For tourists with a taste for clams and mussels, many of New England's seaside eateries are slowly returning to normal after the worst outbreak of toxic marine algae in more than 30 years. The algae made shellfish unfit to eat.
But for scientists, the unusually large bloom raised an important question: Did this event push these tiny organisms farther south than their usual range, making an even larger area of shellfish beds vulnerable to future algae blooms?
Now, with new federal money in hand, researchers here at the Woods Hole Oceanographic Institution (WHOI) are preparing to answer that question - opening a new front in a global scientific assault on so-called "red tides." From Cape Cod, Mass. to Cape Town, South Africa, and coastal regions on at least three other continents, algal blooms are receiving scrutiny as never before. Scientists are expanding research beyond the organisms' basic biology to look for ways to track and forecast their emergence, their effects on the health and livelihoods of coastal residents, and their economic impact, which runs into the tens of millions of dollars in the United States alone.
In the US, researchers are putting the finishing touches on a 10-year research blueprint that places increased emphasis on giving federal, state, and local officials the forecasting and tracking tools needed to protect public health and marine habitats. The blueprint also aims to tease out the subtler effects of the toxins on human health. Armed with new genetic tools, researchers plan to develop sensors to help them identify subtle differences between subgroups of algae within the same species. Shifts in these subgroups - some toxic, some not - could have a profound effect on the level of toxins present during blooms.
The National Oceanic and Atmospheric Administration (NOAA) is not waiting for the blueprint. Earlier this month, it handed a $540,000 check to researchers here at WHOI to help answer whether the algae, known as Alexandrium fundyense, is indeed spreading.
Globally, scientists are gearing up to study blooms that occur where nutrient-rich waters well up from the deep ocean along the Pacific coasts of North and South America and the Atlantic coasts of Africa and Spain. It's part of a long-term program to focus on several categories of coastline and conditions that consistently endure harmful algae blooms. Food in upwelling waters support some of the most productive fisheries in the world. The regions also are subject to harmful algae blooms that threaten those fisheries.
"It's a really exciting time," offers Dennis McGillicuddy, a WHOI scientist who models blooms and the oceanographic conditions that affect them. With new technologies and networks of ocean sensors in the pipeline, "I'm optimistic about what the future holds in being able to understand and predict these blooms with better accuracy."
Ironically, despite widespread recognition that the number of harmful algae-bloom outbreaks is increasing, researchers and public-health officials have no place to go for a national snapshot of the blooms in progress.
This year, blooms have also struck sections of the California and Oregon coasts, as well as Florida's Gulf Coast, according to Ben Sherman, a spokesman for NOAA's Sea Grant program. Texas has experienced a nontoxic bloom.
But nationwide information on outbreaks is largely culled after the fact, notes Donald Anderson, a marine biologist at WHOI who focuses his research on harmful algae blooms. "Current information is gathered through the grapevine," he says.
Although "red tide" has become a generic moniker for algae blooms, the outbreaks can turn seawater into something more akin to Joseph's Amazing Technicolor Dreamcoat. Florida's Gulf Coast and Chesapeake Bay have "mahogany" tides. Blooms off Southeast Asia can tint coastal waters in shades of green or red. Some blooms don't discolor water at all.
Indeed, researchers say, the sheer variety of toxic algae can be daunting. Anyone working in the field is virtually guaranteed to be working on the frontier of research "because there are so many different organisms," says Quay Dortch, coordinator for NOAA's harmful algal blooms program. "Just about the time we think we understand one, something new pops up. That's been part of the frustration."
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