Microbial Ecology of the Hudson-Raritan Estuary

The Lower Hudson and East Rivers, both within walking distance of Haskins Labs, are complex aquatic habitats where waters from Long Island Sound, the Atlantic Ocean and Upper Harbor, and the upriver freshwater reaches of the Hudson all mix. Contrary to popular conception, these waters contain numerous fish and shellfish, but these large organisms are just part of a complex food web that includes many smaller planktonic species: the zooplankton (small planktonic animals), phytoplankton (single-celled plant-like organisms) and other microorganisms. Over the last decade and a half I’ve been monitoring the phytoplankton component of this foodweb by weekly sampling, using classical methods and identifying the dominant taxa from living material with the light microscope.

These data have been analyzed mathematically using two multivariate approaches, correspondence analysis and nonlinear multivariate polynomial regression (MPR) analysis. The MPR analysis is in collaboration with Dr. David Vaccari of Stevens Institute, New Jersey. Two manuscripts have been submitted for publication. These reveal the dominant physicochemical factors associated with various assemblages of species. In the Hudson, typically highly stratified, with layers of different salinity and hence density, the samples from an 8-year period are separated by the correspondence analysis into relatively distinct, non-overlapping clusters, corresponding to 4 temperature ranges and 3 salinity ranges. In the East River, where typically the incoming waters are mixed by highly turbulent currents, the samples don’t separate out into distinct clusters. We characterized the various species or other taxa with regard to probability of occurrence at various temperatures and salinities.

Recently I've begun to add a molecular dimension to this work, extracting DNA from plankton samples and amplifying the 18sRNA gene by PCR to study species composition of samples, working in the lab of Dr. Rob DeSalle at the American Museum of Natural History.

Other studies of local estuarine microorganisms have involved soil amoebas in sediments from a highly oil-impacted salt marsh in Staten Island. (Anderson et al 2001), and in sediments in the Hackensack Meadowlands.