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Phytoplankton flourishes as Kasatochi’s ash fertilizes the ocean 8 October 2010

Posted by admin in Alaska, current research, Kasatochi.
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The eruption of Alaska’s Kasatochi volcano in August 2008 has led to a surge in the population of phytoplankton in the North Pacific, says a paper in Geophysical Research Letters authored by a horde of scientists from institutions in Canada, the USA and the UK, led by oceanographer Roberta C. Hamme of the University of Victoria, British Columbia. An unusual storm system meant that the ash deposited by the volcano was transported across a very wide area of the north-eastern Pacific, and the iron content encouraged the growth of phytoplankton (for which iron is a key nutrient), producing one of the largest plankton blooms ever recorded in this region. Scientists have recently suggested that volcanic ash fertilization of the ocean in this way can occur, but, as Professor Hamme notes in the very useful summary of the Kasatochi paper she has made available as a PDF on her website (wish more scientists would do that), this is the first time conclusive evidence has been obtained to support the hypothesis.

Because phytoplankton (which are the basis of oceanic and freshwater food chains) consume carbon dioxide and release oxygen, seeding the oceans with iron to encourage their growth has sometimes been suggested as a means of diminishing atmospheric CO2. However, the evidence of the naturally-occurring Kasatochi seeding episode is that the process is not very efficient and that it would take a lot of iron to make even a small difference.

  • Roberta C. Hamme et al. ‘Volcanic ash fuels anomalous plankton bloom in subarctic northeast Pacific’, Geophysical Research Letters, 37 (2010), doi:10.1029/2010GL044629. [abstract]

News
How volcanoes feed plankton – ScienceNow, 5 October 2010
Effects of volcanic eruption dash promising global warming theoryGlobe and Mail, 5 October 2010
Volcano ‘seeded’ ocean bloom – UPI.com, 6 October 2010

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Seamounts galore in Oceanography special issue 24 February 2010

Posted by admin in current research, submarine volcanism.
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Oceanography special issue: Mountains in the Sea (23:1 Mar 2010)

The latest issue (vol. 23, no. 1, March 2010) of the official magazine of The Oceanography Society, Oceanography, is devoted to the study of undersea mountains or seamounts. This special issue is entitled, not surprisingly, ‘Mountains in the Sea’ and features fascinating content by some very distinguished contributors, and, best news of all, the online version is free!

Seamount volcanism is an important theme in many of the articles, as might be expected. The following focus particularly on volcanic matters (links are direct to the PDFs):

There are also spotlight articles on particular seamounts, including the volcanically active Loihi, Vailulu’u and Northwest Rota-1 seamounts (links are direct to the PDFs).

The table of contents for this special issue of Oceanography gives direct links to all the content, and USGS director Marcia McNutt provides a foreword (PDF). Also: Oceanography home page, The Oceanography Society home page, and a press release at ScienceDaily.

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British scientists to investigate Caribbean deep-sea hydrothermal vents 10 August 2008

Posted by admin in Caribbean, current research, geoscience, submarine volcanism, volcanology.
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RRS James Cook at the National Oceanography Centre, Southampton (Image credit National Oceanography Centre, Southampton) 

Using the latest in deep-sea exploration technology, British scientists are to investigate the world’s deepest undersea volcanic ridge, 6000 metres down at the bottom of the Cayman Trough in the Caribbean. The United Kingdom’s newest dedicated scientific research vessel, RRS James Cook, will devote two month-long cruises to exploring the Cayman Trough, employing the remotely-operated Isis submarine and the autonomous underwater vehicle Autosub6000.

The scientific team is led by Dr John Copley of the National Oceanography Centre, Southampton, where RRS James Cook is based. The primary focus of the project is the study of the geochemistry and biology of undersea volcanic vents, and the investigation of hydrothermal processes where the Earth’s mantle is directly exposed to seawater. Hydrothermal vents in such cases, says Dr Copley, ‘could be hotter than 500C (930F), and if they are that hot, they will probably have quite different chemistry and life forms – we expect to find new species’.

Image: RRS James Cook at the National Oceanography Centre, Southampton (credit: National Oceanography Centre, Southampton, used with permission).

News
Sub to make deep Caribbean dive – BBC News, 9 August 2008
Robot submarine to dive deep in the Caribbean – ZDNet.com, 10 August 2008

Information
National Oceanography Centre, Southampton – the UK centre for oceanographical research
RRS James Cook – information from the National Oceanography Centre
RRS James Cook Homepage – an unofficial site by a member of the James Cook technical team

The Volcanism Blog