Archive

Posts Tagged ‘Artic Ocean’

Rising Oceans – Too Late to Turn the Tide?

July 15, 2011 1 comment

uanews.org

(Click to enlarge) If sea levels rose to where they were during the Last Interglacial Period, large parts of the Gulf of Mexico would be under water (red areas), including half of Florida and several Caribbean islands. (Photo illustration by Jeremy Weiss)

By Daniel Stolte, University Communications July 14, 2011
Melting ice sheets contributed much more to rising sea levels than thermal expansion of warming ocean waters during the Last Interglacial Period, a UA-led team of researchers has found. The results further suggest that ocean levels continue to rise long after warming of the atmosphere has leveled off.

Thermal expansion of seawater contributed only slightly to rising sea levels compared to melting ice sheets during the Last Interglacial Period, a University of Arizona-led team of researchers has found.

The study combined paleoclimate records with computer simulations of Read more…

World’s Oceans In ‘Shocking’ Decline

June 21, 2011 Comments off

bbc

Coral and fishThe oceans are in a worse state than previously suspected, according to an expert panel of scientists.

In a new report, they warn that ocean life is “at high risk of entering a phase of extinction of marine species unprecedented in human history”.

They conclude that issues such as over-fishing, pollution and climate change are acting together in ways that have not previously been recognised.

The impacts, they say, are already affecting humanity.

The panel was convened by the International Programme on the State of the Ocean (IPSO), and brought together experts from different disciplines, including coral reef ecologists, toxicologists, and fisheries scientists.

Its report will be formally released later this week.

“The findings are shocking,” said Alex Rogers, IPSO’s scientific director and professor of conservation biology at Oxford University.

“As we considered the cumulative effect of what humankind does to the oceans, the implications became far worse than we had individually realised.

“We’ve sat in one forum and spoken to Read more…

Arctic Sea-Ice Controls the Release of Mercury

January 23, 2011 1 comment

Mercury is the most high profile atmospheric contaminant entering the Arctic because it is a potent neurotoxin that biomagnifies in food webs. In the troposphere (lower atmosphere) it is primarily present in the form of gaseous elemental mercury. Photochemical reactions during the Arctic spring (Figure 1) combine salts from sea ice and the gaseous mercury in the air to create an oxidized reactive form of mercury. This mercury is then deposited to snow and ice. These deposition events require salty sea ice and snow crystal surfaces so they are widespread in the Polar Regions.

Mercury (Hg) is the only heavy metal that is essentially found in gaseous form in the atmosphere. Since the industrial revolution, emissions of anthropogenic Hg resulting from the combustion of fossil fuels have exceeded natural emissions. Both anthropogenic emissions and natural emissions (which mainly stem from the oceans and gases released by volcanoes) reach the Polar Regions under the action of atmospheric currents. In this way, fallout from global atmospheric pollution contributes to depositing mercury in Arctic ecosystems, even though these are far away from major anthropogenic emission sources. Read more…