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Remmel '14 Explores Algae Harmful to Fish

February 15, 2012

Vermont Law School's Emily Remmel '14 recently co-authored an article in Ecology Letters about golden algae fish kills.

The article is titled "Toxin-assisted micropredation: experimental evidence shows that contact micropredation rather than exotoxicity is the role of Prymnesium toxins."

Image of fish killThe golden algae is one of a large group of algae known as chrysophytes that are usually found in hot and desert environments and can produce toxins that are lethal to fish and other aquatic life. Under certain environmental stresses, golden algae produce a toxin that negatively affects gill-breathing species such as fish, mollusks, arthropods, and the gill-breathing stage of amphibians. When this occurs fish behave as if there is not enough oxygen in the water. They travel at the top of the water surface or rest on the bottom in edges and shallow areas. Although golden algae can be toxic for fish, they are not a threat to humans.

According to the article's abstract: "Blooms of Prymnesium parvum can severely harm fish and zooplankton, presumably through the release of allelopathic exotoxins that offer advantages for Prymnesium in its interactions with competitors and prey. We show that Prymnesium attaches to zooplankton and fish, causing mortality, whereas exposure of these organisms to Prymnesium across a permeable membrane does not cause mortality.

"We also show that Prymnesium exotoxins are released independently of contact toxicity only in response to experimental procedures or natural causes of stress. Our results are consistent with the idea that toxins have evolved for release during cell-to-cell contact in support of heterotrophy. The evolution of toxin-assisted micropredation would be consistent with mechanisms of natural selection favouring individual fitness as opposed to broadcast allelopathy from which the benefits are more dispersed. Research into the toxicity of Prymnesium and other harmful algal species may profit from focus on processes following physical contact with potential prey."

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