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Beautiful, but dangerous

Invader organisms threaten marine life

Researchers worked along the Boston waterfront at Rowes Wharf checking out different organisms as part of a research project along the Atlantic coast. The colorful invaders, attached to a hose, (inset) are proving to be a threat to marine life in the Atlantic Ocean.
Researchers worked along the Boston waterfront at Rowes Wharf checking out different organisms as part of a research project along the Atlantic coast. The colorful invaders, attached to a hose, (inset) are proving to be a threat to marine life in the Atlantic Ocean. (Globe Staff Photo / David L. Ryan)

Researchers lay flat on their stomachs on floating docks at Boston's Rowes Wharf yesterday and scraped off clumps of the organisms with spatulas and their hands.

They were hunting for invaders that could destroy native plants and marine life in the Atlantic Ocean.

Art Mathieson, a seaweed specialist from the University of New Hampshire, held up a 3-foot-long strand of native seaweed as if he had caught a trophy-winning bass. The strand was beautiful, with brilliant shades of orange and red, but the bright colors were a bad sign, a symptom of invasion.

Mathieson is among a group of roughly 20 researchers sampling the Atlantic Coast from Woods Hole to Maine as part of a national effort to annually track the growth of invasive species. The number of nonnative species in US oceans has increased during the past two centuries and the rate is not tapering, and the effects are costing the US economy about $137 billion a year, according to the US Commission on Ocean Policy.

The researchers in Boston yesterday are a part of the MIT-run Sea Grant program, sponsored by the National Oceanic & Atmospheric Administration. The group just finished three days of sampling in Massachusetts as part of their weeklong survey along New England's shores. The study is the third one of its kind in the last decade.

"As the world get smaller, as it gets easier to get from place to place, it gets easier for invasive species to go from place to place because they tag along," said Dorn Carlson, research director for NOAA's national Sea Grant program. "Once an invasive species comes and it is actually threatening a native species you care about, you can't just ignore it."

The researchers made an alarming find this week on Cape Cod and in Boston Harbor, a form of red seaweed that has never been detected this far north. Scientists have found it previously in Narragansett Bay in Rhode Island.

The scientists said the leafy algae, probably from Japan, is known to take over the habitat of native organisms, but it is too early to tell whether it is causing damage in New England. The red seaweed can replace other algae that snails and other invertebrates rely on for food during the winter, they said.

James Carlton, professor of Marine Science at Williams College, said researchers usually find one or two new invasive species each time they have done the study. "Sometimes we show someone something new and it's the size of a microdot, and they say, why is that important?" he said. "It's really in the abundance."

The scientists said they are most concerned with an aggressive genus like Didemnum, a group of sea squirts that cover the sea floor like a mat and often replace the organisms that fish and shellfish eat. The sea squirts also carry an economic price for regions like New England where fishing is a robust industry. Didemnum was found on Cape Cod this week but not in Boston yesterday.

The scientists are taking an inventory so the state can have a solid idea of its native and nonnative species along the coast line, Carlton said.

The exploding population of zebra mussels in fresh water in recent years is the most notorious example of the effects of invasive species. They have clogged intake pipes for drinking water plants and pushed out native organisms, said Harlan Cohen, an adviser to the World Conservation Union on ocean governance and international institutions.

Cohen said some people do not recognize that some organisms that might be harmless in their native environments can have grave effects elsewhere.

"Most people do appreciate landscapes as they know them," Cohen said, "so people may not be happy when they realize what they've changed was the traditional view of the harbor."

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