Grantee Research Project Results

The Impacts of Endocrine Disrupting Pollutants on Copepod-Vibrio Interactions in Estuarine Environments

EPA Grant Number: FP917089
Title: The Impacts of Endocrine Disrupting Pollutants on Copepod-Vibrio Interactions in Estuarine Environments
Investigators: Aruda, Amalia Marie
Institution: Woods Hole Oceanographic Institution
EPA Project Officer: Packard, Benjamin H
Project Period: September 1, 2010 through August 31, 2013
Project Amount: $111,000
RFA: STAR Graduate Fellowships (2010) RFA Text |  Recipients Lists
Research Category: Academic Fellowships , Fellowship - Water Quality: Coastal and Estuarine Processes

Objective:

Estuaries are highly dynamic and productive ecosystems that often are exposed to high levels of endocrine disrupting pollutants and other contaminants. Copepods are a major food source in estuarine ecosystems and are beneficial hosts for the abundant bacteria Vibrionaceae, which include human and animal pathogens. This project will investigate how microbial associations affect copepod physiology, whether copepods regulate these microbial associations, and subsequently how exposure to endocrine disruptors may affect copepod-Vibrio interactions.

Synopsis:

Estuaries can be major sinks for terrestrial and waterborne contaminants thereby exposing organisms such as copepods to high levels of pollutants. Copepods are abundant crustaceans that enhance survival of the bacteria Vibrionaceae, which include human and animal pathogens. This project examines how Vibrio attachment affects copepods, whether copepods can control what microbes attach to them, and how exposure to endocrine disrupting pollutants may alter the copepod response to Vibrio attachment.

Approach:

The first set of laboratory experiments will examine how an estuarine copepod, Apocyclops spartinus, responds to colonization by different classes of Vibrio sp. (e.g. facultatively symbiotic, commensal) by comparing copepod physiology and gene expression between treatments. These copepod responses to Vibrio attachment will then be explored in the context of stressors such as endocrine disrupting compounds (EDCs). Copepods and Vibrio strains will be separately exposed to two ecologically relevant EDCs (methoprene, Bisphenol A [BPA]) and their growth and development will be monitored to determine the effects of EDCs when the species are isolated from one another. Copepods colonized by the different classes of Vibrio then will be exposed to EDCs and copepod gene expression and physiology will be compared to those treatments without exposure to EDCs. These treatments will assess how EDCs may alter the copepod-Vibrio association.

Expected Results:

Differential gene expression, potentially in immune response (e.g., production of antimicrobial peptides) and/or the endocrine system (e.g., shedding of associated microbes by molting) in copepods exposed to different “types” of Vibrio strains would suggest that A. spartinus can distinguish between beneficial and commensal associations with Vibrio and is perhaps regulating its microbial associations. Copepod host responses to microbial associations could be an important influence on Vibrio ecology that has, to our knowledge, not yet been explored. Exposure to endocrine disrupting pollutants (as are often present in contaminated estuaries) may disturb copepod-Vibrio interactions. Our approach will reveal if changes in host-microbe interactions are driven primarily by EDC effects on individual members of the association and if the impacts of EDCs are further compounded (either antagonistically or synergistically) when the organisms interact. Differences in gene expression patterns in copepods colonized by Vibrio sp. under normal conditions versus EDC exposed conditions could further indicate that copepod regulation of colonization by various Vibrio “types” may be context dependent. Alteration of interactions between copepods and microbes due to stresses may impact both Vibrio ecology and copepod populations.

Potential to Further Environmental/Human Health Protection:

The results of this study will influence the understanding of how environmental stressors such as widespread endocrine disrupting pollutants (methoprene, BPA) can affect the copepod host response to Vibrio sp. and alter the nature of copepod-Vibrio interactions. The broader impacts of this study will help model how degraded water quality in estuaries due to endocrine disrupting pollutants can modulate copepod-Vibrio interactions to affect the life history of copepods and the survival of Vibrionaceae, which include human and animal pathogens. Through potentially changing the dynamic of the copepod-Vibrio interaction, EDCs may expose copepods to novel stress through making copepod hosts less able to regulate their normal balance with microbial flora.

Supplemental Keywords:

Vibrio, Apocyclops spartinus, host response, gene expression, endocrine disruptors, bisphenol A, methoprene, microbial interactions, estuary,, RFA, Health, PHYSICAL ASPECTS, Scientific Discipline, POLLUTANTS/TOXICS, HUMAN HEALTH, Exposure, Health Risk Assessment, Chemicals, Endocrine Disruptors - Environmental Exposure & Risk, Epidemiology, Risk Assessments, endocrine disruptors, Physical Processes, Biochemistry, Molecular Biology/Genetics, Endocrine Disruptors - Human Health, chemical exposure, pesticide exposure, fish, endocrine disrupting chemicals, altered sexual development, bioavailability, exposure studies, hormone degradation, fish consumption, human exposure, human growth and development, groundwater contamination, thyroid, reproductive processes, thyroid function, dietary exposure, agrochemicals, biochemical research, human health risk

Progress and Final Reports:

2011

2012

Final