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<DIV class="wpn-post-title entry-title article-heading"><A
title="Huge phytoplankton bloom found under Arctic ice"
href="http://blogs.nature.com/news/2012/06/huge-phytoplankton-bloom-found-under-arctic-ice.html"
rel=bookmark><FONT color=#000000 size=4>Huge phytoplankton bloom found under
Arctic ice</FONT></A></DIV>
<DIV class=wpn-byline><TIME datetime="2012-06-07T19:46:35+01:00" pubdate>by
<SPAN class="author vcard"><A class="url fn n" title="nicola jones"
href="http://blogs.nature.com/news/author/nicola-jones-2"><FONT
color=#1f699b>nicola jones</FONT></A></SPAN></DIV>
<DIV class=wpn-byline><SPAN class="author vcard"><SPAN class=published><ABBR
class=value title=2012-06-07>07 Jun 2012 </ABBR></SPAN> </SPAN></DIV>
<DIV class=wpn-byline><SPAN class=divider><A
href="http://blogs.nature.com/news/2012/06/huge-phytoplankton-bloom-found-under-arctic-ice.html?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+news%2Frss%2Fnewsblog+%28News+Blog+-+Blog+Posts%29&WT.ec_id=NEWS-20120612">http://blogs.nature.com/news/2012/06/huge-phytoplankton-bloom-found-under-arctic-ice.html?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+news%2Frss%2Fnewsblog+%28News+Blog+-+Blog+Posts%29&WT.ec_id=NEWS-20120612</A></SPAN></DIV>
<DIV><!-- before_entry --></HEADER><SECTION>
<DIV class="wpn-entry-content content">
<P>Researchers have been shocked to find a record-breaking phytoplankton bloom
hidden under Arctic ice. “It’s much bigger [in concentration] than any natural
open water bloom in the most productive ecosystems in the world,” says Kevin
Arrigo, of Stanford University in California. “The growth rates were
astonishingly high – these cells were doubling more than once every day.”</P>
<P>“I would have told you a year ago that this couldn’t happen in the Arctic,”
says Arrigo. Now, he notes that some 25% of the Arctic Ocean has conditions
conducive to such blooms. The finding implies that the Arctic is much more
productive than previously thought, and might help to explain why Arctic waters
have proven such a good carbon dioxide sink, the researchers say.</P>
<P>As Arctic ice melts earlier in the summer thanks to climate change, these
blooms could grow in extent or happen earlier in the year. The implications of
that are unknown, but it could be bad news for fish that feed on open-water
phytoplankton, or animals that time their summer trips to the Arctic to match
what has traditionally been the peak of phytoplankton blooms. “There’s going to
be winners and losers,” says Arrigo.</P>
<P>Researchers have long assumed that phytoplankton blooms in the Arctic start
in summer, in open waters after the ice melts. In charting this, as part of a
mission to help ‘ground truth’ NASA satellite measures of such blooms, a team of
researchers was making measures in the Chukchi Sea as part of the ICESCAPE
mission of summer 2011. But when they looked under the thin ice, they were
shocked to find a ‘pea soup’ of phytoplankton about 100 km on a side, extending
up to 70 metres deep in places, they report today in the journal <A
onclick="javascript:_gaq.push(['_trackEvent','outbound-article','http://www.sciencemag.org']);"
href="http://www.sciencemag.org/content/early/2012/06/06/science.1215065.abstract?sid=89543397-dddc-4392-9820-acf675c86777"><EM><FONT
color=#1f699b>Science</FONT></EM></A>. The natural concentration of
phytoplankton there is greater than anywhere else Arrigo is aware of — not
including blooms caused by fertilizer runoff in places like the Gulf of Mexico
or the Baltic Sea.</P>
<P>In hindsight the finding makes sense. Shallow Arctic waters are known to be
rich in nutrients like nitrogen. And sea ice is known to be getting <A
onclick="javascript:_gaq.push(['_trackEvent','outbound-article','http://www.agu.org']);"
href="http://www.agu.org/pubs/crossref/2011/2011GL047735.shtml"><FONT
color=#1f699b>thinner </FONT></A>– in the mid-1980s, about 75% of Arctic spring
ice was thick ‘multi-year’, which is often about 3 metres thick; but by 2001
that had plummeted to 45%. Ice that forms and melts in a single year is often
just a meter thick. That thinner ice, and the melt ponds that form on top of it
in spring, act like a skylight to let light into the waters below, while still
blocking out harmful ultraviolet rays. The result is perfect growing conditions
for phytoplankton. “If I were a phytoplankton that’s where I would want to
grow,” says Arrigo.</P>
<P>The researchers guess that the blooms seen previously in open Arctic waters
were not the beginnings of phytoplankton season, as previously thought, but the
tail, dying end of it.</P></DIV></FONT></DIV><BR>
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