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In This Issue

• Follow the BLUE Ocean Film Fest
• Almost 80 Percent of Oil from Spill Could Remain in Gulf
• Fewer Phytoplankton May Mean Fewer Hurricanes
• Ice-Free Arctic Ocean May Not Be Carbon Sink

Follow the BLUE Ocean Film Fest

The BLUE Ocean Film Festival, presented by the Monterey Bay Aquarium, begins August 24, the first day in a six-day spectacle bringing together filmmakers and film aficionados as well as leaders in ocean research and conservation. In addition to the many ocean-themed movies that will be screened—including Disneynature's epic documentary "Oceans" —the festival will feature conservation lectures, a forum on the Gulf of Mexico oil spill hosted by marine conservationist Carl Safina and unique, in-the-field training events for filmmakers and photographers. SeaWeb will be blogging from the festival at seawebvoicesinaction.blogspot.com/

Science in the News

Almost 80 Percent of Oil from Spill Could Remain in Gulf

A new study has concluded that even if 10 percent of the oil from the Deepwater Horizon accident has been burned or skimmed, almost 80 percent remains beneath the surface. Jeffery Tilghman Williams, U.S. Navy/Marine Photobank

Up to 79 percent of the oil released into the Gulf of Mexico from the Deepwater Horizon well has not been recovered and remains a threat to the ecosystem, according to a report released last week by Georgia Sea Grant and the University of Georgia.

The report strongly contradicts assertions by Carol Browner, climate change and energy adviser to the White House, that 75 percent of the oil had disappeared from the Gulf. Browner said on "Good Morning America" on August 4 that "The scientists are telling us about 25 percent was not captured or evaporated or taken care of by mother nature."

"One major misconception is that oil that has dissolved into water is gone and, therefore, harmless," said Charles Hopkinson, director of Georgia Sea Grant and one of the new report's authors. "The oil is still out there, and it will likely take years to completely degrade. We are still far from a complete understanding of what its impacts are."

"I have not seen data that leads me to conclude that 50 percent of the oil is gone," said Samantha Joye, another of the report's authors, during a conference call with reporters. "No one's standing up here and saying 'this is a doom and gloom scenario,' but at the same time it's not as straight forward as saying all the oil is gone either," she added. "What we're trying to point out is the impacts of oil are still there. There's oil in the water, there's oil on the seafloor, there are going to be impacts on the system. We have to continue monitoring and evaluating what those impacts are."

The authors analyzed data from the National Incident Command Report on which Browner based her claims. Accepting the Obama Administration's statements that 10 percent of the oil from the spill had been burned or skimmed, it then considered the other 90 percent. They wrote: "The NIC report states that oil released into the water, that has not been contained by skimming or burning, is currently in one of four states: 1) dispersed as micro-droplets, 2) dispersed as micro-droplets with dispersant coating, 3) dissolved (some of which has evaporated) and 4) residual.

"Together, these forms make up the unrecovered 90 percent. The news media's tendency to interpret 'dispersed' and 'dissolved' as 'gone' is wrong. Dispersed and dissolved forms can be highly toxic. Furthermore, sorting the oil into the four above states falls far short of assessing how much of it remains a potential threat to the system."

On the same day as the University of Georgia and Georgia Sea Grant released their report, the University of South Florida (USF) announced that its researchers had determined oil from the Deepwater Horizon had settled on the sea floor farther east than predicted. The USF report stated that the oil was spread out in "small, unevenly distributed droplets," in the DeSoto Canyon, a channel on the ocean floor 40 miles from the Florida Panhandle that comprises part of the spawning grounds for much of the Gulf's commercial fish. "To date, this is the easternmost location for the occurrence of subsurface oils," the report stated.

For Further Information: The University of Georgia/Georgia Sea Grant report is available at http://uga.edu/aboutUGA/joye_pkit/GeorgiaSeaGrant_OilSpillReport8-16.pdf.

Contact: Samantha Joye, Department of Marine Sciences, University of Georgia. E-mail: mjoye@uga.edu

For Further Information: Stay on top of the latest information about the spill by visiting SeaWeb's Deepwater Horizon Oil Spill Comprehensive Resource Center, providing news updates, SeaWeb briefings and links to external resources.

Science Briefs

Fewer Phytoplankton May Mean Fewer Hurricanes

Declines in phytoplankton could lead to reductions in tropical storms such as Hurricane Kenna, photographed by satellite off Mexico in 2002. NASA, MODIS Rapid Response Project, NASA/GSFC

As the United States braces for the peak of hurricane season—which several research institutions, including the National Oceanic and Atmospheric Administration (NOAA), have predicted this year's will be an especially active one—a new study has found that a change in the amount of phytoplankton in the ocean could dramatically alter hurricane frequency.

In an upcoming issue of the journal Geophysical Research Letters, NOAA researcher Anand Gnanadesikan and colleagues demonstrate that the formation of North Pacific typhoons is heavily mediated by the presence of chlorophyll, the green pigment that helps the tiny single-celled organisms convert sunlight into energy. Using computer modeling, Gnanadesikan and colleagues established that a decrease in phytoplankton, and thus in chlorophyll, in the North Pacific gyre, where typhoons form, led to a decrease in the number of hurricane-force storms.

In the absence of chlorophyll, sunlight is able to penetrate deeper into the ocean, leaving the surface water cooler. Cold water provides less energy, leading to changes in air circulation patterns. This results in drying air and stronger winds, which tend to prevent thunderstorms from developing the necessary superstructure that allows them to grow into hurricanes.

Although the study involved model simulations of phytoplankton loss, and although a complete absence of chlorophyll is improbable, Gnanadesikan noted in a press release to announce the paper's findings that a recent study (featured in the August 10, 2010, issue of Ocean Update) found that phytoplankton had been decreasing steadily over the past century.

Source: Gnanadesikan, A., et al. In Press. How ocean color can steer tropical Pacific cyclones. Geophysical Research Letters.

Contact: Anand Gnanadesikan, NOAA. E-mail: anand.gnanadesikan@noaa.gov.

Ice-Free Arctic Ocean May Not Be Carbon Sink

Declines in the Arctic Ocean sea ice have caused researchers to speculate that the region may become a "sink" for carbon dioxide, a hypothesis disputed by a new study. National Snow and Ice Data Center

Since the Industrial Revolution, approximately 30 percent of the increase in atmospheric carbon dioxide has been taken up by the ocean. Because of the Arctic Ocean's low temperatures and high levels of biological activity, this body of water accounts for a high proportion of the atmospheric carbon dioxide entering ocean waters. A recent synthesis suggested that, despite accounting for just 3 percent of total ocean area and being mostly ice-covered, it accounts for up to 14 percent of total ocean uptake.

Many researchers have predicted that, as sea ice melts due to warming, the Arctic Ocean will become an even more substantial "sink" for atmospheric carbon dioxide. However, a recent study in the journal Science casts doubt on that theory.

Wei-Jun Cai of the University of Georgia and colleagues studied levels of carbon dioxide concentration in Arctic waters of the Canada Basin, where substantial sea ice melting had occurred. They found that levels had increased substantially compared to earlier studies in 1999; however, they also observed a number of factors that appeared to limit continued rapid carbon dioxide uptake.

For one thing, carbon dioxide levels in the water increased so rapidly that they soon approached equilibrium with the atmosphere, greatly reducing its ability to absorb any more. At the same time, although photosynthesizing phytoplankton flourished in areas of diminished sea ice cover (presumably as a result of increased sunlight), they actually decreased in areas that were completely sea-ice free. Cai and his co-authors postulate that this is because nutrient supply is reduced in those conditions as a result of melting snow and ice on land resulting in an increase in freshwater. Such increased freshwater input prevents the layers of seawater from mixing as they would under normal circumstances, limiting the supply of nutrients and thus causing a reduction in phytoplankton that would otherwise utilize carbon dioxide for photosynthesis.

In a press release to announce the findings, Cai concluded that, "One of the take-away lessons of this research is that we can't expect the oceans to do the job of helping offset global warming in the short term."

Source: Cai, W-J., et al. 2010. Decrease in the CO2 uptake capacity in an ice-free Arctic Ocean. Science 329: 556-559.

Contact: Wei-Jun Cai, University of Georgia. E-mail: wcai@uga.edu

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