This is one line of evidence that leads Anderson and his colleagues to believe the bloom this spring won't be as extensive as last year's, which closed shellfish beds from the Canadian border to the Cape Cod Canal, and on the outer portions of Cape Cod as well.
"Last year at this time, we issued an advisory for a very large regional bloom that did in fact occur. In hindsight, that advisory was 'easy' because the cyst concentrations were higher than we had ever seen 30 percent higher than in 2004 just before the massive 2005 red tide that many people probably remember," said Anderson. "It's more difficult to make a prediction this year because the numbers of cysts we found are not extreme."
The cysts for this year's bloom have been dormant in the seabed since late last summer, when they were formed at the end of the Alexandrium bloom. With the onset of spring and its warm temperatures and increased light, the cysts are already beginning to germinate, liberating cells that swim to the surface waters. Under the right conditions, a single cell can then divide into several hundred cells within a few weeks. But where and when the resulting bloom will make landfall depends on weather events that cannot be predicted months in advance.
That's where computer modeling can help. While cyst abundance gives a general indication of the magnitude of the bloom, oceanographers Dennis McGillicuddy, a senior scientist in the WHOI Applied Ocean Physics and Engineering department, and his colleague Ruoying He of North Carolina State University (NCSU) have been working with Anderson to simulate the resulting growth and transport of the toxic cells using computer models. Working together over the last decade, the team has developed a computer simulation that incorporates weather conditions, river runoff, and various wind and current patterns to predict the intensity and location of blooms of the toxic algae in the Gul
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Woods Hole Oceanographic Institution