Phytoplankton populations and distribution patterns over the northeastern continental shelf of the United States

Highest cell concentrations for phytoplankton were observed near shore, over Georges Bank, and along the shelf margin. Seasonal periods of abundance occurred during spring and fall, with a pattern of phytoplankton succession noted over the shelf. Dominant species included Skeletonema costatum, Asterionella glacialis, and Leptocylindrus danicus. In addition an unidentified ultraplankton component was widely distributed and abundant over the shelf.