Grantee Research Project Results

Hypoxia and Macoma balthica: Ecological effects on a key infaunal benthic species

EPA Grant Number: F5E61380
Title: Hypoxia and Macoma balthica: Ecological effects on a key infaunal benthic species
Investigators: Long, William C.
Institution: College of William and Mary-VA
EPA Project Officer: Hahn, Intaek
Project Period: September 1, 2005 through August 1, 2008
Project Amount: $106,692
RFA: GRO Fellowships for Graduate Environmental Study (2005) RFA Text | Recipients Lists
Research Category: Academic Fellowships

Objective:

I am examining the effects of hypoxia (i.e., low dissolved oxygen) on community and population dynamics in the Chesapeake Bay. I am focusing on a dominant bivalve, Macoma balthica, which provides an important food-web link between its food sources, detritus and phytoplankton, and its predators, commercially important species such as the blue crab, Callinectes sapidus. I will be examining the effects of hypoxia upon the growth, reproduction, mortality, and predation of M. balthica.

Determine the effects of hypoxia on mortality in M. balthica.
Determine the effects of hypoxia on reproduction in M. balthica.
Determine the effects of hypoxia on the growth of M. balthica.
Determine the effect of hypoxia on predation on M. balthica.
Use these observations to create a mathematical model of the system to show the effects of hypoxia on both the population dynamics of M. balthica and the trophic transfer to fish and crustaceans.

Approach:

I will be using four main methods to complete these objectives. First, a field survey in the York and Rappahannock Rivers will provide large-scale representation of M. balthica population density both within and outside of hypoxic areas, along with information about growth and reproduction. Second, I will use laboratory experiments exposing live M. balthica to various tightly controlled dissolved oxygen levels to measure growth, reproduction, and mortality of M. balthica under a range of dissolved oxygen conditions. Third, I will conduct field experiments with caged and un-caged transplanted clams to measure predation-induced mortality inside and outside of hypoxic areas. Finally, to measure fecundity in M. balthica, I am developing an enzyme-linked immunosorbent assay (ELISA) using monoclonal antibodies specific to egg proteins. After quantifying the average amount of protein in each egg I will be able to use this assay to determine the number of eggs in a given female. The information from the various experiments will be used to create a mathematical model that will predict the effect of various hypoxic regimes on M. balthica populations, and its effect on trophic transfer up the food web.

Supplemental Keywords:

Hypoxia, Low Dissolved Oxygen, Baltic clam, Macoma balthica, Eutrophication, Predator-prey, Chesapeake Bay, York River, Rappahannock River, Benthos, Infauna, ELISA, Fecundity, Population Dynamics, Mathematical Model,, Scientific Discipline, Ecosystem Protection/Environmental Exposure & Risk, Habitat, Environmental Monitoring, Ecology and Ecosystems, Ecological Risk Assessment, habitat dynamics, Blue Crab Callinectes Sapidus, environmental sources of mortality, food web, community composition, habitat disturbance, hypoxia, phytoplankton, conservation biology, environmental stress, water quality, mortality

Progress and Final Reports:

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.