San Diego, Calif. Each year, phytoplankton blooms known as "red tides" kill millions of fish and other marine organisms and blanket vast areas of coastal water around the world. Though the precise causes of red tides remain a mystery, a team of researchers in the United States and Spain has solved one of the main riddles about these ecological disasters by uncovering the specific mechanism that triggers phytoplankton to release their powerful toxins into the environment.
"Previous theories about how phytoplankton release toxins proposed a rather awkward, untested 'exudation' mechanism," said researcher Pedro Verdugo of the University of Washington in Friday Harbor. "The true mechanism has been a very exciting riddle to crack and it provides a handle on understanding the development of huge phytoplankton blooms, eventually affecting several square miles of the ocean's upper surface."
Verdugo and his colleagues, Kellie L. Vigna also of the University of Washington and Ivan Quesada of the Universidad Miguel Hernandez in Alicante, Spain, will present their research at the 56th Annual Meeting of the Biophysical Society (BPS), held Feb. 25-29 in San Diego, Calif.
Red tides appear when naturally occurring algae including Karenia brevis multiply very rapidly, becoming so concentrated that the ocean surface takes on a reddish hue. Karenia produces brevetoxin, a powerful neurotoxin that binds to nerve and muscle cells, leading to substantial marine life mortality and human morbidity. The blooms are triggered by some as yet unknown fluctuations in ocean temperature, salinity, and available nutrients.
The researchers discovered that Karenia and other unicellular microalgae function very much like the secretory cells we have in our bodies. Namely, they store inside membrane-lined microscopic vesicles their active chemicals such as hormones, antibacterial products, and, in Karenia's case, toxins. When prope
|Contact: Ellen R. Weiss|
American Institute of Physics