Red tide off the coast of La Jolla, California. Image credit: Wikimedia Commons
As Alexandrium fundyense algae floats and swims in the water, it divides repeatedly, eventually creating the toxic bloom commonly called "red tide." In addition to dividing, however, it also produces dormant cells, or cysts, that drop to the ocean floor.
Researchers from the NOAA-funded Gulf of Maine Toxicity project have observed a larger then usual "seed bed" of these cells lying off the coast of New England—a finding they fear might signal a major bloom this spring and summer.Dennis McGillicuddy, an oceanographer at the Woods Hole Institute, explained that "research has shown that cyst abundance in the fall is an indicator of the magnitude of the bloom in the following year." A recently conducted survey found the highest cyst count ever observed—nearly 60 percent higher than that preceding the historic 2005 bloom.
In addition, the cyst bed has expanded, covering parts of the ocean floor farther south than is typically seen. This means that blooms could reach places like Massachusetts Bay earlier in the season.
In spite of this data, researchers are reluctant to give a forecast of the bloom's severity and impact. McGillicuddy explained:
Even if there is a large bloom offshore, certain wind patterns and ocean currents in the late spring and summer are needed to transport it onshore where it can affect coastal shellfish.
Though the algal blooms present no direct danger to humans, infected clams and mussels concentrate the toxins and can cause paralytic shellfish poisoning in those that eat them. During blooms, areas are quarantined which can be devastating to the local shellfishing industry. During the 2005 outbreak, $20 million was lost in Massachusetts alone.
The team hopes to use the cyst survey data to build a computer model that can better predict algal blooms. Darcie Couture, director of Biotoxin Monitoring for the Maine Department of Marine Resources, explained:
When we get this information about the potential severity of a red tide season, and the dynamics of the bloom once the season has started, it gives us an advantage in staging our resources during an otherwise overwhelming environmental and economic crisis.
Planning and management are essential to minimize the impact these blooms can have on coastal communities.
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