Research
Contaminant-biofilm interactions and environmental justice
The major research themes of the Ikuma lab is contaminant-biofilm interactions and environmental justice.
Environmental biofilms are biologically, chemically, physically, spatially, and temporally extremely heterogeneous at micro-, nano-, and molecular scales. This inherent complexity and heterogeneity translates to difficulty in understanding and controlling the processes driven by biofilms (which include not only biological processes in engineered systems but also the biogeochemical cycling of nutrients), especially when contaminants are involved.
Some research questions that we are tackling are:
- Where do contaminants end up in the biofilm matrix?
- How does the distribution of contaminants affect their fate in biofilms?
- How are biofilm ecology and functions impacted by the presence of contaminants?
- How do mixtures of contaminants behave in biofilm systems?
These research questions will be explored through combinations of experimental setups, instruments, and analyses including but not limited to pure and mixed culture lab experiments, molecular biology tools, metagenomics, metatranscriptomics, metabolomics, and surface-sensitive chemical analyses. In her research and teaching, Dr. Ikuma posits that advancements in environmental microbiology and biotechnology can further environmental justice.
Current research projects:
Accelerating technical and community readiness for beneficial water reuse in small systems
Water reuse is an increasingly important response to water stress; however, major advancements in water reuse have neglected small, rural communities that comprise most public water systems. The objective of this project is to accelerate water reuse adoption in small communities by increasing technical and community readiness. Dr. Ikuma leads an integrated research and engagement program in which knowledge will be co-produced with decision-makers. This project is in collaboration with Drs. Lu Liu, Antonio Arenas, Joe Charbonnet, Chris Rehmann, Say Kee Ong, Yu Wang (ISU), Joe Goodwill, Vinka Craver, Todd Guilfoos (URI), and Michael Kiparsky (UC Berkeley), and is funded by the US EPA through the National Priorities research grant program ($3.25M).
Pathways to exposure to pathogens during floods
Microbial contamination in water—especially after floods—threatens public health in much of the U.S. This project will investigate and quantify pathways for people to be exposed to pathogens during floods. Objectives are to (1) evaluate and compare pathways to exposure in different settings with different types of flooding and sources of contamination, (2) identify processes and mechanisms that lead to recovery from or resilience to the contamination, and (3) identify conditions that lead to vulnerability of various populations. This work will advance knowledge on the effects of flooding, inform efforts to protect public health, and promote environmental justice. This project is in collaboration with Dr. Chris Rehmann (lead PI) at ISU and is funded by the National Institutes of Water Resources (USGS). (Image courtesy of Schlemmer 2020.)
Building resilience in vulnerable older adult communities facing increased exposure risks to wastewater contamination from flooding in Puerto Rico
This research project studies human interactions with contamination risks in communities directly impacted by natural disasters with an emphasis on the vulnerabilities of older adults within the affected communities. The ultimate goal of this project is to increase the resilience of communities with vulnerable older adult populations to future disasters, especially flooding. With increasing severity and frequency of natural disasters that disproportionately affect low-income communities, this project has the potential to have widespread impacts on those most vulnerable in our nation. This project is a collaboration with Drs. Cristina Poleacovschi, Chris Rehmann, Carl Weems (ISU), and Ivis Garcia Zambrana (TAMU), and is funded by the US EPA.
Building adaptive capacity to climate change in Alaska Native communities by reducing health risks from water infrastructure, quality, and security
This study will assess the relationships between diverse climate-induced concerns related to water infrastructure and water and its effects on health in Alaska Native communities. Importantly, the project also aims at building capacity to climate change risks by addressing the issues of water infrastructure in Alaska Native communities. In a holistic manner, this project captures health outcomes based on health indicators and biomarkers, mental health indicators and non-Western perspective of health outcomes. This project is in collaboration with Drs. Cristina Poleacovschi (lead PI), Carl Weems, Scott Feinstein, Christina Hill (ISU), and Lina Sela (UT Austin), and is funded by the US EPA.
Bacterial outcomes of disinfection - tackling viable but nonculturable (VBNC) pathogens and disinfectant resistance
Water disinfection is the final line of defense for public health against pathogens. Even though it has been used for centuries, the exact inactivation mechanisms of disinfection are yet to be fully deciphered. In particular, disinfection tends to form viable but nonculturable (VBNC) bacteria who have not lost their virulence. Our observations imply that bacteria can further form resistance to disinfectants through altering such VBNC outcomes. These disinfection outcomes in bacteria much be further elucidated to protect public health, especially with increasing interests in water reuse.
Predicting the fate and transport of antibiotic resistance genes in streams
The aquatic environment can act as a reservoir for antibiotic resistance genes (ARGs) and therefore contribute to human health risk. Effluent discharges from wastewater treatment plants (WWTPs) provide a constant and significant point source of environmental ARGs even in agricultural areas like Iowa. As the first step towards accurate risk assessment of the environmental dissemination of antibiotic resistance, a predictive and quantitative model of ARG persistence in Iowa rivers will be constructed and evaluated. The tasks of the proposed work involve constructing and evaluating a model that accounts for physical, chemical, and biological mechanisms of fate and transport of ARGs. This project is a collaboration with Dr. Chris Rehmann (ISU) and is funded by the National Science Foundation.
Microbiology-influenced corrosion outcomes
Corrosion is a significant challenge for submerged structures that costs the United States nearly half a trillion dollars each year. There is a critical need for knowledge and discoveries enabling better corrosion prevention and control to improve the resiliency of submerged infrastructure while decreasing costs associated with corrosion. Even though the electrochemical mechanism of corrosion is well understood, effective methods for preventing or mitigating corrosion are limited. This is likely because abiotic electrochemistry is only part of the corrosion equation—some of the major yet understudied mechanisms of corrosion are mediated by microorganisms. In fact, microbes have been shown to both inhibit and accelerate corrosion; however, the triggers of these opposing outcomes are largely unknown. Improving our microbiological understanding in corrosion will lead to more sustainable approaches to corrosion management. This project is in collaboration with Drs. Simon Laflamme (ISU) and Roy Sturgill (ISU) and is funded by the Iowa Energy Center and the National Science Foundation.