Pelagic Sargassum in a Gulf Stream Eddy

January 25, 2007


Provided by: James Gower, Fisheries and Oceans Canada
Summary authors & editors: James Gower

Early explorers named the Sargasso Sea (off of southeastern North America) after the Sargassum weed often encountered there. This sea weed was reported to cover large areas, but has never before been observed in satellite images. The image shown above is the first to our knowledge to show Sargassum in the Sargasso Sea. Here water is shown in blue colors and haze and cloud is dark blue and black. Lighter blue, green and yellow indicate increasing concentrations of weed at the sea surface. The floating weed tends to be concentrated into lines by converging flow. On this day a high concentration of the floating weed has been trapped in a Gulf Stream eddy. Other lines of weed can be seen nearby, stretched along the flow of the Gulf Stream. Satellite data (MERIS Reduced Resolution imagery for 4 Oct 2006) are provided by the European Space Agency -- MCI is the Maximum Chlorphyll Index. Our report on the first satellite images of Sargassum weed recorded in the Gulf of Mexico is in press.

Image provided by Jim Gower, Stephanie King and Casey Jones, Institute of Ocean Sciences, Department of Fisheries and Oceans, Sidney, BC Canada.

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