Showing posts with label Woods Hole Oceanographic Institution. Show all posts
Showing posts with label Woods Hole Oceanographic Institution. Show all posts

Wednesday, February 26, 2014

Fukushima radioactive plume due to reach West Coast this spring. One Model predicts a maximum concentration of 27 becquerels per cubic metre of water on the Canadian coast by mid-2015


Scientists say lack of government supported research forcing them to use volunteers, predictive models

- Lauren McCauley, staff writer

An image from a model of the progression of a radioactive plume coming across the Pacific following the Fukushima nuclear meltdown. (via BBC News)A radioactive plume released from the Fukushima meltdown is expected to reach the west coast of the U.S. in April, said a panel of researchers in Honolulu Monday. However, without any federal or international monitoring, scientists are bereft of "actual data," guessing at the amount of radiation coming at us.
Monitors along the Pacific U.S. coast have yet to detect any traces of cesium-134, said Ken Buesseler, a chemical oceanographer at the Woods Hole Oceanographic Institution (WHOI), speaking on a panel at the meeting of the American Geophysical Union's Ocean Sciences. However, sampling undertaken by Dr. John Smith at the Bedford Institute of Oceanography has helped develop models that forecast the "probable future progression of the plume."
According to Buesseler, initial traces should be detectable along the Pacific coast in April.
One of the radioactive isotopes that is formed during a nuclear accident is cesium-134. With a short half-life of two years, any traces of it detected by monitoring instruments can be specifically attributed to the Fukushima nuclear accident.
Another isotope, cesium-137, decays very slowly with a half-life of 30 years. Though traces of cesium-137 have been detected in the world's oceans, their source may be attributed to previous nuclear-weapons tests.
One shortcoming of the current models available to the scientists is that lack of solid data is creating varying predictions about the amount of radiation and when it is expected to reach the west coast. And though the estimated levels fall far shorter than acceptable drinking water concentrations, according to the WHOI, the concern is not direct exposure but rather the "uptake by the food web and, hence, the potential for human consumption of contaminated fish."
"To my mind, this is not really acceptable," said Buesseler, speaking of the variation between the predictive models. "We need better studies and resources to do a better job, because there are many reactors on coasts and rivers and if we can’t predict within a factor of 10 what cesium or some other isotope is downstream—I think that’s a pretty poor job."
Individuals have recently spread alarm about the presence of radioactive isotopes already found along the Pacific coast, although those concerns were debunked.
Without any federal or international agencies currently monitoring ocean waters from Fukushima on this side of the Pacific, Buesseler and the WHOI have had to recruit volunteers to collect seawater at 16 sites along the California and Washington coasts and two in Hawaii and ship the samples back to the Cape Cod, Mass. laboratory.
"We need to know the real levels of radiation coming at us," said Bing Dong, a retired accountant and one of the volunteers with the WHOI project. "There's so much disinformation out there, and we really need actual data."
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Radioactive water travelling from Fukushima power plant being measured by scientists


Researchers are attempting to predict the amount of radioactive water from Japan that will hit the North American coast.

The concentration of radioactive water from the Fukushima power plant in Japan expected to hit North American coasts should be known in the next two months.
So far only small traces of pollution have been recorded in Canadian continental waters, but this is expected to increase as contaminants move eastwards on Pacific currents, BBC News has reported.
In 2011, three nuclear reactors at the Japanese facility went into meltdown, leaking radiation into the Pacific Ocean.
Researchers from the Bedford Institute of Oceanography in Canada have been analysing water along a line running almost 2,000km due west of Vancouver, British Columbia, since the 2011 Fukushima accident.
In June 2013, radioactive caesium-137 and 134 were detected in the entire line of the sampling length.
Scientists stress that even with the probable increases taken into account, the measurements will be well within limits set by safety authorities.
Researchers have harnessed the radioactive water to test two forecasting models to try and map the probable future progression of the plume of radioactive water.
Using one model, the scientists have predicted that a maximum concentration of 27 becquerels per cubic metre of water will appear on the Canadian coast by mid-2015, but the other model predicts no more than about two becquerels per cubic metre of water.
Bedford’s Dr John Smith told BBC News that further measurements currently being taken in the ocean should give researchers a fair idea of which model is correct.
Read More Here


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Tuesday, October 29, 2013

Toxic Ocean Conditions During Mass Extinction Reveals Insight into Today's Climate


First Posted: Oct 29, 2013 10:56 AM EDT
Ocean
It turns out that it doesn't take much to turn our planet's ocean waters into something that's toxic to life. Scientists have taken a closer look at a massive extinction event that occurred 93.9 million years ago and have found that it didn't take as much sulfide as previously thought in the ocean waters to cause this major climatic perturbation. (Photo : Flickr.com/Jim Epter)
It turns out that it doesn't take much to turn our planet's ocean waters into something that's toxic to life. Scientists have taken a closer look at a massive extinction event that occurred 93.9 million years ago and have found that it didn't take as much sulfide as previously thought in the ocean waters to cause this major climatic perturbation.
In order to examine this particular extinction, the scientists examined the chemistry of rocks deposited during that time period. This revealed that oxygen-free and hydrogen sulfide-rich waters extended across roughly five percent of the global ocean. That's far more than today modern ocean's at .1 percent, but far less than previously thought.
"These conditions must have impacted nutrient availability in the ocean and ultimately the spatial and temporal distribution of marine life," said Jeremy Owens, one of the researchers, in a news release. "Under low-oxygen environments, many biologically important metals and other nutrients are removed from seawater and deposited in the sediments on the seafloor, making them less available for life to flourish."

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The Daily Galaxy

EcoAlert --Toxic Hydrogen Sulfide-Rich Oceans Led to Major Extinction 93.9 Million Years Ago


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“Today, we are facing rising carbon dioxide contents in the atmosphere through human activities, and the amount of oxygen in the ocean may drop correspondingly in the face of rising seawater temperatures,” said said Timothy W. Lyons, a professor of biogeochemistry at University of California (Riverside). “Oxygen is less soluble in warmer water, and there are already suggestions of such decreases. In the face of these concerns, our findings from the warm, oxygen-poor ancient ocean may be a warning shot about yet another possible perturbation to marine ecology in the future.”
Oxygen in the atmosphere and ocean rose dramatically about 600 million years ago, coinciding with the first proliferation of animal life. Since then, numerous short-lived biotic events — typically marked by significant climatic perturbations — took place when oxygen concentrations in the ocean dipped episodically. The most studied and extensive of these events occurred 93.9 million years ago. By looking at the chemistry of rocks deposited during that time period, specifically coupled carbon and sulfur isotope data, a research team led by UCR biogeochemists reports that oxygen-free and hydrogen sulfide-rich waters extended across roughly five percent of the global ocean during this major climatic perturbation — far more than the modern ocean’s 0.1 percent but much less than previous estimates for this event.
The research suggests that previous estimates of oxygen-free and hydrogen sulfide-rich conditions, or “euxinia,” were too high. Nevertheless, the limited and localized euxinia were still sufficiently widespread to have dramatic effect on the entire ocean’s chemistry and thus biological activity.

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