. | . |
Toxic 'marine snow' can sink quickly, persist at ocean depths by Staff Writers Raleigh NC (SPX) Nov 29, 2016
In a new study, researchers from North Carolina State University found that a specific neurotoxin can persist and accumulate in "marine snow" formed by the algae Pseudo-nitzschia, and that this marine snow can reach significant depths quickly. These findings have implications for food safety policies in areas affected by toxic marine algal blooms. When algae cells run out of nutrients and start to die, they clump together and sink as marine snow. The algae and its marine snow aggregates can serve as a major food source for other forms of marine life like plankton-eating fish and shellfish. Pseudo-nitzschia is a microscopic algae that occurs naturally in coastal waters, and is of particular concern due to its production of the neurotoxin domoic acid. When domoic acid-containing Pseudo-nitzschia enter the food chain, humans can accidentally consume it via shellfish. This type of shellfish poisoning, known as amnesic shellfish poisoning, can cause neurological and gastrointestinal symptoms ranging from short-term memory loss to - in rare cases - death. Astrid Schnetzer, associate professor of marine, earth and atmospheric sciences at NC State, wanted to know how domoic acid gets transported to depth via marine snow after a toxic algal bloom and how long it may persist. In a previous study she showed that marine snow can reach depths of several hundred meters within a few days, which contradicted previous theories suggesting that it might dissipate and dissolve long before reaching the ocean floor. "Recent large toxic blooms off of the California coast and the attendant damage to local shellfish and the shellfish economy underscore the importance of understanding how long the marine snow remains toxic, how deep it can go and how long marine organisms are exposed to the toxin," Schnetzer says. "The fact that high levels of domoic acid can be found in marine life months after a bloom demonstrate the need for deciphering the mechanisms by which domoic acid reaches the seafloor." Schnetzer and colleagues created their own toxic algal bloom in the lab using P. australis algae, one of the most toxic Pseudo-nitzschia species and one that blooms along the U.S. West Coast. They found that after two weeks, toxic marine snow from this algae could sink at rates of over 100 meters per day. Domoic acid did not dissipate appreciably during the sinking period, retaining up to 80 percent of its original toxicity. "This study confirms that marine snow is a major vector in terms of getting domoic acid to depth," Schnetzer says. "Our future work will focus on the ways in which smaller organisms that feed on marine snow may be affected by the toxicity, and how that in turn can affect the larger food web." The research appears in Harmful Algae. The work was funded by National Science Foundation grants 1459406 and 0850425 and North Carolina Sea Grant NA10OAR1040080. Schnetzer is corresponding author. NC State's Christopher Osburn, NC State and University of North Carolina at Chapel Hill's Robert Lampe, UNC-Chapel Hill's Adrian Marchetti, University of South Carolina's Claudia Benitez-Nelson and University of Southern California Los Angeles' Avery Tatters contributed to the work. Research paper: "Marine snow formation by the toxin-producing diatom, Pseudo-nitzschia australis"
Related Links North Carolina State University Water News - Science, Technology and Politics
|
|
The content herein, unless otherwise known to be public domain, are Copyright 1995-2024 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. General Data Protection Regulation (GDPR) Statement Our advertisers use various cookies and the like to deliver the best ad banner available at one time. All network advertising suppliers have GDPR policies (Legitimate Interest) that conform with EU regulations for data collection. By using our websites you consent to cookie based advertising. If you do not agree with this then you must stop using the websites from May 25, 2018. Privacy Statement. Additional information can be found here at About Us. |