Strayer, D. L. Institute of Ecosystem Studies, strayerd@ecostudies.org
Caraco, N. L. Institute of Ecosystem Studies, caracon@ecostudies.org
Cole, J. J. Institute of Ecosystem Studies, colej@ecostudies.org
Findlay, S. Institute of Ecosystem Studies, stfindlay@aol.com
Pace, M. L. Institute of Ecosystem Studies, pacem@ecostudies.org

 
EFFECTS OF ECOSYSTEM STRUCTURE ON IMPACTS AND ECOLOGY OF THE ZEBRA MUSSEL IN THE HUDSON RIVER ESTUARY
 
The influence of a species on ecological processes depends on the physical and ecological structure of the ecosystem as well as the abundance and ecological characteristics of the species. We illustrate this proposition with our data on the effects of the zebra mussel invasion on the Hudson River ecosystem. Zebra mussels appeared in the Hudson in 1991, and soon constituted over half of heterotrophic biomass in the freshwater part of the estuary. Consequently, biomass of phytoplankton and small zooplankton fell to 10-15% of pre-invasion values. Large zooplankton did not decline severely, and bacterioplankton actually increased. Native bivalves declined by 65-85%, but the qualitative response of other zoobenthos varied with water depth. Concentrations of some dissolved gases and nutrients changed as well. We believe that the Hudson responded as it did because it is well mixed, contains much suspended silt and dissolved nutrients, includes extensive areas of shallow water, and has large inputs of organic matter from its watershed. We predict that ecosystems that differ in these key attributes will respond differently to benthic grazers. Similarly, the spatial extent and temporal dynamics of the zebra mussel population itself reflect the physical and ecological characteristics of the Hudson.
 
Day: Wednesday, Feb. 3
Time: 03:30 - 03:45pm
Location: Eldorado Hotel
 
Code: SS18WE0330E