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Ocean Research


April 2012 Issue

NOAA Prepares for Possible Elimination of NRT
NOAA began preparing in March to phase out its navigation response team (NRT) program, which could be eliminated in a proposed $2.3 million cut in the fiscal year (FY) 2013 budget. If the budget is approved, the NRT would terminate on September 30. This would mean that there would be no more nautical chart updates for high-transit coastal areas, such as Savannah and Brunswick, Georgia; Mobile, Alabama; Biloxi, Mississippi; portions of the Texas coast and Long Beach; Thunder Bay, Michigan; the eastern Long Island Sound; and Narragansett Bay.

The NRT validates approximately 9,000 navigational chart features annually and is responsible for finding and reporting dangerous features to the maritime community. The program monitors seafloor conditions and provides first responders in the event of maritime emergencies, making it an important service for high-traffic port and coastal areas.

Ports and the commercial shipping industry may need to make alternate emergency response plans if the NRT is terminated, the agency said. NOAA navigation managers will discuss with maritime stakeholders how to meet their nearshore survey needs after the NRT's possible termination.

Hurricane season does not end until November 30 in the Southeast and Gulf coasts. NOAA suggests affected areas should consider that the NRT may not be available for assistance in the final months of the season. For more information click here.

Scientists Agree Sea Level Is Rising But Predictions Vary
Sea levels could rise 40 to 70 feet higher than at present in future generations, according to research results published in March. The researchers examined rock and soil cores in Virginia, Eniwetok Atoll in the Pacific and New Zealand dating from the late Pliocene epoch, 2.7 million to 3.2 million years ago, the last time the carbon dioxide level in the atmosphere was at today's levels. Atmospheric temperatures back then were also 2° C higher than present.

For the 21st century, global sea level is on track to rise 2 to 3 feet due to the warming of the oceans and the partial melting of mountain glaciers, and Greenland and Antarctic ice, Kenneth G. Miller, one of the researchers and professor at Rutgers University, said.

'The natural state of the earth with present carbon dioxide levels is one with sea levels about 20 meters higher than at present,' Miller said.

Another study published in Nature in March estimates ancient sea levels rose 20 to 43 feet higher than today. Researchers hope to use this estimation to pinpoint future sea-level rise predictions. The study looked at where shorelines stood on cliffs and reefs in Bermuda and the Bahamas 400,000 years ago during an extremely warm period with the goal of narrowing the range of projected future global sea levels. The seas reportedly rose 20 to 30 feet higher than today; a third less than previous estimates. The Greenland and West Antarctic ice sheets collapsed back then, but not the larger East Antarctic Ice Sheet.

Jerry Mitrovica, the study's co-author, cautioned: 'Bermuda and the Bahamas are not a pristine measure of the volumes of ice that melted in the past, because they're contaminated by effects left over from the ice ages.' Researchers will sample old shorelines in South Africa and Kenya this summer to gather more data on ancient sea levels. Click here for more information.

Japanese, German Researchers To Investigate Tohoku Quake
German and Japanese scientists will conduct an expedition in March and April to investigate the traces of the magnitude-9 Tohoku earthquake on the seafloor. They will use the German RV Sonne and deploy other marine technologies to up to 7,000 meters depth.

During two trips, 33 scientists will deploy two deep-sea observatories in boreholes drilled during earlier expeditions to help record future earthquakes. The AUV MARUM-SEAL will be deployed to map the seafloor with its multibeam sonar at more than 2,000 meters deep. The RV Sonne will map profiles from the shelf off Honshu across the deep-sea trench with its echosounders, to be compared with earlier maps for changes in seafloor topography caused by the Tohoku quake.

During the second leg, samples will be taken at more than 7,000 meters deep from the bottom of the Japan trench to find out how much sediment was transported into the trench during and after the quake.

The Tohoku quake shifted a segment of the Honshu coast east by up to 5 meters. Displacements exceeding 50 meters were registered at the Japan deep-sea trench's edge. The seafloor rose up to 5 meters in a 15,000-square-kilometer area, and subsea landslides moved large volumes of rock into the Japan trench. Click here for more information.

Sea Ice Decline Triggers Bromine, Mercury Release
Drastic melting of Arctic sea ice in the last decade could be increasing bromine release into the atmosphere, resulting in ozone depletion in the troposphere and toxic mercury deposits in the Arctic, a NASA-led study found.

The research examined bromine explosions, which occur when the salt in sea ice interacts with frigid temperatures and sunlight. The ice releases bromine, triggering a cascade of chemical reactions, or a bromine explosion, that rapidly creates more molecules of bromine monoxide in the atmosphere, which reacts with mercury gas. The mercury then falls to the Earth's surface as a pollutant.

Bromine can also remove ozone from the lowest layer of the atmosphere, the troposphere. When ozone is in the higher stratosphere, it blocks harmful radiation, but in the troposphere, at ground-level, it is a pollutant.

Data came from six satellites, field observations and a model of atmospheric air movement to link Arctic sea ice changes to bromine explosions over the Beaufort Sea, extending to the Canadian Arctic's Amundsen Gulf.

'Shrinking summer sea ice has drawn much attention to exploiting Arctic resources and improving maritime trading routes,' Son Nghiem, leader of the study team who works for NASA's Jet Propulsion Laboratory, said. 'But the change in sea ice composition also has impacts on the environment. Changing conditions in the Arctic might increase bromine explosions in the future.' For more information click here.


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