Sediment Contaminant Effects on Genetic Diversity: New Approach using DNA Analyses of MeiobenthosEPA Grant Number: R825439
Title: Sediment Contaminant Effects on Genetic Diversity: New Approach using DNA Analyses of Meiobenthos
Investigators: Coull, Bruce C. , Chandler, G. Thomas , Quattro, Joseph M.
Institution: University of South Carolina at Columbia
EPA Project Officer: Hahn, Intaek
Project Period: February 24, 1997 through February 23, 2000 (Extended to February 23, 2001)
Project Amount: $372,642
RFA: Exploratory Research - Environmental Biology (1996) RFA Text | Recipients Lists
Research Category: Ecosystems , Biology/Life Sciences
Our main goal in this study is to develop a population-genetics level sediment bioassay that will be more sensitive and more relevant to long-term benthic community protection than current EPA acute, chronic and sub-chronic toxicity tests. Chronic toxicant loads in sediments may drive populations toward a limited set of tolerant genotypes over time. Such genomic losses reduce a species plasticity to adapt to the new stresses that inevitably arise as human population pressures on aquatic ecosystems increase. With modern molecular biology techniques (PCR, gene sequencing), genomic changes directly attributable to toxicants can be easily measured in individual eukaryotic organisms of small size. If the organisms are culturable over multiple generations and have rapid life cycles toxicant effects over several meiofauna are just such organisms.
By comparing field-collected meiofauna inhabiting clean sediments or contaminated sediments at a Charleston (SC) Harbor EPA superfund site, we propose to determine if a history of chronically-elevated contaminant loads results in reduced (or enhanced) genetic diversity of meiobenthos. We will directly assess toxicant effects on meiobenthos genetic diversity in the field, and in lab culture, using the molecular techniques of polymerase chain reaction (PCR) and gene sequencing. These techniques will be used in a seasonal field study over two full years with the most abundant meiobenthic copepod in this ecosystem to assess natural and toxicant-influenced temporal changes in population genetic structure. A comparative laboratory study will be conducted to assess if genetically similar meiofauna stock populations from uncontaminated watersheds undergo changes in genetic diversity when cultured over multiple generations in contaminated versus clean sediments. For the first time, direct correlations will be possible between field-effects toxicant/genetic assessments and controlled laboratory culturing/genetic studies using meiofaunal populations of knowing genetic diversity, and sediments containing known toxicants loadings.