Grantee Research Project Results

2001 Progress Report: Are Genetic Diversity and Genetic Differentiation Bioindicators of Contaminant Impact on Natural Populations? Fundulus heteroclitus as a Model Estuarine Species

EPA Grant Number: R826593
Title: Are Genetic Diversity and Genetic Differentiation Bioindicators of Contaminant Impact on Natural Populations? Fundulus heteroclitus as a Model Estuarine Species
Investigators: Newman, Michael C. , Mulvey, Margaret , Unger, Michael A. , Vogelbein, Wolfgang K.
Institution: College of William and Mary
Current Institution: Virginia Institute of Marine Science , College of William and Mary-VA
EPA Project Officer: Packard, Benjamin H
Project Period: October 1, 1998 through September 30, 2001 (Extended to September 30, 2003)
Project Period Covered by this Report: October 1, 2000 through September 30, 2001
Project Amount: $727,255
RFA: Ecological Indicators (1998) RFA Text | Recipients Lists
Research Category: Aquatic Ecosystems , Ecological Indicators/Assessment/Restoration

Objective:

Molecular genetic traits of the mummichog were evaluated as bioindicators of population-level effects of pollution by testing the following seven hypotheses:

(1) Populations residing in contaminated habitats are genetically distinct from populations in neighboring, clean sites.
(2) Populations at polluted sites exhibit lower than expected genetic variability.
(3) Genetic structure over a landscape reflects the mosaic of polluted and clean habitat.
(4) Populations at contaminated sites display tolerance to local contaminants.
(5) Populations at polluted sites are locally adapted and persistent, and are not replenished by recurrent migration from nearby clean sites.
(6) Tolerant populations exhibit suboptimal performance for fitness-related traits when reared in a clean habitat, indicative of a cost of tolerance.
(7) Performance of individuals and populations is related to genetic variation and lower variation is associated with poor measures of fitness.

Progress Summary:

All research milestones were met; however, experiments associated with Hypotheses 6 and 7 are being repeated after redesign to enhance statistical power. Results of the expanded field survey (see Figure 1), and all experiments have been analyzed. Formal analyses resulted in acceptance of Hypotheses 1, 3 (conditionally), and 5, and rejection of Hypothesis 2. Hypothesis 1 was supported by distinct genetic characteristics of fish from the highly contaminated AW site. There was no support for Hypothesis 2 from allozyme or mtDNA data. Hypothesis 3 was true only in the context that the AW site was distinct from the other sites; but there was no statistically significant relationship between contamination level and genetic qualities of fish at the surveyed sites. Hypothesis 4 was strongly supported by statistical testing of differences in embryonic development and juvenile growth for inter-estuarine (Elizabeth River versus York River) populations, and weakly supported for intra-estuarine (Elizabeth River sites) populations. Embryos produced from adults from the AW site, but reared for their entire lives in clean mesocosms, retained their high tolerance of the teratogenic effects of PAH-contaminated sediments. In strong contrast, embryos produced from fish from the relatively clean York River (CI) were much more sensitive, and fish from other Elizabeth River sites (RS, JC, and CM) were intermediate in their sensitivity. The distinct genetic qualities and tolerance of AW fish, despite high effective migration rates (10 to 18 migrants per generation) among sites, supports Hypothesis 5: the AW population remains genetically distinct despite high rates of migration. It was clear that genetic differentiation, but not genetic diversity, reflects a population effect at the AW site.

Figure 1. The original (Panel B, nine South Branch sites), and new (four York River sites and four Eastern Branch Elizabeth River sites) sites from which mummichog genetic data were collected.

Figure 1. The original (Panel B, nine South Branch sites), and new (four York River sites and four Eastern Branch Elizabeth River sites) sites from which mummichog genetic data were collected.

Future Activities:

A no-cost extension was granted to allow refinement and repetition of experiments associated with Hypotheses 6 and 7.

Journal Articles:

No journal articles submitted with this report: View all 13 publications for this project

Supplemental Keywords:

water, watersheds, sediments, estuary, ecological effects, carcinogen, genetic, PAHs, indicators, Chesapeake Bay., RFA, Health, Ecosystem Protection/Environmental Exposure & Risk, Geographic Area, Ecological Indicators, Risk Assessments, Ecosystem Protection, Chesapeake Bay, Ecosystem/Assessment/Indicators, exploratory research environmental biology, Ecological Effects - Environmental Exposure & Risk, EMAP, fundulus heteroclitus, bioindicator, human exposure, risk assessment, ecosystem indicators, genetic variability, monitoring, contaminant impact, estuarine ecosystems, aquatic ecosystems, genetic diversity

Progress and Final Reports:

Original Abstract

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.