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, June 1998 - December 1999 (NODC 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.
Purpose:
1. Model the initiation, maintenance, and export of K.
brevis red tides on the west Florida shelf at different time
and space scales to predict landfall 2. Describe the
physical habitat that effects transport and concentration of
K. brevis 3. Determine the sources of inorganic and organic
nutrients that allow growth and persistence of large K.
brevis populations in coastal waters.