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Environmental Monitoring


June 2011 Issue

Marine Maps Provide Detailed View of the North Sea
A consortium of scientists published in March a study of the U.K.'s east coast marine environment, The East Coast Regional Environmental Characterisation (EC REC).

Led by the Centre for Environment, Fisheries & Aquaculture Science, researchers on the Cefas Endeavour, mapped the seafloor, revealing distinct areas in terms of their physical properties and associated biological communities. Combining the resulting evidence with existing data, the EC REC researchers produced a series of maps of the seabed off East Anglia.

Researchers said they encountered a number of nationally rare or scarce species in the area surveyed, for instance, the rare mantis shrimp (Rissoides desmaresti). Discovery of this species in the area represents a new scientific record, extending the known range of this shrimp to the east coast of England from what was previously thought to be a relatively confined area on the south and Welsh coasts of the U.K. For more information, visit www.cefas.defra.gov.uk.

Global Survey Spots Hundreds of Unknown Barrier Islands
Earth has 657 more barrier islands than previously thought, according to a new global survey by researchers from Duke University and Meredith College. The researchers identified a total of 2,149 barrier islands worldwide using satellite images, topographical maps and navigational charts. The new total is higher than the 1,492 islands identified in a 2001 survey conducted without the aid of publicly available satellite imagery.

The 2,149 barrier islands, which measure 20,783 kilometers in length, are found along all continents except Antarctica and in all oceans. The islands make up roughly 10 percent of Earth's continental shorelines. The survey results appeared in an April edition of the Journal of Coastal Research.

The nation with the most barrier islands is the United States, with 405, including those along the Alaskan Arctic shoreline.

The 657 newly identified barrier islands have long existed but were overlooked or misclassified in past surveys, said Matthew L. Stutz, assistant professor of geosciences at Meredith.

Previously, for instance, scientists believed barrier islands couldn't exist in locations with seasonal tides of more than four meters. Yet the survey, produced by Stutz and Duke professor Orrin Pilkey, identifies the world's longest chain of barrier islands along a stretch of the equatorial coast of Brazil, where spring tides reach seven meters.

Stutz and Pilkey said the survey's findings illustrate the need for a new way to classify and study barrier islands, one that takes into account the complex interplay of local, regional and global variables that shape where the islands form and how they evolve.

The potential for climate and sea level change this century "underscores the need to improve our understanding of the fundamental roles these factors have played historically in island evolution, in order to help us better predict future impacts," Pilkey said. For more information, visit http://today.duke.edu.

Inorganic Mercury Converted to its Most Toxic Form in Oceans
A relatively harmless inorganic form of mercury found in ocean water is transformed into a potent neurotoxin in the seawater itself, according to a University of Alberta–led study published in Nature Geoscience in April.

After two years of testing water samples across the Arctic Ocean, researchers with the study found that relatively harmless inorganic mercury, released from human activities like industry and coal burning, undergoes a process called methylation and becomes deadly monomethylmercury.

Unlike inorganic mercury, mono?methylmercury is bioaccumulative, so its toxic effects are amplified as it progresses through the food chain. The greatest exposure for humans to monomethylmercury is through sea?food. The researchers believe the methylation process happens in oceans all over the world and that the conversion is carried out by microbial life–forms in the ocean.

The research team, led by recent University of Alberta biological sciences Ph.D. graduate Igor Lehnherr, incubated seawater samples collected from the Canadian Arctic Archipelago. Lehnherr says this conversion of inorganic mercury accounts for approximately half of this neurotoxin present in polar marine waters and could account for a significant amount of the mercury found in Arctic marine organisms. The researchers say this is the first direct evidence that inorganic mercury is methylated in seawater. For more information, visit www.expressnews.ualberta.ca.

World's Largest Ocean Radar Network Monitors Coasts
A network of high–frequency radar systems, designed for mapping ocean surface currents, is now providing detailed data on coastal ocean dynamics along the U.S. West Coast.

University of California, Santa Bar?bara (UCSB), is part of the multi–institution research consortium that created the radar network, which has grown over the last decade to what is now considered the largest network of its kind in the world. The 78 radar antennas cover 1,500 miles of shoreline, from Astoria, Washington, to Tijuana, Mexico. The system was completed over the past five years, and a study using the system was reported in March in the Journal of Geophysical Research—Oceans.

Each of the 78 sites has transmit and receive antennas. The transmit antenna sends out radio waves over the ocean surface. By looking at the returned signals, the scientists can determine the speed and direction of currents over large areas of the ocean's surface.

The researchers can observe "coastal trapped waves" with the radar network. These are waves that travel along the coast and can last for periods of several days to a few weeks, unlike wind waves and ocean swells that have periods of about seven to 20 seconds. They are long waves that are caused by wind and come from as far south as Baja California.

The researchers performed a multiyear synthesis of surface current observations, provided through a centralized data center designed and operated by Scripps Institution of Oceanography in support of NOAA's Integrated Ocean Observing System. For more information, visit http://scrippsnews.ucsd.edu.

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