Hydrographic cruises to provide the seasonal cross-isobath and along-isobath descriptions of the physical, chemical and biological descriptors of the shelf ecosystem of the West Florida shelf to support ECOHAB, 1998-06 to 1999-12 (NCEI Accession 0000539)

Harmful algal blooms of the toxic dinoflagellate, Karenia brevis, have caused massive fish kills in the Gulf of Mexico since the 1500's, with most occurrences on the west coast of Florida. In 1996, the list of states that have experiences natural resource, public health and economic impacts related to this organism expanded, with the addition of Alabama, Mississippi, and Louisiana, to include all the Gulf-coast states and North Carolina. Estimates of economic impacts to Florida and North Carolina from two moderate intensity blooms ranged from 15 to 25 million dollars respectively. The harmful impacts caused by Karenia brevis occur only when cell concentrations increase significantly above low background concentrations that are present year-round in the Eastern Gulf of Mexico. Once a bloom has developed offshore in typically oligotrophic waters, cell concentrations at the 105 level can be maintained for months. During 21 of the past 22 years, red tide blooms have been observed within the region between Tampa Bay and Charlotte Harbor.

The key to understanding any HAB lies in knowing how one algal species has adapted and come to dominate in its particular realm of physical, biological and chemical conditions. Our ability to predict initiation, maintenance, and dispersal of blooms on the Florida shelf has been severely limited by the lack of a quantitative description, or model, of their population dynamics and the physical, biological and chemical regime in which they are embedded. The modeling components of this project will incorporate the quantitative description of blooms and their surrounding environment provided by the field and laboratory portions of this project. The field component will employ a set of monthly hydrographic cruises.