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December 2012 Issue

Antarctic Sea Ice Drift Shown To Cause Sea Ice Cover Increase
NASA and British Antarctic Survey scientists have reported in Nature Geosciences in November the first direct evidence that changes to Antarctic sea ice drift, caused by changing winds, are responsible for increases in Antarctic sea ice cover in the past two decades. This helps explain why Antarctic sea ice cover has increased under the effects of climate change.

Research scientists Ron Kwok of NASA’s Jet Propulsion Laboratory (JPL) and Paul Holland of the Natural Environment Research Council’s British Antarctic Survey used maps created by JPL from more than 5 million daily ice-motion measurements. The data, captured over a period of 19 years by four U.S. satellites, show for the first time long-term changes in sea ice drift around Antarctica.

“The total Antarctic sea ice cover is increasing slowly, but individual regions are actually experiencing much larger gains and losses that are almost offsetting each other overall,” Holland said. These regional changes are caused by wind changes, which affect the ice cover through changes in ice drift and air temperature.

“The changes in ice drift also suggest large changes in the ocean surrounding Antarctica, which is very sensitive to the cold and salty water produced by sea ice growth,” he said.

Increased northward winds have caused the sea ice cover to expand outwards from Antarctica in regions.

The Arctic, by contrast, has been losing sea ice dramatically, but the Arctic Ocean is surrounded by land, so changed winds cannot cause Arctic ice to expand in the same way as what is occurring with Antarctic sea ice.

The new research will improve understanding of present and future climate change.


One-Third of Marine Species Yet To Be Discovered, Study Finds
There are fewer than 1 million marine species on the planet, lower than some previous estimates, with about one-third still undiscovered, according to a study published in November in Current Biology.

Hot spots for finding new species include deep-sea ecosystems and tropical areas, said researcher Mark Costello from the University of Auckland.

“If we look at the number of undescribed species and samples from around the world, especially deep-sea and tropical areas, the average over 100 studies was that about 30 percent of those new species were new to science,” Costello told The New Zealand Herald.

New species found in the past year include Yoda purpurata in the North Atlantic, named after the “Star Wars” Jedi master, a crimson shrimp at 2,600 meters depth in the Norwegian Sea and a bristle worm at 1,600 meters below the northeast Pacific.

Complementing this research, the World Register of Marine Species is an open-access, online database that has received contributions from almost 300 scientists from 32 countries.

Species research enables more accurate estimates of extinction rates through habitat loss.

Around 226,000 species have been described by science and up to 72,000 more have yet to be described.

The rate of discovery for new species is increasing, with an unprecedented 20,000 new marine species described in the past decade, suggesting that most marine species will be discovered this century, the Herald reported.

Many of the species yet to be discovered will come from among the smaller crustaceans, molluscs, algae, worms and sponges.


Humans, Not Natural Phenomena Linked to Ocean Salinity Changes
Changes in ocean salinity over the second half of the 20th century are consistent with the influence of human activities and inconsistent with natural climate variations, according to a study published in Geophysical Research Letters in November.

The study builds on previous analyses in the last decade that demonstrated that rising temperatures in the upper 700 meters of the ocean can only be explained by anthropogenic climate change, caused mostly by an accumulation of carbon dioxide created by fossil-fuel use.

This study used the detection and attribution method, with observed trends in ocean salinity being compared to the effects of various historical phenomena such as volcanic eruptions or solar fluctuations and to climate cycles such as El Niño.

When the computer climate models were run, the influence of those phenomena did not replicate the salinity or temperature patterns that researchers have observed since 1955. Only when the warming trends associated with human activity were added could the observed salinity trends and temperature changes be explained.

Ocean salinity changes are driven by global evaporation and rainfall patterns, which are also changing. Observations over recent decades have found a general intensification of salinity differences, with salty ocean regions experiencing more evaporation of surface waters and relatively fresh regions becoming more diluted with precipitation. 


UK Antarctic, Oceanography Centers Will Remain Part of NERC
The British Antarctic Survey and National Oceanography Centre will remain centers of the Natural Environment Research Council (NERC).

NERC met in November to discuss the proposed merger of the British Antarctic Survey and the National Oceanography Centre. After considering feedback from the public, government, polar affairs community, scientists and NERC staff, the council decided not to proceed with the proposal for merger.

NERC has already committed to maintain the funding of the British Antarctic Survey at £42 million a year for the rest of this spending review period.

“Looking to the future—though without pre-empting the timing and size of the next spending review settlement—I consider that NERC should have a discrete funding line for Antarctic infrastructure and logistics from within the ring-fenced science budget to ensure a visible U.K. commitment to maintaining Antarctic science and presence,” David Willetts, minister of state for universities and science, said in a statement. NERC will consider ways forward in light of this comment.



2013:  JAN | FEB | MARCH | APRIL | MAY | JUNE | JULY | AUG | SEPT | OCT | NOV | DEC
2012:  JAN | FEB | MARCH | APRIL | MAY | JUNE | JULY | AUG | SEPT | OCT | NOV | DEC

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