Are Genetic Diversity and Genetic Differentiation Bioindicators of Contaminant Impact on Natural Populations? Fundulus heteroclitus as a Model Estuarine SpeciesEPA 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: Virginia Institute of Marine Science
Current Institution: Virginia Institute of Marine Science , College of William and Mary-VA
EPA Project Officer: Hahn, Intaek
Project Period: October 1, 1998 through September 30, 2001 (Extended to September 30, 2003)
Project Amount: $727,255
RFA: Ecological Indicators (1998) RFA Text | Recipients Lists
Research Category: Ecosystems , Ecological Indicators/Assessment/Restoration
Molecular genetic traits of the mummichog, Fundulus heteroclitus, will be evaluated as bioindicators of population-level effects of pollution by testing 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 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.
Improvement to Risk Assessment: Although population viability is often an implied endpoint in ecological risk assessments, directly relevant information is difficult to obtain. Consequently, risk assessments rely heavily on effects to individuals and extrapolate from these to imply consequences to populations. Application of molecular bioindicators for population effects will be demonstrated across a landscape feature, the Elizabeth River. Such bioindicators will be valuable to document contaminant impact before and to monitor recovery after remediation.
To test hypotheses 1-3 and 5, surveys will be conducted at clean and polluted sites. To test hypotheses 4 and 6, fish will be obtained from clean and polluted sites, and reciprocally reared in clean and polluted mesocosms. Embryo, juvenile, and adult performance will be measured. Endpoints will include terata, growth, fecundity, age at maturity, lesions, condition index, and mortality. Hypothesis 7 will be tested by challenging populations representing clean and polluted sites with a highly pathogenic biovar of Vibrio anguillarum. Allozyme and DNA diversity will be determined in the above studies.
This study will provide environmental managers with a better understanding of how chronic exposure of natural populations to contaminants can alter genetic variability, population structure, and toxicant tolerance in local populations, and how they relate to organism health. The potential use of allozyme and DNA genetic diversity as a biomarker of population impact of pollution will be demonstrated.