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Intense bloom off coast of Devon and Cornwall, July 2000

At the start of July 2000 very high concentration of chlorophyll were seen from SeaWiFS off the south coast of Devon and Cornwall. This was distinct from a bloom in July 1999 that was highly reflecting and instead was strongly absorbing. Field measurements undertaken on the 25th July on the PML research vessel showed that the bloom was comprised of the 'red tide' dinoflagellate Gyrodinium aureolum . This species absorbs strongly in the blue and green regions of the optical spectrum and hence appears red on the false-colour composites comprising the SeaWiFS bands at 555, 510 and 443nm.

Also found within the bloom was a second plankton species, Noctiluca scintillans, which grazes on the G. aureolum. Noctiluca are visible to the naked eye (~1 mm in diameter), and in calm conditions float near to the surface. By virtue of the high numbers they appear as red patches, or streaks caused by the wind. Noctiluca are bioluminescent; that is, they glow in the dark, which is particularly noticeable if you sail through a patch at night.

You may view articles or hear reports about the bloom by clicking on the images below.

Western Morning News ran an article showing a SeaWiFS image of the bloom, and reported on local environmental concerns related to it. (Saturday 29th July)
The Torquay Herald Express reported the algal bloom, showing a SeaWiFS chlorophyll-band image of the bloom. (Wednesday 2nd August)
The Independent followed up with another SeaWiFS image, and reported on some of the findings of the vessel sent out to investigate. (Friday 4th August)
Radio 4 interviewed Steve Groom on the Today programme. (Saturday 5th August)
Daily Mail took up the story with another SeaWiFS image of the bloom. (Saturday 5th August)
The Evening Herald reported the bloom with comments from Tim Smyth. (Wednesday 9th August)
An article on the bloom appear in the Fall 2000 issue of Backscatter Magazine and the article was also sent out on the Ocean Colour Spectrum e-mail list (November)


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