Gulf of Maine Harmful Algal Bloom in Summer 2005 - Part 1: In Situ Observations of Coastal Hydrography and Circulation

An extensive bloom occurred along the coast of the Gulf of Maine in late spring and early summer, 2005. To understand the physical aspects of bloom's initiation and development, in-situ observations from both a gulf-wide ship survey and the coastal observing network were used to characterize coastal circulation and hydrography during that time period. Comparisons between these in-situ observations and their respective long term means revealed anomalous ocean conditions during May 2005: waters were warmer and fresher gulf-wide due to more surface heating and river runoff; coastal currents were at least two times stronger than their climatological means. Surface winds were also anomalous in the form of both episodic burst of northeaster storms and downwelling favorable mean condition. These factors may have favored more vigorous along-shore transport and near shore aggregation of toxic cells (a red tide) in 2005.