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Environmental Monitoring


September 2014 Issue

Southern sea ice Expansion May be Data Processing Fluke
Scientists from Scripps Institution of Oceanography and NASA said that much of the increase in measurement for Southern Hemisphere sea ice could be due to a processing error in the satellite data.

Arctic sea ice is retreating at a dramatic rate. In contrast, satellite observations suggest that sea ice cover in the Antarctic is expanding at a moderate rate and that sea ice extent has reached record highs in recent years. Whatís causing Southern Hemisphere sea ice cover to increase in a warming world has puzzled scientists.

Satellite data have been used to measure sea ice cover for 35 years, but the data donít come from a single instrument on a single satellite. Instead, researchers splice together observations from different instruments flown on a number of different satellites. They then use an algorithm and further processing to estimate sea ice cover from these data.

The scientists compared two data sets for sea ice measurements and found a difference related to a transition in satellite sensors in December 1991 and the way the data collected by the two instruments were calibrated. It appears that one of the records did this calibration incorrectly, introducing a step-like change in December 1991 that was big enough to have had a large impact on the long-term trend.

MTS Announces Winners of ROV Scholarships
Justin Burnett, Riley Wilbur, John Lutchko and Kip Hacking have been selected as recipients of the Marine Technology Societyís 2014 ROV Committee Scholarships. Burnett was awarded $10,000; Wilbur was awarded $7,500; Lutchko received $5,000; and Hacking received $2,500.

In addition, Brian Grau, Wesley Ivester, Camille Pagniello and Nicholas Sopwith received MTS ROV Committee MATE Center Scholarships. Grau was awarded $10,000; Ivester was awarded $7,500; Pagniello received $5,000; and Sopwith received $2,500.

Scientists Find Iceberg Traces in Arctic Seafloor
Scientists from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI) have found scours left behind on the seabed by gigantic icebergs between Greenland and Spitsbergen. The five lineaments, at 1,200 meters depth, are the lowest-lying iceberg scours found on the Arctic seafloor.

They provide new understanding of the dynamics of the Ice Age and the extent of the Arctic ice sheet thousands of years ago.

The researchers could also draw conclusions about the export of freshwater from the Arctic to the North Atlantic. In the past, some scientists assumed that thick sea ice was primarily responsible for freshwater export from the Arctic.

The newly discovered scours, however, suggest large icebergs drifted southward through the Fram Strait, carrying large volumes of frozen freshwater into the North Atlantic.

PML Creates Buoy Solution for Ocean Gas Measurements
Gas transfer across the air-sea interface is a major link in global chemical cycles. Knowing which gases are being absorbed or emitted by the ocean, how the quantities change seasonally and how much gas is moving across the sea surface is crucial to understanding how these cycles work and how global climate may be affected.

Assessing dissolved gas concentration gradients close to the sea surface requires good depth precision. The traditional jib-mounted method of lowering instruments into the sea cannot provide this, except in the rare event of a very calm sea state. Plymouth Marine Laboratoryís (PML) new Near Surface Ocean Profiling Buoy enables accurate measurements from the top few meters of the ocean by suspending instruments below a floating buoy, which rises and falls with the swell, so measurements can be taken at a constant depth.

The platform can be lowered into the sea and left to drift away from the mother ship. Instrument sampling depth is remotely controlled by a winch and tubing back to the mother ship, enabling sample seawater to be pumped aboard for analysis. A tether retrieves the buoy for loading before moving to the next sampling location.

The buoy will make its research debut on a cruise into the Celtic Sea.

Hyde Marine to use NIOZ B-box to Analyze Ballast Water
Hyde Marine, Inc. (Pittsburgh, Pennsylvania) will begin using a new ballast water test system, B-box, recently made available from the Royal Netherlands Institute for Sea Research (NIOZ), to help ballast water treatment (BWT) technology companies analyze concentrations of chemicals or organisms in ballast water.

NIOZ extensively tested the B-box system with Hyde Marine over the past two years to determine its efficacy for maritime use, and to further test the real-world performance of the Hyde GUARDIAN Gold BWT system.

B-box is a ballast water sampling box with sample bottles that can be filled with treated ballast water, mixed with provided test chemicals, and sent to NIOZ for tests on physical-chemical variables and concentrations of organisms as requested by Hyde Marine. Hyde Marine-trained service personnel can be used to take the samples and prepare them for shipment.

Gulf of Mexico Dead Zone Confirms Hypoxia Models
NOAA- and EPA-supported scientists have mapped the Gulf of Mexico dead zone, an area with low-oxygen water, measuring 5,052 square miles this summer. This falls in the predicted range of 4,633 to 5,708 square miles forecast by NOAA-sponsored models, and confirms the accuracy of the models and their utility for guiding management of nutrients in the Mississippi River watershed.

The size is smaller than the 5,840 square miles recorded last year, but still greater than the Mississippi River/Gulf of Mexico Watershed Nutrient (Hypoxia) Task Force target of less than 1,900 square miles—meaning nutrients from the Mississippi River watershed are continuing to affect U.S. coastal resources and habitats in the Gulf. The hypoxic zone off the coast of Louisiana and Texas forms each summer, threatening the ecosystem that supports valuable commercial and recreational Gulf fisheries.


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