Research

Clark's Marsh: PFAS in aquatic food webs

Purdue University | Michigan DNR | Michigan EGLE | Purdue's Center for the Environment

Per- and Polyfluoroalkyl Substances, or PFAS, are synthetic chemicals of emerging concern. This project examines PFAS distribution and movement in an aquatic food web impacted by PFAS (Clark’s Marsh Wildlife Area, Oscoda, MI). Our goals are to 1) develop conceptual ecosystem model describing food web structure and PFAS exposure routes, 2) quantify the bioaccumulation of 24 unique PFAS in aquatic and semi-aquatic plant and animal species, and 3) determine bioaccumulation and biomagnification factors for each PFAS. The results of our work will greatly improve our understanding of the impact of PFAS on aquatic food webs and sources of PFAS flux to terrestrial ecosystems.

The Relative Toxicities of Current Use Aqueous Film Forming Foams and Next Generation Alternatives to Aquatic Species for Informing Risk Assessment

Purdue University | Department of Defense

Given the widespread contamination, persistence, and environmental impacts associated with the use of aqueous film forming foams (AFFF) containing per- and polyfluoroalkyl substances (PFAS), there is a need to develop PFAS-free foam alternatives to replace old technologies in fire-suppression operations. However, before the selection and implementation of fluorine-free foam alternatives, research must address their potential environmental impacts. In 2020, we were funded by SERDP to assess the relative toxicity of AFFF alternatives to aquatic species. For this project, we are conducting controlled laboratory experiments with zooplankton (water fleas, Daphnia magna), fish (fathead minnows, Pimephales promelas), and larval amphibians.

Factors that predict prevalence of ophidiomycosis in the brown watersnake (Nerodia taxispilota)

UGA SREL | UI Wildlife Epidemiology Lab | Riverbanks Zoo & Garden

Snakes are declining globally, and their populations are threatened by habitat loss, climate change, invasive species, and disease. In the last two decades, ophidiomycosis (also known as snake fungal disease [SFD]) has emerged as a threat to snake populations in the United States. While we have learned much recently about the distribution of SFD in southeastern snake species, little is known about what factors (e.g., sex, season, immune status) drive infection. The goals of this study were to determine prevalence of SFD in a common watersnake species in the southeast, as well as evaluate how age, season, sex, immune status, and contaminant concentrations may impact SFD prevalence.

Adapting and optimizing immunoassay techniques in watersnakes (Nerodia spp.)

UGA SREL | U.S. Department of Energy

Compared to mammalian and avian species, knowledge of the reptilian immune system is greatly lacking, especially in snakes. Further, even less is known about the impact of environmental contaminants on snake immunity. This gap in knowledge is largely due to an absence of established immune-based assays or specific reagents for these species. The goal of these studies was to optimize a mammalian in vitro immunoassay to evaluate immunotoxicity of certain contaminants. These results are informative and should provide risk assessors with a better understanding of how contaminants, such as mercury, may impact the snake immune response.

Watersnakes (Nerodia spp.) as biomarkers of contamination

UGA SREL | U.S. Department of Energy

Although ecological risk assessments encompass a variety of taxa, reptiles are commonly underrepresented in these studies. Furthermore, snakes are widely excluded from ecotoxicological studies, regardless of their life history characteristics. The overarching goal of this study was to explore the utility of watersnakes (Nerodia spp.) as receptor species for mercury (Hg) and radiocesium (137Cs) contamination in the Savannah River Site area. Watersnakes, such as the brown watersnake (N. taxispilota) can be top predators in aquatic systems, with a diet consisting primarily fish. These data will improve our understanding of contaminant dynamics in reptiles, increase inclusion of these species in risk assessments, and as provide a foundation for further monitoring with Nerodia spp. in aquatic systems in the southeastern U.S.

Physiological characteristics of reptiles that mediate variation in response to drought

UGA SREL | U.S. Army Corps of Engineers

Predicted climatic conditions in the southeastern USA are defined by increasing periods of drought, higher temperatures, and greater seasonal stochasticity. The ability of an organism to physiologically tolerate changing condition has evolved over long periods of time and limits the ability of many species to effectively adapt to a rapidly changing climate. Many reptile species are threatened by climate change and also exhibit physiological characteristics (e.g., significant metabolic maintenance costs relative to other taxa) that make them vulnerable to a quickly changing climate. The goals of this study were to perform lab experiments to provide novel information (e.g., metabolic rates, evaporative water loss trials) for determining physiological thresholds for aquatic and semi-aquatic reptile species that may be more sensitive to drought.

Effects of coal combustion residues in the yellow-bellied slider (Trachemys scripta scripta)

UGA SREL | U.S. Department of Energy

Freshwater turtles are at increased risk for extinction, and although they have been shown to accumulate large amounts of pollutants, little is known how contaminants affect their immune status and overall health. Coal combustion residues (CCRs) contain high amounts of potentially toxic trace elements and are known to cause metabolic aberrations and histopathological abnormalities in some reptilian species. The studies performed for this project aimed to understand how CCR trace elements accumulate and impact the health (through ecoimmunological methods) of wild T. scripta. In addition, we investigated how a common CCR trace element, selenium, impacted this species in a controlled lab study.

Small mammal prey base for American marten (Martes americana) within the Manistee National Forest of Michigan

Maryville College | Grand Valley State University | Little River Band of Ottawa Indians

American martens (Martes americana) are typically found in late-successional forests with closed canopy cover and high structural diversity. Reintroduced populations of martens in the Northern Lower Peninsula of Michigan inhabit areas that are devoid of many of these features, which may impact their prey base. The goal of this study was to evaluate the small mammal prey base available to martens in the Northern Lower Peninsula. To assess prey availability, diversity, and composition, as well as effects of trap type and habitat features on trapping success, we sampled 24 study plots within the Manistee National Forest for small mammals in the summers of 2013 and 2014.