Detection of Karenia brevis in an early bloom stage using the BreveBuster Gary Kirkpatrick 1, David Millie 2, Cindy Heil 3, Mark Moline 4, Steven Lohrenz 5, Richard Stumpf 6 and Oscar Schofield 7 1 Mote Marine Laboratory, Sarasota, FL 34236, USA; 2 Florida Institute of Oceanography, St Petersburg, FL 33701, USA; 3 Florida Fish and Wildlife Research Institute, St Petersburg, FL 33701, USA; 4 California Polytechnic State University, San Luis Obispo, CA 93407, USA; 5 University of Southern Mississippi, Stennis Space Center, MS 39529, USA; 6 NOAA/NOS, Silver Springs, MD 20910, USA; 7 Rutgers University, New Brunswick, NJ 08901, USA On October 20, 2004, during a monthly HAB survey of the southwest coast of Florida, a shipboard BreveBuster signaled the presence of Karenia sp at a single location just offshore of Naples, Florida. Microscopic examination of a water sample collected near the surface by Niskin bottle confirmed the presence of a medium level of Karenia brevis (Figure 1). A time series of NOAA HAB Bulletins documented the subsequent development of a bloom patch adjacent to the BreveBuster detection site over the following two weeks. This bloom patch was revisited during a MERHAB cruise three weeks after the first encounter as the patch moved southward toward the Florida Keys. During that cruise the BreveBuster, while running comparison studies with the sandwich hybridization molecular probe detection technology, was able to map the near-surface distribution of the bloom. Good comparisons were found between the BreveBuster-generated bloom distributions and those depicted in the NOAA HAB Bulletins for the time period of the cruise. That bloom continued to drift southward until it reached the Keys in late December Figure 1. Florida red tide survey cruise track from October , 2004 depicting the Karenia sp Similarity Indexes determined by a shipboard BreveBuster. Red arrow points to the site where the BreveBuster reported the presence of Karenia sp and the confirming microscope cell count. Abstract Acknowledgements This work was supported by the Florida Fish and Wildlife Conservation Commission/FWRI Grant No , the National Oceanic and Atmospheric Administration/MERHAB Grant No. NA16OP2787 and the National Science Foundation/DBI Grant No The authors wish to thank the numerous ship’s crews and science crews who contributed to this effort. MethodDiscussion Results Prototype shipboard Optical-based Phytoplankton Discriminator (OPD) (left). Miniaturized, reconfigured OPD payload for in-water deployment (right). Both instruments were operated on deck to acquire Karenia sp. Similarity Indexes. A time sequence of NOAA HAB Bulletins showing the distribution of Karenia brevis microscope cell counts and BreveBuster Similarity Indexes. In October the bloom was very spatially limited off the coast of Naples, Florida. Note the southerly movement and further development of the bloom in early November. It continued to move south and out of the survey region later in November. By the late December the bloom impacted the Florida Keys. The figure above shows the position of the initial bloom detection site just west of Naples, Florida relative to the high colored dissolved organic material (CDOM) water coming from the Caloosahatchee River just north of Fort Myers. It is hypothesized that the interface between the river-impacted water and the more oceanic water to the south is a location where Karenia brevis could concentrate. This figure illustrates a very strong silica gradient in the area where the bloom was first detected just west of Naples, Florida. The drop in silica concentration could limit the growth of normally abundant diatoms in this area and thus provide a competitive advantage to Karenia brevis. October 19-21, 2004 November 8-11, 2004 November 16-18, 2004