The Geographic Region: The Northeast, U.S. Coast

The geographic region covered by our flora stretches along the coast of the Northeastern United States from Cape Hatteras to Nova Scotia, approximately 35-45 degrees north latitude, and includes estuarine, coastal and continental shelf waters (see map below). This area experiences large seasonal fluctuations in climate, and is also hydrographically complex. The southern part of our range is influenced by the warm waters of the Gulf Stream, whose meanders sometimes break loose as warm core rings (example of satellite image). When Gulf Stream rings impinge upon the continental shelf they decay, and release their tropical diatoms into temperate waters. Transport of cold Scotian Shelf waters south along the Canadian coast introduces boreal taxa into the Gulf of Maine. Thus, one occasionally finds boreal and tropical diatoms, in addition to the mostly temperate flora of this region.

Additionally, there are numerous salt marshes and coastal lagoons throughout this area which support low salinity taxa, and sub-estuaries such as the Pettaquamscutt River Estuary in Rhode Island, which includes a fjord-like region with anoxic bottom waters. It provides habitat for taxa otherwise found in the Baltic, Black, Azov and Caspian Seas.

The resulting diversity of ecological conditions contributes to a high number of diatom taxa found in the Northeast U.S. region.

Map of the Northeast Coast Region