulated in the laboratory. Many researchers use experimental containers (“bottles”), where natural samples can be manipulated and evaluated. However, container-based methods are subject to “bottle effects”, changes that occur when simply enclosing microbial community. We noted variability consistent with these phenomena in a short-term, nutrient amendment experiment during a 2019 Lake Erie Microcystis bloom. We observed community activity (transcription) in heterotrophic bacteria in a time-frame consistent with a response linked to changes in nutrient availability, and not to changes in phototroph activity, demonstrating how the often overlooked microbiome of cyanobacterial blooms can be altered. T0 samples showed high expression of Bacteroidetes, which was reduced in all bottles - including controls - after 48 hours. Significant biological variability was also observed between replicates in the expression of Microcystis-infecting phage, with phosphate amended replicates showing a 10-fold variation. These phage expression patterns were correlated with ~35% of Microcystis spp. functional genes and ~45% of the cellular-metabolites measured across the entire microbial community, suggesting they not only influence Microcystis dynamics, but the entire microbiome. Our observations demonstrate the influence of bottle effects yet show they can be harnessed to provide insight on biological variability.

Kirstein, I. V., S. Kirmizi, A. Wichels, A. Garin-Fernandez, R. Erler, M. Löder and G. Gerdts (2016). "Dangerous hitchhikers? Evidence for potentially pathogenic Vibrio spp. on microplastic particles." Marine Environmental Research 120: 1-8

Bowley, J., C. Baker-Austin, A. Porter, R. Hartnell and C. Lewis (2021). "Oceanic Hitchhikers – Assessing Pathogen Risks from Marine Microplastic." Trends in Microbiology 29(2): 107-116

Title: Comparison of HAB microbial communities in Sandusky Bay, Lake Erie from 2018 and 2019

Speaker: Michelle Neudeck

Authors: Michelle Neudeck, R. Michael McKay, George S. Bullerjahn

Abstract: Cyanobacterial Harmful Algal Blooms have been occurring in Sandusky Bay, Lake Erie since the early 2000’s. Typically these have been dominated by Planktothrix agardhii. This has been attributed to the ability of P. agardhii to adapt to nitrogen limitation of the bay due to high rates of sedimentary denitrification (Salk et al. 2018, Hampel et al. 2019). These blooms persist from May until October and produce the toxin microcystin in varying amounts. Nine sites in Sandusky Bay were sampled every two weeks during the summers of 2018 and 2019. Sequencing of the 16S rRNA genes from the 2018 and 2019 samples reveal that 2018 was predominantly Planktothrix, except for the Inner Bay in the middle of June, which was not dominated by cyanobacteria. This coincided with an increase in nitrate levels and soluble reactive phosphorus. The sampling of 2019 demonstrates a greater diversity of the microbial community. There were periods of Planktothrix abundance in the beginning of June and late September, but the middle of June to September shows a broad mixture in the community. At the June 19, 2019, sampling, levels of nitrate and dissolved phosphorus showed an increase that coincided with a decline in Planktothrix abundance. There is also a decline of microcystin production. The changes in community may be a result of the removal of the Ballville Dam on the Sandusky River at the end of August in 2018. Since sedimentary internal loading has been a major source of phosphorus for the bloom in prior years, dam removal may have mobilized nutrient-poor sediments into Sandusky Bay. Another contributing factor could be the rains during the Spring of 2019 which disrupted 90% of the agricultural activity in the northwestern portion of Ohio for the season. Future chemical analysis of archived sediment samples will help assess the extent to which dam removal has contributed to changes in internal loading of nutrients.

References:

Salk, K. R., G.S. Bullerjahn, R.M.L. McKay, J.D. Chaffin, and N.E. Ostrom. 2018. Nitrogen cycling in Sandusky Bay, Lake Erie: Oscillations between strong and weak export and implications for harmful algal blooms, Biogeosciences 15: 2891–2907.

Hampel, J., M.J. McCarthy, M. Neudeck, G.S. Bullerjahn, R.M. McKay and S.E. Newell. 2019. Ammonium recycling supports toxic Planktothrix blooms in Sandusky Bay, Lake Erie: evidence from stable isotope and metatranscriptome data. Harmful Algae 81: 42-52.

Title:

Presenter: Hannah Sims

Abstract: Ciguatera Poisoning (CP) is a foodborne illness associated with seafood consumption from tropical areas. Tens of thousands of people are afflicted with CP each year and the distribution of this illness is increasing worldwide. CP is caused by ciguatoxin, the precursors of which are produced by some members of the benthic dinoflagellate genus, Gambierdiscus, and possibly other compounds produced by other co-occurring dinoflagellates which inhabit dead coral surfaces and benthic macroalgae. The toxins accumulate in the tissues of fish that eat the macroalgae and are transferred up the food chain. As climate change increases sea surface temperatures (SST) and impacts coral reefs, the habitat of toxic dinoflagellates (macroalgae) could potentially expand, increasing cases of CP worldwide. As a follow up to the pioneering work of Bomber (1985), a study was designed to assess the abundance of Gambierdiscus and co-occurring benthic dinoflagellates in the Florida Keys, to determine if they have increased over the past four decades. The dinoflagellates and associated environmental parameters are being monitored over a 14-month period using four of the same locations and time points utilized by Bomber (1985). It is predicted that dinoflagellate densities will have increased, due to environmental changes over the past 40+ years. The current status of the project will be presented herein.

Title: Evaluating FluoroProbe as a tool for rapid chlorophyll a and phytoplankton group differentiation during bloom conditions

Presenter: Malcolm Barnard

Authors: Malcolm A. Barnard, Haley E. Plaas, Karen L. Rossignol, Jeremy S. Braddy, Amy N. Bartenfelder, Justin D. Chaffin, Robbie M. Martin, David J. Niknejad, Steven W. Wilhelm, and Hans W. Paerl

Abstract: With global proliferation of CyanoHABs, there is an immediate need for rapid detection, quantification, and determination of their composition to evaluate potential threats to public health. One method of rapid detection of bloom size and composition is the FluoroProbe, which uses in situ fluorimetry to determine phytoplankton biomass (as chlorophyll a, chla) and community composition (as chla by group). We compared FluoroProbe analyses with more time-consuming and expensive pigment extraction-based methodologies. As with other in situ fluorometric methods, there is a maximum limit of accuracy due to fluorescence signal quenching. To evaluate the efficacy of FluoroProbes while studying bloom conditions in bottle experiments, we examined the correlations between extracted pigment analysis (chla and community composition) and FluoroProbe group-specific chla and community composition analysis from Maumee Bay and Sandusky Bay (Lake Erie, OH, USA) bottle experimentsin June and August, 2019 and August, 2021. Across experiments, total chla ranged from < 10 μg/L to > 400 μg/L. Total chla produced similar results (R2 > 0.75) between FluoroProbe and extraction methods. However, community composition as measured by the FluoroProbe differed from that determined by HPLC-based CHEMTAX diagnostic photo-pigment analysis. In this case, the FluoroProbe was directly comparable to extraction methods for cyanobacteria and cryptophytes (R2 > 0.8) but produced different results from diatoms and chlorophytes, (R2 < 0.5). This comparison will be complemented using FlowCam analysis for the August 2021 data to evaluate which method more closely follows community composition. We conclude the Fluoroprobe and extraction methodology are comparable for chla analysis, but less so for community composition for use in microcosm/mesocosm experiments of highly productive systems.

Title: Transcriptomic analysis reveals that municipal wastewater effluent enhances Vibrio vulnificus growth and virulence potential

Presenter: Karlen E. Correa Velez

Authors: Karlen E. Correa Velez and R. Sean Norman

Abstract: Vibrio vulnificus is an opportunistic pathogen indigenous to estuarine and marine environments and associated with aquatic organisms. V. vulnificus is of utmost importance because it causes 95% of the seafood-related deaths in the US due to rapid progression of septicemia. Changes in environmental parameters associated with climate change and coastal population expansion are altering geographical constraints, resulting in increased Vibrio spread, exposure, and rates of infection. In addition, coastal population expansion is resulting in increased input of treated municipal sewage into areas that are also experiencing increased Vibrio proliferation. This study aimed to better understand the influence of treated sewage effluent on effluent-receiving microbial communities using Vibrio as a model of an opportunistic pathogen. Integrated transcriptomic approaches were used to analyze the changes in overall gene expression of V. vulnificus NBRC 15645 exposed to wastewater treatment plant (WWTP) effluent for a period of six hours using a modified seawater yeast extract media that contained 0%, 50%, and 100% filtered WWTP effluent. RNA-seq reads were mapped, annotated, and analyzed to identify differentially expressed genes using the Pathosystems Resource Integration Center analysis tool. The study revealed that V. vulnificus responds to wastewater effluent exposure by activating cyclic di-GMP-influenced biofilm development. Also, genes involved in crucial functions, such as nitrogen metabolism and bacterial attachment, were upregulated depending on the presence of treated municipal sewage (Figure 1). This altered gene expression increased V. vulnificus growth and proliferation and enhanced genes and pathways involved in bacterial survival during the early stages of infection in a host. These factors represent a potential public health risk due to exposure to environmental reservoirs of potentially Vibrio strains with enhanced virulence profiles in coastal areas.

Title: Environmental surveillance of Vibrio parahaemolyticus and Vibrio vulnificus in Chesapeake Bay Water and Oysters

Presenter: Kyle D. Brumfield

Authors: Kyle D. Brumfield, Mayank Gangwar, Moiz Usmani, Antarpreet Jutla, Rita R. Colwell and Anwar Huq

Abstract: Pathogenic Vibrio spp., e.g., Vibrio parahaemolyticus (Vp) and Vibrio vulnificus (Vv), cause gastroenteritis, septicemia, and other extra-intestinal infections. Because of the affinity of Vibrio spp., in general, for warm water of low salinity, a capability to grow in and on appropriate hosts, and broad pathogenicity profile, they have been proposed as a useful environmental indicator of climate change [1,2]. Several studies have documented a pattern of poleward spreading of Vibrio spp., demonstrating significant geographic expansion of Vibrio populations, correlated with impact on human health and rise in the number of Vibrio infections [1–3]. Vp is the leading cause of bacterial gastroenteritis associated with seafood consumption and is responsible for over 45,000 illnesses each year in the United States [4]. Vv is one of the deadliest water-borne pathogens, with a fatality rate greater than 50% for primary septicemia, and is responsible for ca. 95% of all waterborne and seafood-related deaths in the U.S. [5]. Vp and Vv are ecologically significant aquatic bacteria that cannot be eradicated from the environment and are readily isolated from water and shellfish when appropriate techniques are used. Routine surveillance for Vibrio spp. and environmental conditions that impact their incidence can be used to design predictive models to warn the public when risk of infection is high [6]. Hence, the present study was designed to investigate incidence of Vp and Vv in coastal waters and oysters collected in the Chesapeake Bay, MD. Since April 2019, water and oyster samples were collected from 14 stations in the Chesapeake Bay and subjected to analysis. Samples were collected weekly during the warmer months (June – Sept) and biweekly the rest of the year. Enrichment was achieved using alkaline peptone water. Vp and Vv were detected by PCR targeting toxR (Vp and Vv) [7], tlh (Vp) [8], and vvhA (Vv) [9]. Additional virulence factors were characterized for Vp by PCR (trh and tdh) [8]. Vp and Vv were enumerated by direct plating, followed by DNA colony hybridization. Vp and Vv were detected more frequently in water (Vp ca. 80%; Vv ca. 65%) than oyster samples (Vp ca. 45%; Vv ca. 30%). Pathogenic Vp (trh+) were detected more frequently during the warmer months. Studies in progress will link the number of Vp and Vv detected, ground observations of environmental parameters, and data from satellite sensing, all of which will be employed to develop a predictive model to assess risk of Vibrio spp. infection, a tool essential in an era of climate change.

References:

1. Baker-Austin C, Trinanes J, Gonzalez-Escalona N, Martinez-Urtaza J. Non-Cholera Vibrios: The Microbial Barometer of Climate Change. Trends Microbiol. 2017;25: 76–84. doi:https://doi.org/10.1016/j.tim.2016.09.008

2. Vezzulli L, Grande C, Reid PC, Hélaouët P, Edwards M, Höfle MG, et al. Climate influence on Vibrio and associated human diseases during the past half-century in the coastal North Atlantic. Proc Natl Acad Sci. 2016;113: E5062–E5071. doi:10.1073/pnas.1609157113

3. Baker-Austin C, Trinanes JA, Taylor NGH, Hartnell R, Siitonen A, Martinez-Urtaza J. Emerging Vibrio risk at high latitudes in response to ocean warming. Nat Clim Chang. 2013;3: 73–77. doi:10.1038/nclimate1628

4. CDC. Vibrio Species Causing Vibriosis. 2019. Available: https://www.cdc.gov/vibrio/faq.html

5. Jones MK, Oliver JD. Vibrio vulnificus: Disease and pathogenesis. Infect Immun. 2009;77: 1723–1733. doi:10.1128/IAI.01046-08

6. Brumfield KD, Usmani M, Chen KM, Gangwar M, Jutla AS, Huq A, et al. Environmental parameters associated with incidence and transmission of pathogenic Vibrio spp. Environ Microbiol. 2021. doi:https://doi.org/10.1111/1462-2920.15716

7. Bauer A, Rørvik LM. A novel multiplex PCR for the identification of Vibrio parahaemolyticus, Vibrio cholerae and Vibrio vulnificus. Lett Appl Microbiol. 2007;45: 371–375. doi:10.1111/j.1472-765X.2007.02195.x

8. Bej AK, Patterson DP, Brasher CW, Vickery MCL, Jones DD, Kaysner CA. Detection of total and hemolysin-producing Vibrio parahaemolyticus in shellfish using multiplex PCR amplification of tl, tdh and trh. J Microbiol Methods. 1999;36: 215–225. doi:10.1016/S0167-7012(99)00037-8

9. Panicker G, Bej AK. Real-time PCR detection of Vibrio vulnificus in oysters: comparison of oligonucleotide primers and probes targeting vvhA. Appl Environ Microbiol. 2005;71: 5702–5709. doi:10.1128/AEM.71.10.5702-5709.2005

Title: Redox-Mediated Cycling of Iron and Phosphorus by a Benthic Harmful Algal Bloom

Presenter: Cassidy Crandell

Authors: Cassidy Crandell, Corrianna Boucher, Silas Scribner, John Ferry, Timothy Shaw

Abstract: External loading of nutrients can cause conditions favorable to harmful algal bloom (HAB) formation.1 However even after external loading has stopped nutrients can still be available via internal loading from surface sediments.1 This favors benthic phytoplankton species as diagenetic processes characteristic of benthic habitats can support nutrient recycling. These processes control the redox environment at the sediment interface promoting cycling of redox-active iron phases and associated bound phosphate.2 This relationship is being investigated at Lake Wateree, a freshwater reservoir located in South Carolina. Lake Wateree has experienced persistent Lyngbya wollei blooms since 2014 despite reduced rates of external nutrient loading.3 Preliminary data in the water column through a L. wollei mat shows dissolved oxygen (DO) concentrations decrease to near zero in the mat above the sediment interface. Sediment iron and phosphorus extractions also show evidence of enrichment in both iron and phosphorus in surface sediments. As iron and phosphorus fractions cycle through the algal mats, sediment phases can also be re-suspended back into the water column through sloughing of the algal mats. 4 While iron cycling can mediate phosphorus cycling through diagenetic release within L. wollei mats (see Figure 1), the surface sediments in this environment act as a phosphorus reservoir for benthic species. These findings suggest that iron is acting as a trapping phase for sedimentary phosphorus in which L. wollei can utilize at the sediment interface and through the algal mats as redox conditions change in this environment.

References:

(1) Randall, M. C.; Carling, G. T.; Dastrup, D. B.; Miller, T.; Nelson, S. T.; Rey, K. A.; Hansen, N. C.; Bickmore, B. R.; Aanderud, Z. T. Sediment Potentially Controls In-Lake Phosphorus Cycling and Harmful Cyanobacteria in Shallow, Eutrophic Utah Lake. PLoS One 2019, 14 (2), 1–17.

(2) Pakhomova, S. V.; Hall, P. O. J.; Kononets, M. Y.; Rozanov, A. G.; Tengberg, A.; Vershinin, A. V. Fluxes of Iron and Manganese across the Sediment-Water Interface under Various Redox Conditions. Mar. Chem. 2007, 107 (3), 319–331.

(3) Lake Wateree Citizen Scientists. Personal Communication.

(4) Mendoza‐Lera, C.; Federlein, L. L.; Knie, M.; Mutz, M., The algal lift: Buoyancy‐mediated sediment transport. Water Resources Research 2016, 52, (1), 108-118.

Title: More than meets the eye – Unexpected microbial diversity in the 2018 Lake Erie HABs Grab

Presenter: Christopher S. Ward

Authors: Christopher S. Ward, Jennifer Harper, Kaitlin Plate, Justin Chaffin, Thomas Bridgeman, Edward Verhamme, Jorge Santodomingo, Timothy W. Davis

Abstract: Annual harmful algal blooms (HABs) threaten the ecological and economic well-being of western Lake Erie and the surrounding region. To reveal the patterns of an entire bloom at unprecedently high spatial resolution, researchers coordinated a single-day survey of the 2018 cyanoHAB (‘HABs Grab’, August 9th), in which all samples were collected within a 3-hour time-period across in the US portion of Lake Erie’s Western Basin. Amplicon sequencing of the V4 region of the 16S rRNA gene was performed on 100 samples to determine how the microbial community varied spatially and in relation to environmental conditions within the bloom. While wide variation in community alpha diversity was observed in and out-of-bloom, out-of-bloom communities had higher average evenness. Despite Microcystaceae being the dominant cyanobacterial family, Nostocaceae, Synechococcaceae and Pseudanabaenaceae were present in the bloom. Diatoms (mainly Aulacoseira) and cryptomonads (Teleaulax) were abundant both in and out of bloom. Common bloom-associated heterotrophic bacterial groups Flavobacteriia (Cryomorphaceae, Flavobacteriaceae), Planctomycetia (Planctomycetaceae), and Sphingobacteriia (Chitinophagaceae, Saprospiraceae) were found throughout the dataset. Environmental and biotic drivers of microbial group abundance and distribution are being explored to improve our understanding of how the interplay between algae and their microbiomes contributes to bloom formation and persistence in Lake Erie and other impacted aquatic systems.

Title: Is there a link between rising sea surface temperatures in the Gulf states of the United States of America and cases of vibriosis and the economic cost?

Presenter: Joshua Harris

Authors: Joshua Harris and Tim Taylor

Abstract:

Background

Vibrio is a gram-negative bacteria that is part of normal coastal flora. (1) Concentrations of vibrio species increase in warmer sea temperature. (2) This study looks at whether an increase in sea surface temperatures (SST) results in a rise of vibriosis cases. We assign an economic value to complications as a result of Vibrio vulnificus to give an idea of the economic impact. Vibrio vulnificus is responsible for the majority of sea-food related deaths worldwide. (3)

Methods

We analysed CDC COVIS reports, collating them into a spreadsheet showing vibrio cases by species for the Gulf states, including complication rates. We added economic data from the US Department of Agriculture who had calculated the cost of hospitalisations and mortality from cases of Vibrio vulnificus. We selected a buoy from the coast of each state from the NOAA database and an average SST was calculated for the whole year. We used Stata to perform a linear and Poisson regression on the data using cases as the dependent variable, and SST, dummy variables for states, and time as independent variables. We also used SST squared as an independent variable due to the non-linear pattern of the data.

Findings

We found a non-linear correlation between cases and SST with the above controls. As temperature rose there was at first an increase in cases, and then a decline after a certain point. Our Poisson analysis proivded P values of 0.000 for all controls, showing the change was significant. Economic analysis showed a rising cost of hospitalisation between 1999 and 2006, and an increase in mortality costs of $77,916,213.27 thus demonstrating a significant economic burden from Vibrio vulnificus.

Limitations

Prior to 2006 the CDC broke down Gulf cases by species, but this was then stopped. This was a major limitation for our study as it meant we had to analyse whole vibriosis cases rather than specifically Vibrio vulnificus for the link to SST, despite our economic data being only for Vibrio vulnificus. We are also limited by choosing only one data buoy from each state, which only gave us a snapshot of each state’s SST and ideally one would have more spatial resolution in the data.

Conclusion

The results show that increasing sea temperatures results in a rise in vibriosis cases up to a specific point. The results also show an increasing and significant economic burden as a result of this increase, with climate change this is likely to rise further. Further investigation should be undertaken to fully understand the true economic burden that rising SST and other climate variation will have on vibriosis.

Title: Metagenomic comparison of Planktothrix agardhii isolates from a Lake Erie embayment

Presenter: Katelyn M. McKindles

Authors: Katelyn M. McKindles, R. Michael McKay, Timothy Davis, and George S. Bullerjahn

Abstract: Planktothrix agardhii is a filamentous cyanobacteria species that dominates harmful algal blooms in Sandusky Bay, Lake Erie and other freshwater basins across the world. Planktothrix agardhii isolates were obtained from early (June) blooms via single filament isolation; Eight have been characterized from 2016 and 12 additional isolates have been characterized from 2018 for a total of 20 new cultures. These novel isolates were processed for metagenomic sequencing, where sequencing reads were used to generate scaffolds and contigs which were annotated with DIAMOND BLAST hit, Pfam, and GO. Analyses include whole genome alignment to generate phylogenetic trees and comparison of genetic rearrangements between isolates. Secondary metabolite production was genetically explored including microcystins, two types of aeruginosin clusters, anabaenopeptins, cyanopeptolins, microviridins, and prenylagaramides. Two common and 4 unique CRISPR-cas islands were analyzed for similar sequences across all isolates and against known Planktothrix-specific cyanophage, PaV-LD. Overall, the uniqueness of each sequence despite the same sampling location in approximately the same time of the harmful algae bloom lifecycle belies the unexplored diversity of cyanobacteria.

Title: HAB toxin cylindrospermopsin alters host microbiome signature in a translatable exposure model.

Presenter: Punnag Saha

Authors: Punnag Saha, Bryan W. Brooks, John L. Ferry, Geoff I. Scott, and Saurabh Chatterjee

Abstract: Cyanotoxins, secondary metabolites produced by the Harmful algal blooms (HAB) pose a great risk to public health systems as exposure to these cyanotoxins resulted in cases of both human and animal mortality throughout the globe. Cylindrospermopsin (CYN), a well-known cyanotoxin has gained significant attention from the scientific community in recent times because of its multi-organ toxicity, cytotoxic, genotoxic, and immunotoxic nature. CYN is highly soluble in water due to its zwitterionic form and primarily affects the liver although other organs e.g., kidney, thymus, heart, spleen can also be targeted by CYN by ectopic manifestation.

In this present study, we wanted to observe whether CYN administration in wild-type, adult, male C57B/6J mice (60μg/kg body weight) for 15 days via oral gavage can lead to an altered microbiome signature. Next-generation sequencing results showed an increased abundance of the phyla Firmicutes and Actinobacteria with parallel decreased abundance of the phyla Bacteroidetes and Verrucomicrobia in CYN-exposed mice, which primarily indicates a plausible scenario of gut dysbiosis. Also, a significantly decreased alpha diversity marked by the Shannon diversity index was observed for the CYN-exposed mice than the control group. At the species level, we observed a decreased abundance of Akkermansia muciniphilia which contributes to host immune health and gut barrier integrity in the CYN-exposed mice. Also, various gut commensals responsible for imparting various beneficial effects to the host including Bacteroides thetaiotaomicron, Blautia coccoides, Schaedlerella arabinosiphila, Duncaniella muris, Enterococcus faecium, Muribaculaceae_u_s, Oscillibacter_u_s, Parabacteroides_u_s were found to be decreased in abundance in CYN-exposed mice compared to the control group of mice, which further proves an altered bacteriome pattern. In addition, Roseburia_u_s, a known gut butyrogenic bacterium was also found to be decreased in the mice which were administered with CYN suggesting that production of butyrate, an important short chain fatty acid responsible for immune and gut health was decreased in CYN exposure.

In conclusion, our study clearly implies that CYN exposure in mice for a brief 15 days period results in microbiome dysbiosis which might further aid in CYN-associated toxicity in mice.

**This study was supported by NIH/NIEHS Grant 1P01ES028942-01 awarded to Dr. S. Chatterjee.

Title: Sulfolipid profiles of Microcystis aeruginosa and cyanobacterial blooms as an indicator of P availability

Presenter: Robbie M. Martin

Authors: Robbie M. Martin, Maddie K. Denney, Helena L. Pound, Justin D. Chaffin, George S. Bullerjahn, Robert M. McKay, Katarina A. Jones, Hector F. Castro, Shawn R. Campagna, Steven W. Wilhelm

Abstract: Phosphorus (P) scarcity limits productivity in limnetic systems while its oversupply drives eutrophication that frequently leads to formation of cyanobacteria-dominated harmful algal blooms. Even in eutrophic lakes, P can be seasonally limiting and influences bloom dynamics. Marine phytoplankton alter their lipid profile by increasing the proportion of sulfolipids in response to P scarcity. We asked whether the freshwater bloom-forming cyanobacterium Microcystis spp. responds similarly to P availability. We tested this using laboratory cultures, Lake Erie mesocosms, and in situ measurements of Microcystis spp. blooms in Lake Erie. The ratio of sulfoquinovosyl diaclyglycerol (SQDG) to phosphatidylglycerol (PG) was used to monitor lipid profile remodeling. In batch cultures of M. aeruginosa NIES-843, the SQDG:PG ratio increased from ~0.9 to ~3.3 with decreasing initial P concentration. In mesocosms, SQDG:PG increased in P-limited controls from ~6 to ~11 after 48 hr. In P-addition treatments, the ratio decreased from ~6 to ~3 after 48 hr. In non-P-limited mesocosms, the ratio was unchanged in controls after 48 hr and P-addition treatments had no effect. In Lake Erie in situ measurements, SQDG:PG showed a modest but significant inverse correlation (Pearson’s r = -0.42) with total dissolved P. There was no correlation with either soluble reactive P or N:P ratio. This study demonstrates that Microcystis remodels its lipid profile in response to P scarcity and that sulfolipid content might serve as indicator of P availability. Extending this idea, we propose that this metric provides an opportunity to monitor the integrated, short-term nutrient history of a cyanobacterial population.

Title: Omics analyses reveal the presence and expression of diverse and novel gene clusters for biosynthesis of secondary metabolites in Microcystis blooms

Presenter: Colleen E. Yancey

Authors: Colleen E. Yancey, Fengan Yu, David, H. Sherman, Gregory J. Dick

Abstract: Cyanobacterial Harmful Algal Blooms (cHABs) occur globally and have several negative outcomes on the functioning and productivity of freshwater systems. These blooms are dominated by the cyanobacteria Microcystis aeruginosa, which is capable of producing the hepatotoxin microcystin (MC), the most notorious and best studied secondary metabolite produced by Microcystis. However, little is known about the presence and synthesis of other potentially novel and harmful secondary metabolites produced by Microcystis in natural communities. To that end, we leveraged metagenomic and metatranscriptomic data from the 2014 western Lake Erie cHAB to identify Microcystis genes encoding secondary metabolites and tracked their patterns of expression in natural populations of this toxin-producing microorganism. Through de novo assembly, biosynthetic gene cluster (BGC) mining, and differential expression analysis we demonstrate the potential for diverse secondary metabolites, both known and novel, to be produced in Microcystis blooms. Several of these compounds may also exhibit toxic properties and are of high interest for future studies and monitoring efforts. Finally, this work identifies abiotic and biotic factors that may influence BGC expression, including N and P availability and the abundance of potential competitors, suggesting multi-faceted controls on the production of Microcystis secondary metabolites in situ.

Title: The effects of day-to-day changes in weather and water conditions on the environmental fate of Lyngbya wollei toxins

Presenter: John Ferry

Authors: T. L. Metz, S. P. Putnam, G. I. Scott, and J. L. Ferry

Abstract: Lyngbya wollei (or Microseira wollei), is a potentially toxic freshwater benthic cyanobacteria known to produce several structural analogues of saxitoxin. The current multi-year study is based on samples obtained from a group of Lyngbya wollei blooms that are spreading upstream through a series of hydroelectric and drinking water reservoirs on the Catawba River in South Carolina. They were first documented in Lake Wateree SC in 2013 and have now moved northward at least as far as Lake Wylie SC. Citizen scientist volunteers began mapping bloom biomass in 2016; based on their measurements the current estimate is approximately 5x106 kg Lyngbya wollei in Lake Wateree alone. The engaged lakes serve as the primary drinking water resource to approximately 100,000 people. If the growth continues northward it will soon colonize Lake Norman, the primary water supply to Charlotte NC.

Lyngbya wollei blooms typically generate significant biomass, in the vicinity of 10kg/m2, and this material is often found washed up along the shorelines of affected lakes. The current work reports the ready release of four different saxitoxin analogues (the Lyngbya wollei toxins, or LWT 1, 4,5, and 6) from exposed Lyngbya wollei biomass as it weathered. The released toxins were unstable in lakewater at conditions relevant to those occurring in the blooms. The environmental half-life of each of the measured LWTs was determined in filter sterilized lake water as a function of temperature (10oC-40oC) and pH (6-10). The primary degradation mechanism was determined to be base catalyzed hydrolysis. Two hydrolysis products (LWT4 and decarbamoyl saxitoxin) were quantified and their yields were determined to be essentially quantitative. The response surfaces describing toxin half-life vs pH and T were modeled as quadratics with allowed interaction effects between the two variables. Given the high toxicity of the decarbamoyl saxitoxin degradation product it was determined that conditions corresponding globally to the briefest half-lives for the LWTs also corresponded to the highest net toxicity of the water column. The measured LWTs from Lake Wateree were converted to the effective mass of saxitoxin in the lake, based on the previously reported toxicity of LWT5 (the most toxic LWT) and decarbamoyl saxitoxin in the saxitoxin mouse assay. Based on the pre-degradation quantity of LWT 5 measured in the bloom biomass the lake was estimated to hold the equivalent of 8kg of saxitoxin; if complete degradation was assumed the saxitoxin equivalent mass increased to 25-30 kg.

Title:

Presenter: Beth Bair

Authors:

Abstract: Single cell inductively coupled plasma mass spectrometry (SC-ICP-MS) provides a novel means to quantitatively measure nanoparticles and nanoplastics associated with intact, individual biological cells by ICP-MS. Analysis of intact (unlysed) cells is fundamental to correctly interpret data from SC-ICP-MS. Two types of algal cells, Cryptomonas ovata and Cryptomonas ozolini, were used to test cell lysis during sample preparation and introduction into an ICP-MS. The results show the combined optimization of cell preparation and instrumentation parameters yields successful transport of intact cells into the plasma where they are then ionized. Only 8% of Cryptomonas ovata cells and 19% of Cryptomonas ozolini cells made it through the sample injector, representing the fraction of cells that enter the plasma of an ICP-MS. However, of that fraction, approximately 85% of Cryptomonas ovata and Cryptomonas ozolini cells were effectively transported in the plasma unlysed, under optimal conditions. Optimal gas and sample flow conditions for testing cell lysis were: nebulizer gas flow of 0.4 mL min-1, additional gas flow of 0.7 mL min-1 and sample flow rate between 0.16 – 0.33 mL min-1. This method provides a basis for understanding how to prepare cell samples and establish instrumentation parameters for the accurate analysis of cell-associated nanoparticles using SC-ICP-MS.

Title: Developing a comparative understanding of the aquatic toxicology of (±) anatoxin-a and (+) anatoxin-a in two common fish models

Presenter: Lea M. Lovin

Authors: Lea M. Lovin, Laura Langan, Sujin Kim, Raegyn B. Taylor, Kendall R. Scarlett, C. Kevin Chambliss, Saurabh Chatterjee, J. Thad Scott, Bryan W. Brooks

Abstract: Harmful algal bloom toxins present risks to public health and the environment. Anatoxin-a is a globally found neurotoxic cyanobacterial toxin that affects growth, reproduction, and survival of aquatic organisms. Few studies have examined influences of anatoxin-a on gene expression and behavior with common fish models. Therefore, after performing probabilistic hazard assessments, here we studied larval fathead minnow and zebrafish responses following exposure to (±) anatoxin-a at environmentally relevant, analytically verified concentrations We found duration and distance of fathead minnows swimming at the highest speed (>20 mm/s) was significantly lowered (ANOVA, α = 0.1) by (±) anatoxin-a in 0.1, 1, and 1.5 mg/L treatments, while the opposite occurred with zebrafish, which showed increased distance, duration, and changes in movement at the highest speed, though not significant. We examined gene expression focusing on genes related to neurotoxicity, oxidative stress, and DNA damage. While there was little change in zebrafish, fathead minnows showed upregulation in many neurotoxicity related genes, though only elavl3 was significant (ANOVA, α = 0.05) as well as downregulation of gst and cyp3a126. This suggests fathead minnows may be more sensitive to this toxin based on these endpoints. We subsequently have repeated these studies with (+) anatoxin-a, previously reported as the only enantiomer produced by cyanobacteria and observed differential sensitivities among endpoints and between organisms with high mortality in fathead minnows >0.5 mg/L concentrations and showing a largely refractory response in zebrafish. Comparative understanding of cyanotoxins is necessary to support robust assessments and management of algal blooms.

Title: Abiotic factors affecting chytrid (Chytridiomycota) infection rates on its host Planktothrix agardhii

Presenter: Ryan Wagner

Authors: Ryan Wagner, Katelyn McKindles and George Bullerjahn

Abstract: Sandusky Bay, Lake Erie (USA) is home to recreational fishing, tourism, boating, and swimming, and is a drinking water source to about 50,000 residents. It is also plagued by annual cyanobacterial blooms. Planktothrix agardhii, which dominates Sandusky Bay, can produce microcystin toxins that are known to be harmful to humans and animals. It is important that we understand the mechanisms driving and influencing these blooms. In this study, we examine Chytridiomycota (chytrids) and how these aquatic fungi can infect P. agardhii blooms. Rhizophydium sp. are known obligate parasites to Planktothrix and these species have been found and isolated from the waters of Sandusky Bay (McKindles et al. 2021). We investigated the spatial distribution of infections along with the effect turbulence has on infectivity. In lake mesocosms, coupled with lab experiments, suggest that small amounts of water turbulence can significantly reduce the infectivity of chytrids. Additionally, there was no statistical difference in spatial distribution found in the lab experiments. This is likely due to the low water volume and position of light. Understanding different environmental conditions and the effect they have on infectivity provides valuable insights into controlling factors that may be limiting chytrid pathogenesis.

References:

McKindles, K.M., A.N. Jorge, R.M. McKay, T.W. Davis and G.S. Bullerjahn. 2021. Isolation and characterization of Rhizophydiales sp. (Chytridiomycota), an obligate parasite of Planktothrix agardhii in a Laurentian Great Lakes embayment. Appl. Environ. Microbiol. 87(4): e02308-20.

Title: The effects of salinity and N:P on N-rich toxins by both an N-fixing and non-N-fixing cyanobacteria

Presenter: Nicole D. Wagner

Authors: Felicia S. Osburn, Nicole D. Wagner, Raegyn B. Taylor, C. Kevin Chambliss, Bryan W. Brooks, J. Thad Scott

Abstract: Freshwater ecosystems are experiencing increased salinization. Adaptive management of harmful algal blooms (HABs) contribute to eutrophication/salinization interactions through the hydrologic transport of blooms to coastal environments. We examined how nutrients and salinity interact to affect growth, elemental composition, and cyanotoxin production/release in two common HAB genera. Microcystis aeruginosa (non-nitrogen (N)-fixer and microcystin-LR producer; MC-LR) and Aphanizomenon flos-aquae (N-fixer and cylindrospermopsin producer; CYN) were grown in N:phosphorus (N:P) 4 and 50 (by atom) for 21 and 33 days, respectively, then dosed with a salinity gradient (0 – 10.5 g L-1). Both total MC-LR and CYN were correlated with particulate N. We found Microcystis MC-LR production and release was affected by salinity only in the N:P 50 treatment. However, Aphanizomenon CYN production and release was affected by salinity regardless of N availability. Our results highlight how cyanotoxin production and release across the freshwater – marine continuum is controlled by eco-physiological differences between N-acquisition traits.

Title: Investigating effects of developmental domoic acid exposure on neuroimmune cells in larval zebrafish (Danio rerio)

Presenter: Alia Hidayat

Authors: Alia Hidayat, Neel Aluru

Abstract: Domoic acid (DA) is a neurotoxin produced by the marine diatom Pseudo-nitzschia that can accumulate in shellfish. When contaminated shellfish are consumed, DA can cause an illness called amnesic shellfish poisoning (ASP) associated with nausea, vomiting, memory loss, seizures, and in extreme cases, death. While federal seafood regulations prevent acute poisoning events, recent studies have suggested that there may be effects of low-level exposure to DA at concentrations below regulatory limits, including memory deficits1,2. Previous studies in rodents3–6, non-human primates7 and zebrafish8,9 suggest that early developmental stages are particularly susceptible to DA toxicity and have identified effects on central nervous system (CNS) function. Little is known regarding the cellular mechanisms that underlie early life sensitivity. This work tests the hypothesis that developmental DA exposure causes activation of microglia10,11. Microglia, the macrophages of the CNS, facilitate the brain's immune response and are implicated in harmful inflammation and neurotoxicity following toxicant exposure12–14. In order to understand the effects of DA exposure on this cell type, we utilized the transgenic zebrafish line tg(mpeg1:mCherry), which labels microglia and macrophages. Larvae were exposed to varying concentrations of DA (0, 0.06, 0.1, 0.3ng) via hindbrain ventricle injection at two developmental stages (2 and 4 days post fertilization or dpf) to identify windows of susceptibility. Using confocal imaging, we assessed microglial abundance and morphology. Interestingly, there were significant differences in sensitivity between the tested developmental time points. At 4 dpf, exposure to 0.3ng DA causes changes in microglial morphology associated with activation. These changes were accompanied by alterations in gross morphology, including cardiac and yolk sac edema, brain necrosis, lack of swim bladder, and spinal curvature. At lower concentrations (0.1 and 0.06ng), neither gross morphological changes nor microglial effects were observed, suggesting that microglial effects might be specific to higher doses of DA that produce acute neuronal death. We are pursuing further studies to determine the effects of developmental DA exposure on inflammatory markers and cell death. Additionally, we will assess neurodegeneration and behavior in adult zebrafish to determine whether developmental exposure affects later life health outcomes. This work is supported by an NSF Graduate Research Fellowship (Award #112374) and the Woods Hole Center for Oceans and Human Health (NIH P01ES028938 Diversity Supplement and NSF OCE 1840381).

REFERENCES:

1. Grattan, L. M. et al. The association between razor clam consumption and memory in the CoASTAL cohort. Harmful Algae 57, 20–25 (2016).

2. Grattan, L. M. et al. Repeated dietary exposure to low levels of domoic acid and problems with everyday memory: Research to public health outreach. Toxins (Basel). 10, (2018).

3. Gill, D. A., Perry, M. A., McGuire, E. P., Pérez-Gómez, A. & Tasker, R. A. Low-dose neonatal domoic acid causes persistent changes in behavioural and molecular indicators of stress response in rats. Behav. Brain Res. 230, 409–417 (2012).

4. Dakshinamurti, K., Sharma, S. K., Sundaram, M. & Watanabe, T. Hippocampal changes in developing postnatal mice following intrauterine exposure to domoic acid. J. Neurosci. 13, 4486–95 (1993).

5. Gill, D. A. et al. Neonatal exposure to low-dose domoic acid lowers seizure threshold in adult rats. Neuroscience 169, 1789–1799 (2010).

6. Adams, A. L., Doucette, T. A., James, R. & Ryan, C. L. Persistent changes in learning and memory in rats following neonatal treatment with domoic acid. Physiol. Behav. 96, 505–512 (2009).

7. Grant, K. S. et al. Preclinical modeling of exposure to a global marine bio-contaminant: Effects of in utero Domoic acid exposure on neonatal behavior and infant memory. Neurotoxicol. Teratol. 73, 1–8 (2019).

8. Panlilio, J. M., Aluru, N. & Hahn, M. E. Developmental Neurotoxicity of the Harmful Algal Bloom Toxin Domoic Acid: Cellular and Molecular Mechanisms Underlying Altered Behavior in the Zebrafish Model. Environ. Health Perspect. 128, 1–19 (2020).

9. Panlilio, J. M., Jones, I. T., Salanga, M. C., Aluru, N. & Hahn, M. E. Developmental Exposure to Domoic Acid Disrupts Startle Response Behavior and Circuitry in Zebrafish. Toxicol. Sci. 182, 310–326 (2021).

10. Mayer, A. M. et al. Effect of a short-term in vitro exposure to the marine toxin domoic acid on valiability, tumor necrosis factor-alpha, matrix metalloproteinase-9 and superoxide anion release by rat neonatal microglia. BMC Pharmacol. 1, (2001).

11. Lefebvre, K. A. et al. A novel antibody-based biomarker for chronic algal toxin exposure and sub-acute neurotoxicity. PLoS One 7, e36213 (2012).

12. Levesque, S. et al. Diesel Exhaust Activates and Primes Microglia: Air Pollution, Neuroinflammation, and Regulation of Dopaminergic Neurotoxicity. Environ. Health Perspect. 119, 1149–1155 (2011).

13. Purisai, M. G. et al. Microglial activation as a priming event leading to paraquat-induced dopaminergic cell degeneration. Neurobiol. Dis. 25, 392–400 (2007).

14. Wu, X. F. et al. The role of microglia in paraquat-induced dopaminergic neurotoxicity. Antioxidants Redox Signal. 7, 654–661 (2005).

Title: Base Excision Repair is an Important Component of Neuronal Cell Survival Following Exposure to Ciguatoxins

Presenter: Jennifer Clark

Authors: Jennifer Clark, Alison Robertson, and Robert W Sobol

Abstract: Ciguatera poisoning (CP) is caused by consuming fish containing naturally occurring ciguatoxins (CTXs) derived from the benthic dinoflagellate Gambierdiscus. Herbivores inadvertently consume the toxigenic dinoflagellates through metabolic biotransformation processes, an bioconvert the algal metabolites to CTX through the food web. CTX are known to activate voltage gated sodium ion channels, resulting in prolonged repolarization that is characterized by increased intracellular calcium. The elevated intracellular calcium results in increased Reactive Oxygen Species (ROS) that can damage cellular macromolecules such as DNA, RNA and proteins. Using the cell arrayed Single Cell Gel Electrophoresis (CometChip Assay), we have shown that exposure of neuronal cells to CTX induces genomic DNA damage. Furthermore, this damage was prevented using the sodium channel blocking tetrodotoxin (TTX). The Base Excision Repair (BER) pathway repairs DNA base modifications such as those resulting from ROS. Using CRISPR/- Cas9 to mutate (knock-out) key BER proteins including DNA Polymerase Beta and XRCC1, we were able to sensitize the human neuronal cell line SHSY5Y to CTX exposure. These data demonstrate that CTX damages cellular genomic DNA and this damage is repaired by enzymes of the BER pathway. These studies suggest that susceptibility to CTX may correlate with neuronal BER capacity.

Title: A tiered ovarian toxicity screening identifies ovarian toxic effects of perfluorononanoic acid (PFNA) on gonadotropin-dependent folliculogenesis and ovulation

Presenter: Pawat Pattarawat

Authors: Pawat Pattarawat, Yingzheng Wang, Jiyang Zhang, Eunchong Kim, Qiang Zhang, Ji-Yong, Julie Kim, and Shuo Xiao

Abstract: Per-and Polyfluoroalkyl substances (PFASs) are an emerging group of man-made endocrine disrupting chemicals (EDCs). PFASs have been widely used in industry and consumer products since 1940s. Due to the highly stable C-F bonds, PFASs are non-biodegradable and persist in the environment, including ocean and lake waters, making human exposure to PFASs inevitable. In the present study, we aimed to use a 3-tiered ovarian toxicity screening approach starting from our established 3D encapsulated in vitro follicle growth (eIVFG) system to investigate the ovarian toxic effects of 6 PFAS compounds, including PFOA, PFOS, PFNA, PFHpA, PFBS, and GenX. In Tier 1, immature mouse ovarian follicles were treated with human relevant exposure concentrations of each PFAS at 0, 0.001, 0.01, 0.1, 1, 10, 100, and 250 μM during the entire period of eIVFG, covering the events of gonadotropin-dependent follicle maturation, hormone secretion, ovulation, and luteinization. Results showed that the long-chain PFASs (PFOA, PFOS, and PFNA) but not the short-chain PFASs (PFHpA, PFBS, and GenX) inhibited follicle development, ovulation, and progesterone secretion at 100 and/or 250 μM. In addition, PFNA and PFHpA at or higher than 0.01 μM decreased estradiol secretion. PFNA was next advanced to the Tiers 2 and 3 screening, including the specific window exposure and ovarian toxicity assessment in the Tier 2 and molecular target identification in the Tier 3. When follicles were treated with 250 μM PFNA during the gonadotropin-dependent follicle maturation window, PFNA significantly inhibited follicle development and compromised ovulation and progesterone secretion, suggesting that exposure to PFNA disrupts follicle maturation to result in the secondary defective ovulation and luteinization. However, RT-qPCR results showed that 250 μM PFNA did not change the expression of follicle maturation signature genes, such as Cyp19a1, Fshr, and Lhcgr, indicating other involved mechanisms for the defective follicle maturation and estradiol secretion. When follicles were treated with 250 μM PFNA during the ovulation window only, there were significantly decreased ovulation rate and progesterone secretion, suggesting that PFNA also directly affects follicle ovulation and luteinization. RT-qPCR results revealed that exposure to 250 μM PFNA during ovulation suppressed the expression of follicle rupture-related genes, Plau and Plat, as well as the luteinization-related genes, Star and Cyp11a1. The following in situ zymography experiment confirmed that 250 μM PFNA inhibited the activation of gelatinases, which are essential for the extracellular matrix (ECM) remodeling and follicle rupture during ovulation. Taken together, these results suggest that the long-chain PFASs are more ovarian toxic compared to the short-chain PFASs; moreover, environmentally-relevant exposure to PFNA interferes with gonadotropin-dependent folliculogenesis and ovulation through different molecular mechanisms.

Title: Microbiome development on seawater-incubated plastic preproduction pellets reveals distinct and predictive community compositions

Presenter: Christopher S. Ward

Authors: Christopher S. Ward, Zoie Diana, Beatriz Orihuela, Thomas P. Schultz, Dan Rittschof

Abstract: Plastics of various chemistries pollute global water bodies, where toxic chemicals leach out with potentially detrimental impacts on the surrounding ecosystems. We found that barnacle larvae exhibited acute toxicity towards seawater leachates from seven recycle-categories of plastic pre-production pellets, from as low as 0.01 mg of pellet per ml of seawater soaked for 24 hours. Having previously observed that macro-organismal settlement on fouling management coatings of various toxicities can be used to predict the toxicity of the coatings, we hypothesized that the assembly of microbial biofilms on plastic would be similar. We exposed plastic pellets to the same flowing ambient seawater (Pivers Island NC) for 70 days and sampled at 8, 16, 24, 32 and 70 days. The microbiomes that developed on the pellets were characterized using amplicon sequencing of V3-V4 regions of bacterial 16S ribosomal RNA genes. Many observed bacterial families are generalist marine copiotrophs or associated with oil spills and hydrocarbon degradation. Microbiomes colonizing plastic pellets followed successional trajectories over the incubation duration, yet varied between each plastic type. A machine learning sample classifier correctly identified plastic types from microbiome composition with 93% accuracy, demonstrating the potential application of microbial forensics to discern chemical composition of marine plastic pollution that would otherwise be difficult to identify through chemical analysis.

Title: Phthalate exposure in bottlenose dolphins (Tursiops truncatus) and the potential for endocrine disruption

Presenter: Miranda Dziobak

Authors: Miranda Dziobak, Randall S. Wells, Emily Pisarski, Ed Wirth, Leslie Hart

Abstract: Phthalates are a class of chemicals commonly added to consumer goods, including cleaning products, personal care products, and plastics. Extensive production and use have resulted in widespread environmental phthalate contamination and subsequent wildlife exposure. This is concerning as epidemiological evidence from human and laboratory studies has linked phthalate exposure with endocrine disruption, thus potentially leading to adverse impacts on reproduction and development. Mammals quickly metabolize phthalate parent compounds, so urinary metabolite concentrations have been widely used to indicate exposure. We recently detected phthalate metabolites in approximately 75% of sampled common bottlenose dolphins (Tursiops truncatus; n=51) from Sarasota Bay, Florida, at concentrations significantly higher (p<0.05) than human reference populations from the Centers for Disease Control and Prevention’s National Health and Nutrition Examination Survey (NHANES). The health impacts from this exposure, however, are largely unknown. This study applied findings from human studies to target investigations of endocrine disruption in exposed animals. More specifically, given previous findings linking phthalate exposure with reproductive organ abnormalities, pregnancy loss, and developmental issues in human epidemiological studies, we conducted correlation tests to examine associations between bottlenose dolphin concentrations of mono-2(ethyhexyl) phthalate (MEHP) and adrenal, reproductive, and thyroid hormone levels measured in serum. Twenty-eight dolphins had detectable concentrations of MEHP (GM=4.57ng/mL; 95% CI=2.37-8.80). Though laboratory studies have previously found relationships between testosterone and MEHP detection, our study did not find a significant relationship. In fact, no associations were found between any reproductive or adrenal hormone with detectable MEHP concentrations. Our study did find that adult female and male free thyroxine (FT4) were significantly correlated with urinary MEHP concentrations (adult female Kendall’s tau= 0.36, p= 0.04; adult male Kendall’s tau= 0.42, p= 0.02). While specific health impacts are currently unknown, our study demonstrated phthalate exposure may be disrupting thyroid hormone homeostasis. Evidence from human studies has shown an association between phthalate exposure and serious health effects. Since dolphin urine sampled for our study had higher detectable MEHP concentrations than human reference populations, further research is warranted to understand how phthalate exposure may be influencing dolphin health.

Title: Predictive Risk Assessment of Biothreats along US Coast: A case study from Florida

Presenter: Lauren Diaz

Authors:

Abstract: With sea levels on the rise, there is an increasing concern of the resiliency of coastal communities to withstand encroaching flooding driven by extreme weather events. It is estimated that the majority of the human population lives within 50 miles of a coast while several pathogens, or biothreats, are frequently reported in coastal regions (Crowell et al., 2007). We hypothesize that a dynamic equilibrium exists between biothreats and human populations such that humans are not exposed to infection unless a substantial change occurs in the underlying social structure driven by extreme hydroclimatic events. Therefore, we aim to develop a predictive understanding of how and when hydroclimatic processes and coastal ecology of biothreats interact with human populations such that appropriate mitigation and intervention strategies can be devised. Because Florida coasts are prime regions to study these dynamics, they served as the focus of this research. Key hydroclimatic variables were identified and derived from satellite-based, remotely sensed datasets. Their trends were associated with the abundance of biothreats, when available. Trends observed thus far show that the abundance of biothreats are aligned with anomalous precipitation, temperature, and ocean color products. Biothreat occurrence was collected from various sources, which include literature, Centers for Disease Control, and Florida Department of Health. The results of this research will be realized in a statistical measurement tool called the Biothreats Assessment Tool (BAT).

References

Crowell, M., Edelman, S., Coulton, K., & McAfee, S. (2007). How Many People Live in CoastalAreas?1. Journal of Coastal Research, 23(5). https://doi.org/10.2112/07A-0017.1

Title: Early-Life microcystin exposure alters host resistome signature and enhances Vibriosis severity

Presenter: Saurabh Chatterjee

Authors:

Abstract: Climate change stressor microcystin is increasingly detected in regions around the world largely because of wide scale algal blooms. It is extensively reported that microcystins are potent cytotoxins that alter gut microbiome and result in ectopic toxicity in the host. Toxins, especially that are metabolites of certain prokaryotes have antibiotic function and often trigger development of antibiotic resistance in bacteria. We hypothesized that microcystin has an intrinsic antibiotic characteristic that may confer the development of antibiotic resistance in host gut bacteria. Further, the altered resistome profile that comprises of the antimicrobial resistance genes and the mobile genetic elements that harbor them may lead to increase in disease severity if challenged by a known pathogen such as Vibrio Vulnificus, an emergent pathogen of concern in coastal waters. Results showed that an early life sub-chronic microcystin exposure in C57BL6 mice altered gut microbiome and resistome with increased counts of several classes of antibiotic resistance genes including those against beta-lactam classes within the host when compared to mice that were not exposed to the toxin. Further, mice that were challenged with an oral exposure of Vibrio Vulnificus, showed significantly decreased innate immune surveillance (decreased TLR2 and TLR4 expression in the gut), increased serum levels of C-reactive protein, a critical biomarker for inflammation and septicemia, increased levels of IL6, a marker of sepsis, and had severe outcomes in liver pathology similar to acute liver failure. These novel results have huge public health implications since antibiotic resistance is a huge concern in critical care medicine and treatment of hospital acquired infections. Further, increased cases of Vibrio Vulnificus infections are being reported worldwide with higher mortality rates. Our results may provide clues to a mechanistic pathway of increased pathogenicity of Vibrios with parallel prevention efforts via correction of resistome using fecal microbiota transplant.

This study is part of the larger project related to my lab’s efforts to model multiple exposures from climate change stressors and is led by PhD student Punnag Saha **This study was supported by NIH/NIEHS Grant 1P01ES028942-01, Project#4 awarded to Dr. S. Chatterjee.

Title: Evaluating Airborne Harmful Cyanobacterial Bloom Compounds as a Public Health Concern in the Chowan River, NC

Presenter: Haley E. Plaas

Authors: Haley E. Plaas, Karsten Baumann, Ryan W. Paerl, Kimberly J. Popendorf, Colleen Karl, Jill Paxson, Naomi Y. Chang, Joel Sanchez, Hwa Hwang, Malcolm A. Barnard, Daniela Maizel, and Hans W. Paerl

Abstract: In addition to obvious negative effects on water quality, recent findings suggest that harmful cyanobacterial blooms (CHABs) impact air quality via primary spray aerosol emissions carrying cyanobacterial cells and cyanotoxins. The inhalation of microcystin (MC), a potent liver cyanotoxin, elicits a more cytotoxic response compared to other exposure routes. People are most likely to come into contact with aerosolized CHAB toxins during aquatic recreational and fishing activities, but these aerosols can persist in communities onshore. Thus, the objective of our study was to quantify CHAB toxins and examine CHAB DNA sequence diversity in the airshed of the Chowan River, North Carolina, a eutrophic estuary facing recurrent CHABs. Our field campaign (Summers 2020 and 2021) was the first to evaluate inhalation as a potential exposure pathway to MC in NC. From June to Oct., several two-week integrated, daytime PM2.5 (particulate matter with diameters <2.5 μm) samples were collected using medium-volume samplers (Tisch Environmental Inc.). Offline analytical methods were applied to examine DNA and MC in water and aerosol samples. Physicochemical water parameters, ambient PM2.5 mass concentration, and meteorological conditions were also recorded in parallel. In 2020, CHAB genera dominated the algal community biomass (~45%), but maximum toxin concentrations and toxin encoding genes (mcyA) in water samples were low (<<1 μg/L), ultimately yielding aerosol concentrations below the limits of quantification. However, two cyanotoxin congeners which have previously been demonstrated to be enriched in aerosol, MC-LA (microcystin leucine-alanine) and MC-LR (leucine-arginine), were quantified in water samples. Airborne CHAB populations are still being evaluated based on amplicon sequencing. In Summer 2021, we refined our aerosol collection approaches to better characterize the physicochemical properties of airborne CHAB toxins. Due to the fact that cyanotoxins primarily exist as endotoxins (intracellular), we hypothesized that toxins would be aerosolized within intact cells and concentrated in the coarse mode (PM10). Using high-volume samplers (Tisch Environmental Inc.), we simultaneously collected PM2.5 and PM10, and performed the same offline toxin analyses.

Title: Disinfection By-Product Formation from Harmful Algae and Algae-Impacted Source Waters

Presenter: Md. Tareq Aziz

Authors: Md. Tareq Aziz, Danielle C. Westerman, Caroline O. Granger, Samuel P. Putnam, John L. Ferry, and Susan D. Richardson

Abstract: Worldwide, harmful algal blooms (HABs) are a major concern due to climate change and are especially problematic in the United States since algae can impact drinking water treatment plants that depend on surface waters. For example, in August 2014, the water supply of 400,000 people in Toledo, Ohio, was shut down due to toxic HABs in the source water. The objectives of this work include analytical measurements of toxins from harmful algal blooms and investigating the potential formation of halogenation by-products from them. HAB organic matter can also contribute to the formation of disinfection by-products (DBPs), which are linked to various adverse health effects. In this work, 64 priority DBPs were quantified from the disinfection of live harmful algae: Lyngbya wollei and Phormidium. Controlled lab experiments were conducted at pH 7. Lyngbya wollei algae was collected from Lake Wateree, Lake Marion, and a from a small town in South Carolina whose drinking water reservoir was experiencing a Lyngbya bloom; Phormidium algae was collected from Lake Wateree, South Carolina. These algae were chlorinated and/or chloraminated in nano-pure water or source water to mimic drinking water treatment conditions to better understand DBP formation in algae impacted drinking water. The impact of Br- and Iions was also investigated. Disinfection by-products were also measured from finished drinking water of the algae-impacted drinking water treatment plant and from controlled laboratory reactions of live algae and source waters. DBPs, both regulated and unregulated, were quantified by gas chromatography coupled with mass spectrometry (GC-MS).

Title: Coastal Stormwater Pond Pollutants and the Potential for Development of Antibiotic Resistance in Vibrio and Enterococcus Bacteria

Presenter: Cassie Horton

Authors:

Abstract: The Southeastern coastal plain is the most rapidly urbanizing region in the United States. Landscape ecology changes which increase imperviousness lead to alterations in the hydrological cycle, increasing runoff of nonpoint source (NPS) pollution. NPS runoff is discharged into stormwater retention ponds to reduce loading into coastal ecosystems. In the South Carolina coastal zone there are >21,594 retention ponds, which concentrate NPS pollution such as chemical contaminants, nutrients, and microbes, at levels much higher than in adjoining estuarine waters.

Studies of legacy pollutants and contaminants of emerging concern in retention ponds indicate elevated levels of trace metals which exceed sediment quality guidelines (SQGL), in addition to the presence of emerging contaminants like clinically relevant antimicrobials. Such ponds have also been shown to contain high levels of fecal coliform bacteria. Other investigations have shown significant association between trace metals contamination in surface waters and sediments with increased rates of antibiotic resistance (ABR). Given the nature of retention ponds to isolate and concentrate pollutants like trace metals along with bacterial contaminants, these ponds may pose a public health risk from drug-resistant microbes. Even in the absence of human pathogens, affected microbes may pass on resistance genes to harmful bacteria in nearby estuaries, where they may be transferred during flood events. With the increase in extreme rainfall events that accompanies climate change, such conditions will increase in frequency and severity.

Interactions of trace metals commonly found in SC ponds and estuaries (As, Cu, Zn), antimicrobial products (triclosan, ciprofloxacin, and oxytetracycline), and aquatic pathogenic bacteria (Vibrio vulnificus and Enterococcus faecium) will be discussed in terms of how they may enhance antibiotic resistance and underlying mechanisms for upregulation of resistance genes. Additionally, exposure data for V. vulnificus and E. faecium grown in the presence of antimicrobials and/or trace metals will be presented alongside resistance profiles of the organisms following single or binary exposure.

Title: Rapid, portable and multiplexed detection of freshwater harmful algal bloom-forming genera

Presenter: Katelyn Brown

Authors:

Abstract: Freshwater cyanobacteria harmful algal blooms (CHABs) are being observed more frequently around the world due to eutrophication, more robust monitoring programs and a changing climate. Oftentimes, CHABs result in the production of toxins such as microcystins, cylindrospermopsins, anatoxins, and saxitoxins, that can be harmful or fatal to humans and other animals therefore quick but informed management decisions are needed. To reduce the time between a suspected bloom and subsequent management decisions, a rapid, easy-to-use, in-field, multiplexed sandwich hybridization assay (SHA) will be developed to quickly recognize 7 prominent bloom-forming and potentially toxin -producing cyanobacterial genera. The initial genera being targeted for SHA include Microcystis, Anabaena/Dolichospermum, Aphanizomenon, Planktothrix, Cylindrospermopsis, Lyngbya/Microseira, and Phormidium/Microcoleus. To achieve this multiplexed assay, oligonucleotide probes are designed to target the 16S rRNA. If the target genera are present in a sample, an estimate of cell density will be determined from probe-conferred fluorescence. These probes will also utilize zip codes, an additional oligonucleotide sequence that will allow multiplexing and will enhance assay sensitivity. Initial testing of probe specificity has utilized fluorescent in-situ hybridization and probes with the best results will soon be adapted into SHA. Additionally, phylogenetic analysis of a large dataset of cyanobacterial sequences is in progress. This will help to identify areas in the 16S rRNA where the most specific probe sequences can be found for each target. In comparison to traditional methods, the SHA will be able to identify potentially toxin-producing genera more quickly and at a lower cost to lake managers.

Title: Evaluating the baseline and short-term human health risks associated with exposure to toxic cyanobacteria species.

Presenter: Addison C. Testoff

Authors: Addison C. Testoff, Daniela Maizel, Courtney Broedlow, Marina Mai, Larry Brand, Helena Solo-Gabriele, Nichole R Klatt, Natasha Schaefer Solle, Kimberly J. Popendorf and Alberto J. Caban-Martinez

Abstract:

Background: Annually, between spring to early the fall, blooms of blue-green algae containing cyanotoxins, specifically microcystin (MC), are common in south Florida freshwater ecosystems. Despite the known hepatotoxic characteristics of microcystin, limited information exists characterizing the adverse human health effects due to recurrent low dose exposure.

Objective: Characterize the baseline blue-green algae exposure reported by participants of the Diversity and Innovation in Screening and Prevention of Exposure over the Long-term (DISPEL) to Harmful Algal Blooms Cohort Study.

Methods: Between April and June 2021, environmental sampling (water samples), biomonitoring (hand-held spirometry) and participant post-exposure health survey data from the DISPEL cohort was used to characterize health symptoms from exposure to blue-green algae.

Results: Among the 37 enrolled cohort participants (27.0% Florida residents, 70.3% Florida workers, and 2.7% visitors to Florida), two reported post exposure symptoms to blue-green algae, of which headache, cough/choke, itchy skin, and eye redness were the most frequently reported. At baseline, spirometry (FEV1/FVC) results indicated 94.2% of participants had a normal lung function. Across all water samples collected (n=26) by participants near their residential dwellings or occupational areas, 15.4% of samples had detectable levels of microcystin (Figure 1). The four samples with detectable levels of microcystin were collected from DISPEL participants classified as Florida workers. MC-LR, regarded as the most toxic congener, was the most abundant one across all water samples.

Conclusion: Further investigation is needed to characterize the exposure of MC’s, specifically MC-LR among worker groups, and the potential health risks for Floridians in their occupational and residential areas.

Title: Environmentally-Relevant Exposure to Harmful Algal Bloom Toxin Microcystin-LR Compromises Mouse Ovarian Follicle Maturation and Ovulation

Presenter: Yingzheng Wang

Authors: Yingzheng Wang, Pawat Pattarawat, Jiyang Zhang, Eunchong Kim, Ji-Yong Julie Kim, Saurabh Chatterjee, Qiang Zhang, Geoffrey I. Scott, and Shuo Xiao

Abstract: Harmful algal blooms (HABs) caused by elevated water temperatures from climate change and anthropogenic eutrophication have become a global environmental and public health concern. HABs-produced toxins can result in adverse health effects. Humans can be exposed to HAB toxins through seafood, drinking water, and recreational activities. Microcystin-LR (MC-LR), the most common and hazardous type of HAB toxin, has been reported to induce neurotoxicity, hepatotoxicity, and carcinogenicity. However, the impact of MC-LR on female reproductive health has been scarcely studied. The present study aimed to investigate the ovarian toxic effects and mechanisms of MC-LR. We first used a mouse superovulation model to determine whether MC-LR can accumulate in the ovary and affect the gonadotropin-dependent ovarian follicle maturation and ovulation. Twenty-one-day-old CD-1 female mice were intraperitoneally injected daily with vehicle (1xPBS) or 10 μg/kg MC-LR during follicle maturation window only (4-day injection), ovulation window only (1-day injection), or both follicle maturation and ovulation windows (5-day injection). Immunohistochemistry results showed that MC-LR was detectable in ovarian stroma cells, thecal cells of secondary and antral follicles, and granulosa cells of antral follicles. Ovulation induction results showed that exposure to MC-LR during both follicle maturation and ovulation windows significantly decreased the numbers of ovulated oocytes (25.1 ± 10.1 vs 38.0 ± 7.8). However, MC-LR treatment during ovulation window only did not affect ovulation (41.7 ± 3.1 vs 39.8 ± 2.8), but exposure to MC-LR during follicle maturation window only significantly inhibited ovulation (23.1 ± 2.9 vs 36.1 ± 4.0). For mice treated with MC-LR during the follicle maturation window only, histological staining results showed that there were more unruptured preovulatory follicles in MC-LR treated ovaries after ovulation induction (15.8 ± 3.9 vs 9.3 ± 1.9). These results indicate that MC-LR compromises ovulation through disrupting gonadotropin-dependent follicle maturation. To further determine the molecular mechanisms of MC-LR-induced defective follicle maturation, preovulatory follicles were next isolated from vehicle- or 10 μg/kg MC-LR-treated mice for RNA sequencing. There were 753 down-regulated and 266 up-regulated genes in MC-LR treated follicles compared to the control group. Gene ontology analysis revealed that differentially expressed genes were related to vasculature development and angiogenesis. KEGG pathway analysis showed that MAPK, FoxO, and PI3K-Akt signaling pathways were significantly enriched. In addition, we used isolated preovulatory follicles to perform single-follicle RT-qPCR and found that MC-LR treatment decreased the expression of several follicle maturation signature genes, including Pappa, Inha, and Lhcgr. Using our established 3D encapsulated in vitro follicle growth (eIVFG) model, the single-follicle RT-qPCR results showed that 10 μM MC-LR consistently decreased the expression of these follicle maturation-related genes in vitro, indicating the direct effects of MC-LR on follicles. Furthermore, in vitro follicle ovulation assay revealed that the expression of luteinizing hormone (LH)-induced ovulatory genes (Pgr, Areg, Ereg, Btc, Ptgs2, Tnfaip6, Plau, and Runx1) was significantly decreased in MC-LR treated follicles compared to the control group, confirming that the defective follicle maturation caused by exposure to MC-LR affected following ovulation events. Taken together, our studies demonstrate that environmentally-relevant exposure to HAB toxin MC-LR compromises gonadotropin-dependent ovarian follicle maturation and ovulation in mice.

Title: Global Prediction of Vibrios: Correlating Environmental Factors and Vibrio in Chesapeake Bay

Presenter: Mayank Gangwar

Authors: Mayank Gangwar, Moiz Usmani, Yusuf Jamal, Kyle D. Brumfield, Anwar Huq, Rita R. Colwell, Antarpreet Jutla

Abstract: Pathogenic Vibrio species, namely Vibrio cholerae, Vibrio parahaemolyticus, and Vibrio vulnificus, represent a significant and growing threat to human health. V. cholerae is the causative agent of cholera, and with the seventh pandemics[1] and causes approximately 95,000 deaths annually in countries where the disease is endemic[2]. V. parahaemolyticus and V. vulnificus infections, obtained primarily through consumption of raw seafood and direct water contact containing the bacteria, are responsible for more than 34,000 infections and an economic burden of approximately $360 million in the United States annually[3]. Changes in climate and social factors may increase the risk of Vibrio infections in future. The incidence of Vibrio infections in the United States, where dedicated surveillance systems like FoodNet and COVIS exist, are steadily increasing over years. While global incidences of Vibrio infections are difficult to track due to the lack of a coordinated surveillance system, Vibrio infections have been identified where they had never posed an issue such as infections are being detected in regions as far as Alaska[4] and the Baltic Sea[5].

The question remains, “how to identify vulnerable regions of Vibrio spp.?” Early warning systems likely hold promise in allowing decision making protocols to reduce impacts from Vibrio infections. Predictive models, like NOAA CoastWatch product & ECDC Vibrio Viewer currently exist for portions of the United States and for the Baltic Sea, are limited in their coverage. Existing models incorporate variables such as temperature and salinity; however, with fine scale available datasets, variables such as turbidity, chlorophyll, nutrients, precipitation, sea surface height, and oxygen levels must be incorporated to modeling strategies. Overall, before early warning systems can be implemented operationally on a global scale, research is needed to distinguish between the fundamental ecological niche dictated by the physiology of Vibrio spp. and the regional variabilities that can obscure this niche and produce inconsistent modeling results. In the current study, a field sampling campaign began in April 2019 and will continue until 2022 where Oyster and water samples are being collected from the Chesapeake Bay weekly during the warmer months (June to September) and biweekly rest of the year. Preliminary analysis has established positive correlation of temperature and fecal bacteria with Vibrio spp. Hence, the aim is to develop a predictive model using Ecological niche models (ENM’s) to extrapolate across space or time to predict Vibrio presence and abundance on novel landscapes based on the appropriate choice of environmental data sources will be realized after analyzing the completed sampling campaign. ENM’s can be used to recreate species relationships with the environment to identify unexplored areas in geography where these species might be present. The model will aimed towards predicting Vibrio spp. and their associated risk on a global scale to address outbreaks, prevent epidemics, improve coastal resiliency, and anticipate climate change impact on Vibrio range, transmission season and risk[5].

[1] R. R. Colwell, “Global Climate and Infectious Disease: The Cholera Paradigm,” Science, vol. 274, no. 5295, pp. 2025–2031, Dec. 1996, doi: 10.1126/science.274.5295.2025.

[2] M. Ali, A. R. Nelson, A. L. Lopez, and D. A. Sack, “Updated Global Burden of Cholera in Endemic Countries,” PLoS Negl Trop Dis, vol. 9, no. 6, p. e0003832, Jun. 2015, doi: 10.1371/journal.pntd.0003832.

[3] B. A. Muhling, J. Jacobs, C. A. Stock, C. F. Gaitan, and V. S. Saba, “Projections of the future occurrence, distribution, and seasonality of three Vibrio species in the Chesapeake Bay under a high‐emission climate change scenario,” GeoHealth, vol. 1, no. 7, pp. 278–296, Sep. 2017, doi: 10.1002/2017GH000089.

[4] J. B. McLaughlin et al., “Outbreak of Vibrio parahaemolyticus Gastroenteritis Associated with Alaskan Oysters,” N Engl J Med, vol. 353, no. 14, pp. 1463–1470, Oct. 2005, doi: 10.1056/NEJMoa051594.

[5] J. C. Semenza et al., “Environmental Suitability of Vibrio Infections in a Warming Climate: An Early Warning System,” Environ Health Perspect, vol. 125, no. 10, p. 107004, Oct. 2017, doi: 10.1289/EHP2198.

Title: The WHOI HABhub: an online portal for integration and real-time sharing of HAB surveillance data

Presenter: Mindy Richlen

Authors: Mindy Richlen, Michael Brosnahan, Ethan Andrews, Claire Anacreon, Kali Horn

Abstract: Coastal regions in the northeastern U.S. support extensive shellfisheries and fisheries that are heavily utilized by both recreational and commercial harvesters. This region has a long history of recurring regional-scale blooms of Alexandrium catenella, which can cause paralytic shellfish poisoning (PSP). Toxic blooms of Pseudo-nitzschia, which produce domoic acid and cause amnesic shellfish poisoning, are also a more recent phenomenon in New England waters, as are blooms of Dinophysis and Karenia mikimotoi. The emergence of these new species and syndromes has challenged resource managers, who are now faced with monitoring for multiple taxa and toxins year round and developing decision-making approaches for new HAB phenomena. The WHCOHH Community Engagement Core is addressing this problem through development of the WHOI HABhub, an open source, online data portal for region-scale integration and sharing of a variety of different HAB data from multiple sources, including shellfish toxicity observations, sensor observations, and shellfish closure actions, as well as HAB forecasts and other model products. Data analysis pipelines have been constructed to interpret and display raw sensor outputs, while providing users the ability to access instrument dashboards and export data through the portal’s interface. When complete, the HABhub will enable real-time access to taxa and toxin data collected through a region scale network of advanced HAB sensors called NHABON-NE. The system aims to provide early warning and better situational awareness regarding the dynamics of multiple HAB taxa across the region and over multiple seasons. Resource managers and stakeholders are engaged during development of prototype map layers to share observations and capabilities, and to solicit their input, feedback and collaboration. The HABhub is being developed an open-source project for broad adoption by other HAB monitoring groups. As part of our documentation effort, we are currently exploring options to pilot the data portal in other regions of the U.S. and abroad.

Title: A Community Engagement Framework for Oceans and Human Health

Presenter: Maggie Carson and Louisa Schandera

Authors: Maggie Carson, Diane M. Doberneck, Zac Hart, Heath Kelsey, Dwayne E. Porter, Mindy Richlen, Louisa Schandera, and Heather Triezenberg

Abstract: The Oceans and Human Health (OHH) field includes a variety of disciplines and applications, and has evolved extensively over the past two decades. With the growing investment in the importance of partners, communities, and other stakeholder involvement in OHH research, the most recent National Science Foundation (NSF) and National Institute of Environmental Health Sciences (NIEHS) OHH Centers included community engagement as a core element of the Center model. The 2019 NSF/NIEHS joint Center meeting focused on community engagement and initiated development of a proposed strategic framework for OHH community engagement (Figure 1). Foundational to the framework is to make the intentional connection among partners, purpose, activity, and approach. Partners refers to the agency, tribe, community, or other groups, with specific attention to non-traditional partners, that an activity seeks to engage OHH activities with or for. Identifying why doing activities with a partner will clarify the purpose and avoid confusion or conflict. The available activities for partner use or co-creation of OHH activities are vast, including research (including community science), formal and informal education, policy, management, communications, public health, clinical practice. The approach represents a spectrum of degree of participation ranging from outreach and one-way communication on one end, to full engagement involving multi-way communication on another end. For example, some efforts might be more aligned to outreach (e.g., public health alerts or science communication to inform a specific group) depending on the partners’ needs and purpose. At the other end of the spectrum are engagement approaches (e.g., working with partners to collaborate on development of a policy or co-create a community science program). Without the intentional alignment of those four elements, confusion, conflicts, or limited impact of OHH activities are likely to occur.

Title: Assessing Stakeholder Needs and Preferences for Coastal Swimming Advisories in Charleston, South Carolina

Presenter: Zac Hart

Authors:

Abstract: Although the BEACH Act of 2000 established a solid framework for protecting the public from waterborne pathogens at beaches, inland coastal waterways such as rivers, creeks, and harbors generally do not experience the same level of rigor with respect to monitoring, reporting, and public notification when threats exist. In many coastal areas, this represents a growing public health risk, as coastal population growth paired with expanding recreational use of coastal waters results in more individuals entering the water. In locations such as Charleston, South Carolina, community-based organizations like the Charleston Waterkeeper have formed to address this risk communication void and to supplement the work of state agencies who conduct routine water quality monitoring at popular beaches. While the data furnished by the Charleston Waterkeeper meets widely accepted standards and is freely available to the public, it currently cannot be used as the basis for state-issued swimming advisories that direct users to avoid swimming at specific locations until conditions are safe. The lack of an official warning system related to pathogens in these popular natural resources underscores the hazard posed by human pathogens in coastal waterways.

An online survey of recreational waterway users in Charleston was conducted to assess stakeholders’ awareness of water quality issues as well as their desire to be informed when high levels of pathogens were detected in the water. Among the 143 complete survey responses, 126 (88%) resource users indicated that they were at least “slightly aware” that coastal waters can harbor illness-causing pathogens, and 127 (89%) strongly agreed or agreed that they would want to know if contact with coastal waters could make them ill. The survey also investigated who stakeholders would consider credible sources of water quality messages, and it gathered recommendations on the mode and delivery of water quality messages. While survey respondents indicated that they considered a wide variety of sources to be credible sources of water quality information, 120 (84%) stakeholders expressed a preference for being notified automatically about dangerous conditions in waterways that they use, and 113 (79%) indicated that they would be extremely or moderately likely to enroll in automatic notifications about water quality. This suggests a more proactive approach to notifying resource users, rather than common, more passive approaches in which water quality data are made available online for resource users to seek out.

The project also included ten interviews with the owners or managers of water-dependent businesses in the Charleston area. Interview questions focused on stakeholders’ perceptions of waterway health as well as their use of, and preferences for, water quality data. Eight interviewees expressed either general or site-specific concerns about Charleston water quality, and those same eight interviewees reported at least occasional use of available water quality data to inform their business operations or programming. Additionally, eight interviewees expressed a preference for direct, real-time notification, for example through text messaging, when water quality conditions could pose a risk to themselves and their clients. Interview findings corroborate survey findings, with both suggesting a proactive, automated approach to advisories for those involved in water-based recreation.

Title: EJ Strong: Strengthening Communities for Disaster Risk Reduction, Response & Recovery in South Carolina – An Outreach Project of the OHHC2I Community Engagement Core

Presenter: Zac Hart

Authors: Omar Muhammad, Dwayne E. Porter, Daniel Kilpatrick, Paul A. Sandifer

Graduate student participants: Katya Altman, Kim Jones, Jude Owoh, Judith Taylor

Abstract: EJ Strong is an EPA-funded Community Disaster Risk Reduction initiative developed by the SC Department of Health and Environmental Control (SCDHEC) in collaboration with the Community Engagement Core of our OHHC2I, Clemson University, and the Lowcountry Alliance for Model Communities (LAMC), one of our CEC partners. Through four multi-day immersive workshops and regular webinars over two years, EJ Strong seeks to train leaders in underserved LAMC communities as well as other EJ communities across South Carolina in resilience, disaster risk reduction, and self-assessment. Trainees learn to use tools to assist them in helping their communities cope with hazards and disasters such as hurricanes, chemical releases, and pandemics. By the end of the project, participants will have completed assessments of their community's hazard, capacity, and vulnerability profiles, and will be trained to teach others how to complete such assessments as well. OHHC2I investigators have contributed to workshop and webinar curricula, provided expertise on hazards and human health, and facilitated events as both speakers and organizers to support the initiative's learning objectives, which include identification and prevention of flooding and other environmental and health hazards within communities; development of increased capacity to conduct preparedness, response, recovery, and mitigation; strengthening ability of block captains to mobilize people and resources; and others. Our first workshop was a 2-day in-person event held in one of the LAMC communities on June 25-26, 2021, with >30 participants (Figure 1). This was followed by a hazards assessment instructional webinar on August 25, 2021. Additional webinars and workshops will be held during the remainder of 2021 and 2022. Following the training, the curriculum will be converted into webinars and made available to others. The work is conducted through highly participatory and experiential learning exercises based in part on the Learn! Leverage! Lead! model used in many of our OHH CEC activities. Graduate students are serving as interns and workshop/webinar facilitators with the EJ community partners.

Title: Building a communication campaign about Harmful Algal blooms for vulnerable populations in Freshwater Lakes in Michigan

Presenter: Alexandra Benitez

Authors: Alexandra Benitez, Dr. Heather Triezenberg, Dr. Abigail Bennet & Dr. Mark Rey

Abstract: Freshwater Harmful Algal Blooms (HABs) are a growing concern in Michigan, and they are shown to cause adverse human health effects when exposed directly. Currently, there is limited information regarding the human health effects caused by HABs especially for vulnerable populations who have a higher predisposition for receiving medical care if exposed directly to HABs. This two-phase study aimed to develop a communication campaign to raise awareness about HABs’ health effects and their vulnerable population in freshwater lakes in Michigan. The study selected three lakes due to their high levels of microcystin and HABs outbreaks since 2017, Lake Erie, Belleville Lake and Ford Lake, and explored the participant’s personal lake experience, communication preferences, and current knowledge about HABs and its potential health effects through phone interviews. By learning about their lake experiences and communication preferences among the different lakes, we plan to analyze using qualitative data analysis through NVIVO, apply Social Amplification Risk Factor (SARF) Framework and grounded theory methodology to determine emerging themes and create a communication product. For the second phase of our study, we plan to launch focus groups for each lake and evaluate it’s efficacy using a pre and post-test evaluation form. The selected vulnerable population for this study included residents near the lakes, elderly population (65+), and those with pre-existing conditions such as chronic kidney disease, diabetes, cancer patients, asthma, pre-existing liver conditions, and dialysis patients. The study found most participants were unaware of HABs negative impacts and its potential health effects, by creating this product the study plans to include the selected vulnerable populations personal communication preferences to improve how HABs are currently being communicated by increasing its awareness during the summertime, where they are shown to be more predominant.

Title: Where The Seawall Ends: A Participatory and Spatial Analysis of Potential Impacts of the Proposed Charleston Battery Seawall on Upper Peninsula Environmental Justice Communities

Presenter: Judith Taylor

Authors: Judith Taylor, Paul A. Sandifer, Dwayne E. Porter, and Omar Muhammad

Abstract: The city of Charleston, SC, and its surrounding areas are experiencing rapid increases in tidal and storm surge flooding, resulting in mounting impediments to regular traffic and business and rising concerns about potential exposures of residents and visitors to mold, infectious disease organisms, chemical pollutants, and harmful algal bloom toxins (Brusee 2020, Petersen and Porter 2020). In response to threats of sea level rise and storm surge posed by climate change, the City of Charleston and the U.S. Army Corps of Engineers (USACE) have proposed a 9-mile-long, 12-feet-tall seawall to be constructed around parts of the downtown Charleston peninsula. The seawall will terminate in the neck of the peninsula, close to several lower wealth communities that contain high populations of minorities. Potential impacts to these communities were not initially considered by USACE or the City of Charleston, despite documented instances of detrimental effects of seawalls on biodiversity, erosion, and adjacent property values. This study seeks to fill this information gap using knowledge co-production and community participatory approaches. Community input and knowledge are being collected via conversations and semi-structured interviews with community residents and leaders and with flooding/resilience experts from the cities of Charleston, North Charleston, the USACE, the SC Sea Grant Consortium, and the Charleston Resilience Network. Following this information collection phase, GIS technology will be used to visualize key potential impacts identified by participants and analyze how the seawall might affect flooding, potential exposures to harmful organisms and substances, erosion, and biodiversity in the project area. The project is related to the EJ Strong Disaster Risk Reduction effort of the OHHC2I CEC, with the primary focus being the eight EJ communities that comprise the Lowcountry Alliance for Model Communities, all of which are located near the terminus of the proposed seawall (Figure 1 A, B). Results will be compiled into a written report, an ArcGIS Story Map, and conveyed in interactive community meetings, and will provide a usable, community-owned environmental justice perspective on this major project.

References:

Brussee, B. 2020. “Rising Waters: Fixed for Failure.” The Post and Courier, 21 May, p. A5.

Petersen, B., Porter, M. 2020. https://www.postandcourier.com/news/charleston-and-the-south-carolina-coast-flooded-record-89-times-in-2019/article_7c18ee5e-2e3b-11ea-8784-23ddbc8d4e0c.html.

Figure 1. A. Maps of the Charleston peninsula showing the location of the proposed sea wall (red line encircling the peninsula). B. Location of the eight EJ communities that may be affected.

Title: OHH Community Engagement Cores as Boundary Spanners: What a Qualitative Study of OHHC2I Environmental Health Partners’ Communication Practices and Needs Tells us about Effective Research Translation and Science Communication.

Presenter: Katya Altman

Authors: Katya Altman, Brooks Yelton, Hildehardo F. Viado, Jr., Margaret A. Carson, Louisa Schandera, R. Heath Kelsey, Dwayne E. Porter, Daniela B. Friedman

Abstract: Boundary-spanning work that involves interdisciplinary partners is gaining attention as necessary to sustain such relations for improved environmental health outcomes. Boundary spanners meaningfully connect organizations’ internal communications with external ones to enrich both; however, such work requires a certain set of skills and experiences to sustain bi-directional communication with partners. The Center for Oceans and Human Health and Climate Change Interactions (OHHC2I) Community Engagement Core (CEC) conducted a qualitative study with Center partners to examine their science communication practices and needs with the ultimate goal of informing a collaborative training and improve stakeholder-scientist partnerships. The CEC researchers used purposive (intentional) and snowball (referral-based) sampling to invite partners to participate. Thirteen (13) individuals participated in 10 semi-structured qualitative interviews focused on their research translation needs, science communication and dissemination tactics, and interactions and experiences with scientists. The authors employed a hybrid approach to semantic thematic analysis, using both deductive and inductive coding for themes. Interviewees described their work and environmental health focus areas, and six main categories of themes emerged: 1) communication practices, 2) communication challenges, 3) perceptions of research translation, 4) communicating about uncertainty, 5) collaboration with scientists, and 6) training in research translation and science communication. Based on our findings, we recommend a collaborative, scientist-stakeholder training to include plain language development, dissemination tactics, communication evaluation, stakeholder and intended audience engagement, and strategies for effective transdisciplinary partnerships. This work contributes new knowledge and understanding of stakeholder engagement practices specifically focused on science communication that can enhance relationships building between academia and partners involved in environmental health-focused initiatives. In addition, academia and practitioners will benefit from learning about environmental health partners’ preferences and successful practices for interacting with scientists and translating scientific research into useful applications in the context of South Carolina but applicable elsewhere.

Title: Informed Community Engagement through Assessment of Science Communication and Research Translation Practices and Needs in a Coastal Community in South Carolina.

Presenter: Katya Altman

Authors: Katya Altman, Geoff I. Scott, R. Heath Kelsey, Susan Libes, Dwayne E. Porter.

Abstract: The primary focus of this research is on developing sustained partnerships between scientists and stakeholders to facilitate science communication and research translation of scientific results on a local level. This research aims to analyze science communication and research translation experiences, practices, and needs in the context of water quality and environmental health in the coastal community of Murrells Inlet, SC. Qualitative semi-structured interviews with 13 community leaders were conducted. The recorded transcripts were analyzed for emergent themes using NVivo 12, a qualitative data management and analysis software package, using a hybrid approach to semantic thematic analysis. Results show that coastal stakeholders have multiple intended audiences for their communication (decision-makers, people based on a geographic location, people based on their activities, and industry); use multi-media approaches to reach their audiences (social media, websites/newsletters, meetings/events, local media, and others), and mostly lack formal training in science communication and research translation. Participants also outlined communication barriers and shared best practices that help to bridge the gap between public understanding and scientific knowledge. This research enhances the understanding of community needs in science communication and research translation in a context of a coastal community in South Carolina to better facilitate bi-directional communication between researchers and stakeholders.

Title: CiguaMOD: a base model to predict Gambierdiscus cell densities and algal toxin loadings in St. Thomas coastal waters, USVI.

Presenter: Michael L. Parsons

Authors: Michael L. Parsons, Mindy L. Richlen, Tyler B. Smith, Alison Robertson

Abstract: Ciguatera poisoning (CP) is the most common form of phycotoxin-related seafood illness and is thought to be caused toxins that originate in species of the benthic, epiphytic dinoflagellate genus, Gambierdiscus. CP incidences often wax and wane over time, hypothetically in response to increases and decreases in Gambierdiscus densities, particularly those species capable of producing significant amounts of toxin. A significant hurdle in the development of management strategies to monitor for and limit exposure to CP is the inability to predict such outbreaks. Here, we present a version of our ciguatera model (CiguaMOD) that simulates the densities of Gambierdiscus cells on host algae they grow epiphytically on (Dictyota) in response to seasonal changes in temperature, wave action, and light intensity at four reefs sites along the south coast of St. Thomas (U.S. Virgin Islands). Toxin loads were then estimated from the resultant cell densities growing on host algae. Validation of the model was then evaluated by comparing the simulated results with actual field-based measurements of cell densities and toxin loads. This model represents an important next step in development with the incorporation of the toxin loading validation step.

Title: Modeling the future of harmful cyanobacterial blooms in an anthropogenically-altered world

Presenter: Michael L. Parsons

Authors: J. Thad Scott, Nicole Wagner, Scott C. James, and Bryan W. Brooks

Abstract: Human-induced climate and landscape change may be increasing the frequency and magnitude of harmful cyanobacteria blooms and their toxin(s) production. Increased temperatures and dissolved inorganic carbon dioxide availability caused by climate change, as well as altered hydrology and nutrient loading regimes caused by landscape change can have a direct influence on the growth and toxin production by cyanobacteria. We are working to develop robust forecasting tools that will provide a means for prevention and early-detection/mitigation of these blooms. To meet this objective, we are conducting small-scale laboratory experiments to quantify the mechanisms of bloom development and variable neurotoxin and hepatotoxin production. These experiments have identified nutritional stoichiometry as a major driver of both bloom formation and toxin production. We are applying these findings to larger-scale field experiments to develop real-world simulations of potential bloom-forming conditions. Collectively, this research is informing the development of mathematical models that can utilize readily available inputs to forecast cyanobacterial blooms. To date, we have developed two simple models that utilize cyanbobacterial nitrogen and phosphorus stoichiometry and dissolved nitrogen uptake kinetics to simulate growth and toxin formation. The goal of this research is to transfer these models into inland and coastal ecosystem simulations to provide either short-term iterative forecasts and/or long-term risk assessments.

Title: Modeling the future of harmful cyanobacterial blooms in an anthropogenically-altered world

Presenter: J. Thad Scott

Authors: J. Thad Scott, Nicole Wagner, Scott C. James, and Bryan W. Brooks

Abstract: Human-induced climate and landscape change may be increasing the frequency and magnitude of harmful cyanobacteria blooms and their toxin(s) production. Increased temperatures and dissolved inorganic carbon dioxide availability caused by climate change, as well as altered hydrology and nutrient loading regimes caused by landscape change can have a direct influence on the growth and toxin production by cyanobacteria. We are working to develop robust forecasting tools that will provide a means for prevention and early-detection/mitigation of these blooms. To meet this objective, we are conducting small-scale laboratory experiments to quantify the mechanisms of bloom development and variable neurotoxin and hepatotoxin production. These experiments have identified nutritional stoichiometry as a major driver of both bloom formation and toxin production. We are applying these findings to larger-scale field experiments to develop real-world simulations of potential bloom-forming conditions. Collectively, this research is informing the development of mathematical models that can utilize readily available inputs to forecast cyanobacterial blooms. To date, we have developed two simple models that utilize cyanbobacterial nitrogen and phosphorus stoichiometry and dissolved nitrogen uptake kinetics to simulate growth and toxin formation. The goal of this research is to transfer these models into inland and coastal ecosystem simulations to provide either short-term iterative forecasts and/or long-term risk assessments.

Title: Potential effects of climate change on Pseudo-nitzschia in the Gulf of Maine

Presenter: Suzanna Clark

Authors: Suzanna Clark, Michael Alexander, Katherine A. Hubbard, Dennis J. McGillicuddy, Jr., David K. Ralston, Charles Stock

Abstract: Pseudo-nitzschia blooms have been connected to anomalously warm ocean temperatures, and P. australis domoic acid production has been shown to increase with temperature, suggesting that Pseudo-nitzschia blooms might intensify with climate change. In the Gulf of Maine in 2016, a regionally novel domoic acid event caused by P. australis coincided with a marine heatwave, prompting the investigation of Pseudo-nitzschia bloom dynamics in the region. In this study, climate simulations were dynamically downscaled to a 1-3 km model in the Gulf of Maine to project the potential impacts of climate change on Pseudo-nitzschia blooms in the region. Climate simulations were run for 25 years at the beginning and end of the 21st Century. Sea surface temperatures in the region are projected to increase by 2°C on average, with the largest increase occurring in the late summer. Based on a temperature growth curve for P. australis derived from laboratory studies, increasing temperatures could shift P. australis bloom timing 2-3 weeks earlier in the spring and 3-5 weeks later in the fall. The P. australis growing season is also projected to increase by 3 weeks in the Bay of Fundy and eastern Gulf of Maine, where historic domoic acid-induced shellfishery closures have occurred. In addition, inflows from the Scotian Shelf are projected to strengthen relative to inflows from the Northeast Channel, and alongshore transport along the coast of Maine is expected to weaken in the winter and spring but strengthen in the summer and fall. These changes combined suggest that P. australis blooms might intensify in the eastern Gulf of Maine toward the end of the 21st Century. More work is necessary to put temperature and physical changes into an ecological context, and to explore potentially limiting factors such as nutrient availability.

Title: Complex mechanistic (and simple empirical) models predict planned P load reduction will make Lake Erie more toxic

Presenter: Ferdi L. Hellweger

Authors: Ferdi L. Hellweger, Robbie M. Martin, Falk Eigemann, Steven W. Wilhelm

Abstract: Harmful cyanobacteria are a critical environmental problem, yet we lack actionable understanding of toxigenic vs. non-toxigenic strain ecology and toxin production. We performed a large-scale meta-analysis that included 103 papers totaling 708 experiments, and used these to develop a dynamic, mechanistic, molecular-level agent-based model of Microcystis growth and toxin production. Simulations for Lake Erie suggest the observed strain succession during the 2014 Toledo drinking water crisis was controlled by different cellular reactive oxygen damage mitigation strategies, and their different susceptibility to nitrogen limitation. The model, as well as a simpler empirical one based on linear combination of mechanisms, predict that planned P-load reduction will lower biomass, but make N and light more available, which will favor toxigenic cells and increase microcystin concentrations.

Title: Tracing and tracking infectious pathogens in coastal waters

Presenter: Antar Jutla

Authors: Antar Jutla, Rita Colwell and Anwar Huq

Abstract: More than 50% of global human population lives within 50 miles of the coasts. Unfortunately, several pathogens (e.g., cholera, shigella, rotavirus) are frequently reported in coastal regions of the developing world. Water‐related diarrheal diseases remain second leading cause of child death worldwide, killing over 1.5 million children annually and infecting millions more. These diseases (and thus pathogens) are not likely to be eradicated since the disease‐ causing agents are always present and adapt to environment. Climate change and intensification of severe weather eventsis likely to increase sea level, and is expected to make flooding or drought uncertain along the coastal regions. Given the complex nature of interaction between coastal ecology, human behavior, climate and diarrheal disease, it is important to have a holistic approach to understand mechanisms of outbreak and transmission of such pathogens along the coasts. Using data collected from several coastal regions, we will provide a framework and an adaptive model that determines ecological niches of pathogenic vibrios in coastal waters. The model is capable to run scenarios under various climate change conditions. Figure 1 shows the implementation of an ecological niche model outputs for niches of vibrios along coastal locations of the world. Satellite data sources have been mostly preferred for environmental data e.g. combined rainfall data from TRMM and GPM, seas surface temperature data and Chlorophyll Concentration anomalies from MODIS satellite, salinity data from Aquarius satellite have been used. International Hydrographic Organization (IHO) and Intergovernmental Oceanographic Commission (IOC) collected bathymetry data have also been used. The outcome global vibrio risk map enables both general public and health profession to be aware of the suitable habitat of vibrio species along the coast.

Title: Comparing Alexandrium catenella cyst germination rates through degree-day-based modeling of rate distributions

Presenter: Alexis D. Fischer

Authors: Alexis D. Fischer & Michael L. Brosnahan

Abstract: Blooms of many dinoflagellates, including several harmful algal bloom species, are seeded and revived through germination of benthic resting cysts. Temperature is a key determinant of the germination rate, and temperature–rate relationships are therefore fundamental to understanding cyst bed persistence and germling cell production. Rate differences within and between populations reflect their ability to adapt and/or acclimate to environmental change. In this study, we show how results from sediment slurry germination experiments with different, naturally occurring Alexandrium catenella cyst populations can be compared using heating degree-days (DDs; a metric which uses temperature and time). For any given population, the median days until germination decreases hyperbolically with increasing temperature. DD scaling collapses differences across temperatures and produces consistent rate distributions within a population (Fig. 1). This enables comparisons of temperature–rate relationships measured at different incubation temperatures through maximum likelihood estimation of three population-specific parameters: critical temperature, DD requirement, and DD requirement variance. In an initial application of this model, we show that cysts from Puget Sound (WA) germination times are shorter and have substantially less variance than cysts from the Nauset Marsh estuary (Cape Cod, MA). Faster germination by the Puget Sound population may be favorable in a habitat that experiences short, unpredictable windows for bloom initiation. Whether these population differences are rooted in genetic selection or phenotypic plasticity is unknown, but are a topic of future investigation. This research provides a framework for comparing germination by different naturally-occurring populations and examining how A. catenella may respond to a changing climate.

Title: Use of growth models to diagnose the cause of a harmful cyanobacterial bloom

Presenter: Samuel P. Putnam

Authors: Samuel P. Putnam, Tryston T. Metz, Cassidy A. Crandell, Timothy J. Shaw, John. L Ferry*

Abstract: Models of harmful cyanobacterial blooms (HCBs) in freshwater environments can be used to predict the growth of biomass or to diagnose the cause of a bloom. Here we apply a series of diagnostic models to show that legacy phosphorus in sediments is the main driver of a benthic HCB of Lyngbya wollei. Surveys performed by the University of South Carolina working with local citizen science groups identified a series of over 200 blooms of Lyngbya wollei persistent in Lake Wateree, SC. An estimated 5.2 x 106 kg of biomass was observed in the lake, occurring under nutrient loading in the water column that was near or below total maximum daily load (TMDL) guidelines for phosphorus and nitrogen. A series of established predictive models of cyanobacterial biomass were applied as a diagnostic to determine the cause of the HCB. Sedimentary phosphorus loading was found to be the only variable that gave a statistically significant biomass as compared to field observations. Historical records of water column phosphorous measurements show that an average of 1.67 x 105 kg of phosphorous per year are removed from the lake as the river channel flows through. The sediments of the lake can be lifted by bubble of gasses entrained in the algal mat, providing a source of phosphorous accumulated by sediments over time. This legacy phosphorous in the sediments gives a powerful diagnostic tool for predicting the biomass potential of an HCB.

Title: Human Dietary Exposure to Microplastics from Oysters (Crassostrea virginica): Lowering Exposure through Depuration

Presenter: Bonnie Ertel

Authors: Bonnie Ertel, Brooke Blosser, Dr. John Weinstein

Abstract: Microplastics (MP) have been documented in numerous seafood species, including filter-feeding organisms such as the Eastern oyster (Crassostrea virginica). In South Carolina, oysters are a commercially and ecologically important species frequently consumed by humans at backyard oyster roasts and restaurants alike. Previous research suggests shellfish can reduce their load of environmental contaminants when given a depuration period in clean seawater. The objective of this research was to quantify human dietary exposure to MP particles due to consumption of local oysters, and to determine if a depuration period is an effective method to reduce MP contamination. Oysters (n=298) surveyed from 9 state-managed commercial and recreational harvesting grounds and one reference location in South Carolina contained an average of 19.9±10.6 MP per individual, of which 59.4% were fibers, 21.3% were suspected tire wear particles (TWP), and 12.8% were fragments. These results suggest that a single serving of local oysters (one dozen) contains on average 238.8±127.2 MP, which is 5x more MP than a typical meal. In the laboratory, oysters were exposed for 96-h to either polyethylene fibers, nylon fragments, or micronized crumb rubber as a surrogate for TWP, then provided a subsequent depuration period in MP-free water and sacrificed at 0, 24, 48, and 96-h. After 96-h of exposure, oysters contained an average of 12.9 (±2.7 SE) fibers, 3.11 (±0.56 SE) fragments, and 20.6 (±3.9 SE) crumb rubber particles per individual. Following 96-h of depuration, MP fiber abundance was reduced by 72% to 3.6 fibers/oyster, fragment abundance was reduced by 87% to 0.38 fragments/oyster, and crumb rubber was reduced by 53% to 9.7 TWP/oyster. The present study suggests that providing oysters a depuration period could reduce human dietary MP exposure.