Foraminifera are everywhere. In addition to being some of the dominant organisms in the oceans, forams are also found in brackish water environments like lagoons and estuaries, as well as absolutely freshwater environments. These low-salinity forams don't make the dramatic tests that the marine ones do, so it's been hard to differentiate between them until recently.

Our laboratory sits on the west bank of the Hudson River, in New York State. We are at the upper end of a long estuary that extends about 160 miles south, to New York City. This estuary, as well as being very beautiful, is home to a wide variety of different organisms, and the populations change as the salinity increases downriver.

Two researchers, McCrone and Schafer, did a traditional survey of the Hudson River for foraminifera in the late 1960's, finding them as far north as Haverstraw (at the top of the Tappan Zee). However, we think that many types may have been missed, because the method they used relies on the cells' ability to make tests. Many forams don't make tests at all, and other won't make them under some conditions. We have been searching for foraminifera throughout the estuary, using DNA signatures to identify the forams instead of test shape.

Of course, there's no way we could do this work alone. The crew and student volunteers aboard the Half Moon, a replica of the first European ship to explore the Hudson River estuary, have enthusiastically embraced our research project. Check out their Website for their stories and photos of Playing in Mud for Science. Hannah Giles, a now-college freshman, went hunting for forams in a pond near her home as a high-school student. Our work on freswater forams, in collaboration with the Pawlowski lab at the University of Geneva, was published in 2003 (Holzmann, M., Habura, A., Giles, H., Bowser, SS., and Pawlowski, J. Freshwater foraminiferans revealed by analysis of environmental DNA samples. Journal of Eukaryotic Microbiology 50(2):135-139), and work is continuing.