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November 2011 Issue

Insitu Tests Marine Mammal Tracking With ScanEagle UAS
Insitu Pacific (Queensland, Australia) said in October that it had concluded the second phase of a trial to determine if unmanned aircraft systems (UAS) are a cost-effective, capable alternative to manned assets for surveying marine mammals.

During a two-week operation conducted in partnership with Murdoch University, Insitu Pacific's ScanEagle UAS captured up to 3,000 images of humpback whales daily. The trial demonstrated ScanEagle's ability to operate effectively in Class G commercial airspace, a step toward expanding civil airspace to incorporate more unmanned systems, the company said.

Able to fly for more than 24 hours at a time on less than five quarts of fuel, the runway-independent ScanEagle was launched, controlled and retrieved from North Stradbroke Island off the coast of Queensland. A high-resolution digital still camera was fitted alongside a typical ScanEagle electro-optic payload. Previous field trials in October 2010 were conducted in Western Australia.

"Flying for a long time, at a low altitude, well off the coast is a high-risk mission for a manned aircraft. Unmanned systems offer an alternative," Insitu Pacific Managing Director Andrew Duggan said.

For more information, visit www.insitu.com.

Study: Surviving 'Snowball Earth' Needed Red Sea-Like Conditions
Global glaciation likely put a chill on life on Earth hundreds of millions of years ago, but new research indicates that photosynthetic algae could have survived in a narrow body of water with characteristics similar to today's Red Sea.

"Under those frigid conditions, there are not a lot of places where you would expect liquid water and light to occur in the same area, and you need both of those things for photosynthetic algae to survive," said Adam Campbell, a University of Washington doctoral student.

A long, narrow body of water such as the Red Sea would create enough physical resistance to advancing glacial ice that the ice sheet likely could not make it all the way to the end of the sea before conditions would cause the ice to turn to vapor. That would leave a small expanse of open water where the algae could survive. Campbell examined the issue using a model that applied basic principles of physics to a set of atmospheric conditions believed to have existed at the time. The results were published in October in Geophysical Research Letters.

Many scientists believe Earth became a giant snowball two or three times between 800 million and 550 million years ago, with each episode lasting about 10 million years. Plankton turn up in the fossil record before and after these events.

Campbell said it is assumed the algae survived these episodes, "unless they re-evolved each time, which creates a whole different problem for evolutionary biology." Campbell noted that in a snowball Earth event, the open water in such a sea would not have lasted long if it did not have a way of being replenished. The open water had to exist on the order of 10 million years for the algae to survive. For more information, visit www.sciencedaily.com.

Plankton's Shifting Role in Carbon Storage Explored
The phytoplankton Emiliania huxleyi plays an outsized role in drawing carbon from the atmosphere and sequestering it deep in the seas, but this role may change as the ocean becomes warmer and more acidic, according to a San Francisco State University (SFSU) research team.

In a study published in October in Global Change Biology, SFSU assistant professor of biology Jonathon Stillman and colleagues show how climate-driven changes in nitrogen sources and CO2 levels in seawater could make Emiliania huxleyi a less effective agent of carbon storage.

Stillman and his colleagues raised more than 200 generations of Emiliania huxleyi in the lab, adjusting CO2 levels and the type of nitrogen in the seawater bath. They found that high levels of CO2, along with a shift in the prevailing nitrogen type from nitrates to ammonium, "had a synergistic effect" on the phytoplankton's biology and growth. In particular, carbon-storing coccoliths formed under conditions of high CO2 and high ammonium levels were incomplete or hollow, and contained less than the usual amount of inorganic carbon.

Emiliania huxleyi typically use nitrates to make proteins, but this form of nitrogen may be in shorter supply, as a thickening layer of warmer surface water could inhibit open-ocean upwelling. At the same time, the warmer temperatures favor bacteria that turn recycled nitrogen from surface waters and the atmosphere into ammonium, and acidification inhibits the bacteria that turn ammonium into nitrate. For more information visit www.sfsu.edu.

Marine Bacterial Communication Could Affect Climate, Study Says
Woods Hole Oceanographic Institution (WHOI) scientists have discovered bacterial communication could have a significant impact on the planet's climate.

In the ocean, bacteria coalesce on tiny particles of carbon-rich detritus sinking through the depths. WHOI marine biogeochemists Laura Hmelo, Benjamin Van Mooy and Tracy Mincer found these bacteria send out chemical signals to discern if other bacteria are in the neighborhood. If enough of their cohorts are nearby, the bacteria secrete enzymes that break up the carbon-containing molecules. Hmelo and her colleagues have uncovered the first proof of this in the ocean. The paper was published in October in Environmental Microbiology Reports.

The source of carbon in the particles is atmospheric CO2. Bacterial communication could lead to the release of carbon from the particles at shallower depths, rather than sinking to the ocean's depths.

According to the WHOI scientists, this means that bacterial communication results in less carbon dioxide being drawn out of the air and transferred to the bottom of the ocean from where it cannot easily return to the atmosphere. For more information, visit www.whoi.edu.


2012:  JAN | FEB | MARCH | APRIL | MAY | JUNE | JULY | AUG | SEPT | OCT | NOV | DEC
2011:  JAN | FEB | MARCH | APRIL | MAY | JUNE | JULY | AUG | SEPT | OCT | NOV | DEC

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