Developing a New Monitoring Tool for Benthic Organisms in the Gulf of Mexico: Loss of Genetic Variability in Meiofaunal Populations

EPA Grant Number: R825355
Title: Developing a New Monitoring Tool for Benthic Organisms in the Gulf of Mexico: Loss of Genetic Variability in Meiofaunal Populations
Investigators: Montagna, Paul A.
Current Investigators: Montagna, Paul A. , Kennicutt, Mahlon C.
Institution: The University of Texas at Austin
Current Institution: The University of Texas at Austin , Texas A & M University
EPA Project Officer: Hahn, Intaek
Project Period: December 1, 1996 through November 30, 1998
Project Amount: $243,469
RFA: Exploratory Research - Environmental Biology (1996) RFA Text |  Recipients Lists
Research Category: Biology/Life Sciences , Ecosystems


A loss of genetic variability in populations of Harpacticoida (Copepoda) has been observed with proximity to offshore hydrocarbon production platforms. The loss of genetic diversity was concordant with increased levels of heavy metal contaminants, but this is confounded with the reef-like nature of a platform. Populations can differentiate when a habitat barrier exists or if there are selection pressures due to habitat influences (e.g., selective fish predation, or different sediment grain size). However, contaminants can act as a selective force. Under strong natural selection, as a population shifts towards a new fitness peak, less-fit phenotypes and their associated genotypes, can disappear, resulting in an overall loss of genetic variability. The purpose of this project is to develop a complete understanding of the cause of genetic variability loss near offshore hydrocarbon platforms. Two experiments will be performed to isolate the confounding contaminant and reef effects. A field experiment will compare population structure at artificial reefs (inactive platforms without contamination), sites where platforms were removed (no reef but contaminants still exist), and operating platforms (reef and contaminant effects). A second experiment will consist of a series of exposure experiments to specific contaminants (e.g., heavy metals, that exist at high levels at production platforms) over three generations to demonstrate that contaminants can cause selection. Levels of sediment contaminants will be measured in both the field and laboratory experiments. Genetic variability in populations will be measured using restriction fragment length polymorphisms of 16S mitochondrial DNA. Mitochondrial DNA is useful in population studies because it has a high divergence rate. It is also maternally inherited, thereby eliminating recombination events. Five species of harpacticoids will be studied, and at least 30 individuals per station will be analyzed to calculate the haplotype diversity index. The results of this study will demonstrate that selection can occur by chronic, sublethal exposure to contaminants associated with offshore production platforms and this can cause populations to lose genetic variability. If selection by contaminants is a general phenomenon, then this would have broad management implications and support the use measuring population structure at the molecular level as an ecological monitoring tool.

Publications and Presentations:

Publications have been submitted on this project: View all 7 publications for this project

Journal Articles:

Journal Articles have been submitted on this project: View all 1 journal articles for this project

Supplemental Keywords:

RFA, Scientific Discipline, Waste, Water, Geographic Area, Ecosystem Protection/Environmental Exposure & Risk, Ecology, Ecosystem/Assessment/Indicators, Ecosystem Protection, Contaminated Sediments, Environmental Chemistry, Genetics, Ecological Effects - Environmental Exposure & Risk, Monitoring/Modeling, Biology, Ecological Indicators, Gulf of Mexico, ecological exposure, monitoring, environmental monitoring, fish kills, benthic organism, contaminated sediment, meiofaunal populations, ecosystem health, hydrocarbons, genotypes, genetic damage, benthic organisms

Relevant Websites: Exit EPA icon

Progress and Final Reports:

  • 1997 Progress Report
  • Final Report