Fighting bloom and gloom

Nor can outbreaks always be tied directly to human activities, Dr. McGillicuddy notes. In Southeast Asia and at the mouth of the Mississippi River, blooms clearly explode as the coastal algae gorge themselves on nutrients from agricultural runoff that originates far inland.

But researchers have noticed that blooms in the Gulf of Mexico often coincide with the arrival of large dust plumes that blow in from Africa. The dust carries iron and other nutrients. In the Gulf of Maine, the breeding ground for this year's mammoth bloom in New England, nutrient sources are largely natural.

Typically, New England's Alexandrium blooms tend to hug the coast from the Bay of Fundy to Massachusetts' Cape Ann, north of Boston, Dr. Anderson says. From there, winds and currents tend to steer the bloom out to sea. This year's Alexandrium bloom was unusual, however. Winds from spring northeasters forced the bloom to hug the coast, driving it into the shellfish grounds of Cape Cod Bay.

From the algae's point of view, one might wonder what all the fuss is about. The toxins they produce probably serve a variety of purposes, notes Raphael Kudela, professor of ocean sciences at the University of California at Santa Cruz. Some toxins may keep predators at bay. Others may actually help the algae extract nutrients from its surroundings.

Yet the toll blooms take can be high. Harmful algae blooms cost the US economy an average of $49 million a year, researchers estimate. Business losses from closed shellfish beds in the Bay State this year are expected to top $24 million. In Alexandrium's case, the toxins concentrate in, but don't kill, shellfish. In other cases, blooms can cut light to sea grasses and other organisms. Sea-grass beds can act as sanctuaries for juvenile fish. Blooms also can reduce oxygen levels. And scientists are concerned about long-term human exposure to bloom toxins that become airborne.

As a result, researchers are starting to field some forecast tools that already are giving them insights into the evolution of blooms and giving them a short-term forecast capability.

For example, last September NOAA unveiled a system to detect and track blooms in the Gulf of Mexico. It combines satellite images of chlorophyll in Gulf waters with data on currents and weather to help officials on Florida's Gulf Coast locate and track blooms.

In the past, it might take NOAA a week to get reports back about outbreaks in the region, notes Rick Stumpf, a researcher with NOAA's Center for Coastal Monitoring and Assessment in Silver Spring, Md. "Now we get the information within a day."

Where blooms are less obvious on the surface, researchers are looking for ways to detect changes that correlate with an emerging bloom. One approach would place optical sensors on moorings to constantly take snapshots of the kinds of algae present and how the mix changes over time. In other cases, detection techniques are decidedly low tech. Researchers have developed a simple "dip stick" test to detect the presence of algae toxin in sea water.

"We've made a lot of progress over the last 10 years," says Dr. Kudela. "Over the next 10 years, with the buildup of ocean observing systems along the coasts, we'll be able to tell what's in the water and follow it. We're starting to shift from being reactive to proactive."

Algae blooms are popping up with increasing frequency around the world, due in part to farm and waste runoff. Among the problem areas:

• Hong Kong is considered to have some of the world's most frequent occurrences of harmful blooms. From 1975 to 2001, they were responsible for 27 fish kills, the government reported.

• America's blooms, often called "red tides," have infested the coasts of southwest Florida for at least a century. The outbreaks have been linked to breathing problems and caused shellfish farms to shut down.

• South Africa has recurring problems with red tides. In 2000, algal blooms reportedly killed 30 million mussels. This March, a red tide prompted the government to warn residents on its west coast not to eat shellfish.

• In 2002, blooms hit the shores of parts of Chile, Ecuador, and Peru, causing authorities to ban fishing in some areas.

Sources: University of Hong Kong; StormCenter Communications; news reports

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