Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Iron stimulates blooms of toxin-producing algae in open ocean

09.11.2010
A team of marine scientists has found that toxin-producing algae once thought to be limited to coastal waters are also common in the open ocean, where the addition of iron from natural or artificial sources can stimulate rapid growth of the harmful algae.

The new findings, reported this week in the Proceedings of the National Academy of Sciences, add to concerns about proposals to use iron fertilization of the oceans as a way to combat global warming.

Blooms of diatoms in the genus Pseudo-nitschia, which produce a neurotoxin called domoic acid, are a regular occurrence in coastal waters. During large blooms, the algal toxin enters the food chain, forcing the closure of some fisheries (such as shellfish and sardines) and poisoning marine mammals and birds that feed on contaminated fish. But until now, blooms of these algae in the open ocean have attracted little attention from researchers.

"Normally, Pseudo-nitschia cells are sparse in the open ocean, so they don't have much effect. But these species are incredibly responsive to iron, often becoming dominant in algal blooms that result from iron fertilization. Any iron input might cause a bloom of the cells that make the toxin," said Mary Silver, professor emerita of ocean sciences at the University of California, Santa Cruz, and lead author of the new study.

Because both natural and artificial additions of iron to ocean waters cause phytoplankton (single-celled algae) to grow vigorously, and because phytoplankton take up carbon dioxide as they grow, iron fertilization of the oceans has been suggested as way to reduce atmospheric concentrations of carbon dioxide and thereby combat global warming.

"This work definitely reveals a wrinkle in those plans," said coauthor Kenneth Coale, director of Moss Landing Marine Laboratories. "It is much easier to break an ecosystem than it is to fix one. In light of these findings, we should redouble our efforts to reduce carbon emissions, the primary culprit for ocean ecosystem damage worldwide."

In 2007, Silver accompanied Ken Bruland, professor of ocean sciences at UCSC, on a research cruise to study iron chemistry in the Gulf of Alaska. She saw Pseudo-nitschia cells often in samples collected at sea, and analysis of the samples back in the lab showed the presence of the domoic acid toxin. Those findings prompted her to team up with Coale to analyze old samples collected during iron-enrichment experiments conducted in 1995 and 2002. Coale was the principal investigator or chief scientist for these studies.

"We thought the toxin would have broken down, but it was still there," Silver said.

In addition to samples from the two iron-enrichment experiments, the researchers analyzed samples from three natural populations in the North Pacific. The results showed that oceanic waters throughout the Pacific contain Pseudo-nitschia populations associated with the domoic acid neurotoxin.

Silver noted that blooms of Pseudo-nitschia must occur naturally in the open ocean as a result of iron deposited by dust storms, volcanic eruptions, and other airborne sources. "It is a natural phenomenon and likely has been for millions of years," she said. "But those are sporadic occurrences. To do iron enrichment on a large scale could be dangerous because, if it causes blooms of Pseudo-nitschia, the toxin might get into the food chain, as it does in the coastal zone."

In addition to Silver, Coale, and Bruland, the coauthors of the PNAS paper include Sibel Bargu and Ana Garcia at Louisiana State University; Susan Coale and Kathryn Roberts at UC Santa Cruz; and Claudia Benitez-Nelson and Emily Sekula-Wood at the University of South Carolina. This research was funded by the National Science Foundation, U.S. Department of Energy, and U.S. Office of Naval Research.

Tim Stephens | EurekAlert!
Further information:
http://www.ucsc.edu

More articles from Ecology, The Environment and Conservation:

nachricht Scientists team up on study to save endangered African penguins
16.11.2017 | Florida Atlantic University

nachricht Climate change: Urban trees are growing faster worldwide
13.11.2017 | Technische Universität München

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Nanoparticles help with malaria diagnosis – new rapid test in development

The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.

Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

Im Focus: Researchers Develop Data Bus for Quantum Computer

The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.

Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

Previous evidence of water on mars now identified as grainflows

21.11.2017 | Physics and Astronomy

NASA's James Webb Space Telescope completes final cryogenic testing

21.11.2017 | Physics and Astronomy

New catalyst controls activation of a carbon-hydrogen bond

21.11.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>