February 2005, WASHINGTON, D.C. – Researchers have discovered that marine seaweeds
have a remarkable and previously unknown capacity to detoxify serious
organic pollutants such as TNT or polycyclic aromatic hydrocarbons, and
they may therefore be able to play an important role in protecting the
ecological health of marine life.
The studies, conducted by
scientists from the College of Engineering at Oregon State University
and the Marine Science Center at Northeastern University, were
presented today at the annual meeting of the American Association for
the Advancement of Science.
The findings may have important implications for seafood safety, since
some of the marine organisms most at risk from these toxins are marine
invertebrates such as clams, shrimp, oysters or crab that tend to
"bioaccumulate" them. One possibility, the researchers say, might be to
plant appropriate seaweeds as a protective buffer around areas being
used in aquaculture.
"We found that certain red seaweeds had an intrinsic ability to
detoxify TNT that was 5-10 times faster than any known terrestrial
plant," said Greg Rorrer, a professor of chemical engineering at OSU.
"Marine seaweeds have a more efficient uptake mechanism than even
terrestrial aquatic plants to at least neutralize organic pollutants."
The researchers call this process "phycoremediation," derived from phykos, a Greek word for seaweed.
The studies, which are supported by the Office of Naval Research and
the Oregon Sea Grant Program, are of particular interest in the case of
trinitrotoluene, or TNT, because of unexploded bombs or military shells
found in some places around the world’s oceans. There is a general
concern these shells could potentially corrode.
"It’s important to know how corals, fisheries and plant life might
respond to exposure to TNT or other toxins," Rorrer said. The study is
looking at not just TNT, which is commonly found in munitions, but at
polycyclic aromatic hydrocarbons, such as naphthalene, benzopyrene and
other PAHs that are sometimes associated with the use of motorcraft or
Ongoing studies found that marine seaweeds processed toxins to a much
less harmful form, and in a way that did not appear to harm the
seaweed. The biochemistry involved, they say, is similar to that found
in many land organisms, but more powerful and effective. Until now, the
capability of marine seaweeds to deal with these toxins had never
before been demonstrated.
It’s unclear yet whether similar plants can be identified, the
researchers said, that will perform this function in terrestrial fresh
waters, such as streams or lakes.
These research outcomes should lead to the development of new
bioremediation technologies that use seaweed in engineered systems to
remove organic contaminants from the marine environment, the scientists
Studies to create genetically engineered seaweeds that perform these
functions even better are also promising, the researchers said.
Source : Oregon State University