Pfiesteria and Harmful Algal Blooms in the Mid-Atlantic

In The News

A Threat to Our Coastal Waters

Pfiesteria piscicida, a tiny marine organism identified in the last decade in estuaries in North Carolina and Delaware and in the Chesapeake Bay and its tributaries, has been blamed for killing fish and causing health problems in humans. It has been the subject of national press coverage and the cause of considerable confusion and speculation. While questions about its effects and impacts remain, thanks to the diligent work of a number of marine scientists we now know much more about this complicated organism.

Many thousands of species of marine algae form the base of the world's marine food web. Pfiesteria is one of only 80 to 90 of these species – a very small percentage – that produce toxins that can affect human health. Under certain conditions, a dense growth of algae causes "blooms" which color the water red or brown and sometimes produce harmful toxins. Called Harmful Algal Blooms, they can cause serious disease and other chronic impacts on finfish, shellfish and aquatic mammal health.

An unusually problematic algal species – actually an estuarine dinoflagellate – Pfiesteria has brought new attention to harmful algal blooms in the Mid-Atlantic region. It differs from most known toxin-producing algae in that it does not produce a pigment and thus gives no visual evidence of its activity. Among the indicators of potential toxin activity by Pfiesteria species are fish with deep sores and fish kills, though laboratory tests are currently required to confirm their presence.

What Is Pfiesteria?

First named and discovered in North Carolina by researchers JoAnn Burkholder and Ed Noga and characterized with assistance from Karen Steidinger, Pfiesteria's most remarkable attributes are its toxin production and its multiple life stages. According to Burkholder and her research team, Pfiesteria changes from a cyst stage to an amoeboid stage and then to a flagellated stage where it swims actively with a whip-like tail.

Research and field observations suggest that skin contact or inhalation of Pfiesteria toxin can cause health problems. Experiments undertaken in the laboratory have also demonstrated Pfiesteria's toxicity and some researchers have experienced symptoms themselves. During fish kills, round lesions, sometimes the size of a quarter, have become associated with Pfiesteria, though lesions have many other causes as well.

[Pfiesteria]

Algal blooms are hardly new – they have been recorded throughout history. Noticeable nontoxic algal blooms occur regularly in many coastal systems around the world and some feel that their occurrence is on the rise. Although monitoring efforts are now more intensive and may in part account for increased observation, many researchers believe that blooms of some toxic species have been occurring more frequently in coastal waters of certain regions.

Because the toxic Pfiesteria complex of organisms consititutes a relatively new discovery, there is much to be learned about its biology, its impacts on fish and shellfish, on human health, seafood safety and water quality.

Pfiesteria on the Web

The worldwide web offers one of the fastest ways of reaching a wide audience with useful information. The web is especially useful when tracking fast-moving science stores, such as Pfiesteria, where research and results continue to evolve and change. For more information on the subject, visit the links below.

Sea Grant Programs

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"Red Tides" and Harmful Algal Blooms
EcoHab: The Ecology and Oceanography of
Harmful Algal Blooms
U.S. Environmental Protection Agency
National Oceanic and Atmospheric Administration
U.S. Department of Agriculture

Media Sources

Environmental Science & Technology:

	New Pfiesteria toxin identified (January 10, 2007)
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Sea Grant News Center:
     Sea Grant Pfiesteria Briefing (September 19, 1999)
     Sea Grant Pfiesteria Briefing (October 19, 1998)
     Sea Grant Pfiesteria Briefing (September 22, 1998)
     Harmful Algal Blooms

Baltimore Sun:

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The News & Observer, Raleigh, NC

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Washington Post:

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Washington Times:

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