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Archive for the ‘Oceans’ Category

Are Jellyfish Increasing in World’s Oceans?

February 2, 2012 Comments off

sciencedaily.com

Giant jellyfish clog fishing nets in Japan. (Photo Credit: Shin-ichi Uye)

A global study has questioned claims that jellyfish are increasing worldwide.

Blooms, or proliferation, of jellyfish have shown a substantial, visible impact on coastal populations — clogged nets for fishermen, stinging waters for tourists, even choked intake lines for power plants — and recent media reports have created a perception that the world’s oceans are experiencing increases in jellyfish due to human activities such as global warming and overharvesting of fish. Now, a new global and collaborative study questions claims that jellyfish are increasing worldwide and suggests claims are not supported with any hard evidence or scientific analyses to date.

Dr Cathy Lucas, a marine biologist at the University of Southampton, who is based at the National Oceanography Centre, Southampton was involved in the study, which appears in the latest issue of BioScience. Her co-authors are composed of experts from the Global Jellyfish Group, a consortium of approximately 30 experts on gelatinous organisms, climatology, oceanography and socioeconomics from around the globe, that Read more…

Nasa study solves case of Earth’s ‘missing energy’

January 30, 2012 Comments off

physorg.com

Clouds play a vital role in Earth's energy balance, cooling or warming Earth's surface depending on their type. This painting, "Cumulus Congestus," by JPL's Graeme Stephens, principal investigator of NASA's CloudSat mission, depicts cumulus clouds, which transport energy away from Earth's surface. Image credit: Graeme Stephens

(PhysOrg.com) — Two years ago, scientists at the National Center for Atmospheric Research in Boulder, Colo., released a study claiming that inconsistencies between satellite observations of Earth’s heat and measurements of ocean heating amounted to evidence of “missing energy” in the planet’s system.

Where was it going? Or, they wondered, was something wrong with the way researchers tracked energy as it was absorbed from the sun and emitted back into space?

An international team of and , led by Norman Loeb of NASA’s Langley Research Center in Hampton, Va., and including Graeme Stephens of NASA’s Jet Propulsion Laboratory in Pasadena, Calif., set out to investigate the mystery.

They used 10 years of data — spanning 2001 to 2010 — from NASA Langley’s orbiting Clouds and the Earth’s Radiant Energy System Experiment (CERES) instruments to measure changes in the net at the top of Earth’s atmosphere. The CERES data were then combined with estimates of the heat content of Earth’s from three independent ocean-sensor sources.

Their analysis, summarized in a NASA-led study published Jan. 22 in the Read more…

Giant ocean whirlpools puzzle scientists

April 13, 2011 Comments off

pravda

US scientists discovered two giant whirlpools in the Atlantic Ocean, off the coast of Guyana and Suriname. It became a sensational discovery because this part of the ocean has been studied thoroughly, and no one expected anything like that to appear in the area. More importantly, no one can understand where the whirlpools came from and what surprises they may bring to people.

According to Brazilian scientist Guilherme Castellane, the two funnels are approximately 400 kilometers in diameter. Until now, these were not known on Earth. The funnels reportedly exert a strong influence on climate changes that have been registered during the recent years.

“Funnels rotate clockwise. They are moving in the ocean like giant frisbees, two discs thrown into the air. Rotation occurs at a rate of one meter per second, the speed is Read more…

Large-Scale Assessment Of The Arctic Ocean: Significant Increase In Freshwater Content Since 1990s

March 28, 2011 Comments off

nanopatentsandinnovations

The freshwater content of the upper Arctic Ocean has increased by about 20 percent since the 1990s. This corresponds to a rise of approx. 8,400 cubic kilometres and has the same magnitude as the volume of freshwater annually exported on average from this marine region in liquid or frozen form. This result is published by researchers of the Alfred Wegener Institute in the journal Deep-Sea Research. The freshwater content in the layer of the Arctic Ocean near the surface controls whether heat from the ocean is emitted into the atmosphere or to ice. In addition, it has an impact on global ocean circulation.

Differences in the mean salinity of the Arctic Ocean above the 34 isohaline between 2006 to 2008 and 1992 to 1999.

Negative values are shown in yellow, green, and blue and stand for an increase of freshwater.

Image: Benjamin Rabe, Alfred Wegener Institute Read more…

UA climate research: Big stretch of US coast at risk of rising seas

February 23, 2011 Comments off

azstarnet.com

If global temperatures continue to rise and polar ice continues to melt, 9 percent of the land in our coastal cities and towns will be beneath sea level by the end of the century, University of Arizona researchers say.

Climate researchers Jeremy Weiss and Jonathan Overpeck, along with Ben Strauss of Climate Central in Princeton, N.J., mapped the U.S. coastline, using elevations provided by the U.S. Geological Survey. They applied the most recent predictions of a sea level rise of 1 meter (3.28 feet) by 2100 to produce a map that predicts big trouble for 20 cities with more than 300,000 people and for 160 smaller municipalities.

Weiss is a senior researcher in geosciences. Overpeck is a professor of geosciences and atmospheric sciences and co-director of the UA’s Institute of the Environment.

The report was published last week in Climatic Change Letters.

The biggest impact will be felt in low-lying, heavily populated places such as New Orleans, Miami Beach and Virginia Beach, the report says.

Subsequent centuries will bring even higher sea levels that could completely submerge 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…