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Special Fukushima Session At 2012 Ocean Sciences Meeting

February 16, 2012

The March 11, 2011, earthquake, tsunami, and subsequent radioactivity releases from the Fukushima Dai-ichi nuclear power plants resulted in the largest accidental release of radiation to the ocean in history.

In a special session on Tuesday, Feb. 21, during the 2012 Ocean Sciences Meeting in Salt Lake City, researchers will present early results from several field and modeling studies examining the fate of more than a dozen radioactive isotopes in the air, water, and organisms impacted by the Fukushima releases. This is the largest international gathering to date of experts in this area. The session will feature 15 talks, including two by Woods Hole Oceanographic Institution (WHOI) scientists.

WHOI talks in the session:

WHOI marine chemist Ken Buesseler led a group of scientists from the U.S., Japan, and Europe on a June 2011 research cruise to study Fukushima-derived radionuclides in the waters off Japan. During the two-week cruise, 17 researchers and technicians collected more than 3,000 liters of water samples for analysis.

Buesseler’s talk will focus on cesium-137 and cesium-134 surface distributions and vertical profiles that were obtained during the June 2011 cruise. The highest cesium concentrations found in the waters at that time were 70-100 kilometers off shore, rather than at the closest sampling point, which was 30 km from the Fukushima Nuclear Power Plant. Buesseler said the data suggests that the Kuroshio Current–a strong, western boundary current comparable to the Gulf Stream in the Atlantic Ocean–prevented contaminated water from spreading southward. Fukushima-derived cesium was found out to at least 600 km off shore. While cesium isotopes are elevated 10-1000 times over prior levels, radiation risks for waters >30 km off Japan are below those generally considered harmful to marine animals and human consumers, though continued releases from the nuclear power plant and accumulation of contaminants in sediments may be of long-term concern.

Presentation Title: Impacts of the Fukushima Dai-Ichi Nuclear Power Plants on the Ocean
Date: Tuesday, Feb. 21
Time: 11:30 a.m.
Location: Ballroom E

WHOI physical oceanographer Steven Jayne will report on what researchers learned from 24 surface drifters that were deployed and tracked in the waters off the eastern coast of Japan. The trajectories of these drifters indicate that much of the contaminated water was being pulled away from the coast on the northern side of the Kuroshio Extension. A few of the drifters stayed in the coastal region, suggesting that some of the contaminated water may actually recirculate in this area before being washed offshore. The absence of drifter crossings across the Kuroshio Extension core suggests that it inhibits the southward spreading of contaminated water, at least over the western Pacific Ocean. The drifter trajectories can be used to extend the tracking back to the initial releases and into the future to track the fate of the contamination, Jayne said.

Presentation Title: Tracing the Circulation Around Fukushima
Date: Tuesday, Feb. 21
Time: 11:45 a.m.
Location: Ballroom E

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