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Oceans: Drake Passage seen as mixing ground

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Strong storms help push water through the Drake Passage, and beneath the surface, the surging currents help mix the ocean from top to bottom. bberwyn photo.

Underwater mountains help churn up the ocean, fueling the carbon cycle

By Summit Voice

FRISCO — The Drake Passage, between the tip of South America and the Antarctic Peninsula, is well known for wild storms and big swell, but it turns out that turbulence isn’t just at the surface.

Far beneath the breaking whitecaps, the area is a crucial ocean mixing ground, where surface water is exchanged with deep water as currents rush over undersea mountains. Those mixing of water layers are crucial to regulating the Earth’s climate and ocean currents, according to researchers who recently traced how that mixing happens. Continue reading

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Environment: Researchers still tracking oil leaks from the Deepwater Horizon disaster in the Gulf of Mexico

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A massive slick from the Deepwater Horizon oil spill spreads across the Gulf of Mexico in July 2010. Photo courtesy NASA.

Oil ‘fingerprinting’ technique shows the oil is likely from the wreckage of the sunken drill rig

By Summit Voice

FRISCO — Chemical fingerprints show that oil sheens in the Gulf of Mexico are probably from pockets of oil trapped within the wreckage of the sunken Deepwater Horizon drilling rig. Both the Macondo well and natural oil seeps common to the Gulf of Mexico were confidently ruled out by researchers from Woods Hole Oceanographic Institution and the University of California, Santa Barbara. The study was published online this week in Environmental Science & Technology.

The oil sheens were first reported to the United States Coast Guard by BP in mid-September 2012, raising public concern that the Macondo well, which was capped in July 2010, might be leaking.

“It was important to determine where the oil was coming from because of the environmental and legal concerns around these sheens. First, the public needed to be certain the leak was not coming from the Macondo well, but beyond that we needed to know the source of these sheens and how much oil is supplying them so we could define the magnitude of the problem,” said WHOI chemist Chris Reddy. Continue reading

Environment: New research documents vast new microbial communities taking shape in swirling ocean garbage patches

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A NOAA map shows where huge quantities of human garbage are ending up in a central Pacific Ocean convergence zone.

Wider impacts of ‘plastisphere‘ still unknown, but marine debris could serve as vector for harmful bacteria

By Summit Voice

FRISCO — The infamous ocean garbage patches, where  our refuse ends up swirling around in great ocean gyres, have become “microbial reefs” of sorts, where untold multitudes of organisms have found a new home.

Scientists have dubbed this extensive new habitat the “plastisphere,” where they say more research is needed to determine if there are any impacts to wider ocean ecosystems.

Some of the questions include: How will it change environmental conditions for marine microbes, favoring some that compete with others? How will it change the overall ocean ecosystem and affect larger organisms? How will it change where microbes, including pathogens, will be transported in the ocean? Continue reading

Climate: Study shows possible pitfalls of ‘seeding’ oceans

Stimulating phytoplankton could backfire

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By Summit Voice
One of the ideas that has surfaced most often is adding certain types of nutrients to the oceans to stimulate algae production in the hopes of reducing CO2. But new research shows that the law of unintended consequences always applies, perhaps even more so when experimenting with climate on a global scale.

The new study on the feeding habits of ocean microbes shows that the idea could backfire by disturbing the natural balance of ocean chemistry. After carefully studying diatoms, one type of plankton, the scientists determined that it is uses more iron that it needs for photosynthesis and storing the extra in its silica skeletons and shells. This reduces the amount of iron left over to support the carbon-eating plankton.

“Just like someone walking through a buffet line who takes the last two pieces of cake, even though they know they’ll only eat one, they’re hogging the food,” said Ellery Ingall, a professor at the Georgia Institute of Technology and co-lead author on this result.  “Everyone else in line gets nothing; the person’s decision affects these other people.” Continue reading

Fukushima ocean radiation panel to be live-streamed

Experts to discuss concerns about radioactive dispersion; viewers can ask questions via Twitter during May 9 session

FRISCO — More than two years have passed since a 9.0 earthquake and a 50-foot tsunami catastrophically damaged the Fukushima Dai-ichi nuclear power plant on Japan’s northeast coast, but questions still linger about the long-term impacts of radioactive pollution in the ocean.

The quake and tsunami killed about 20,000 people, and some coastal Japanese fisheries are still closed due to concern about the radiation. Next week, an international panel of scientists will discuss the accident and potential impacts to the environment and human health in a web-streamed session at the Woods Hole Oceanographic Institution.

The panel will be held on May 9, 2013, from 6:30 to 9:30 p.m. EDT and simulcast on the Web (http://www.whoi.edu/fukushima). Online viewers are encouraged to participate and send questions for the panel discussion via Twitter. The event hashtag is #WHOIfukushima. Questions during the discussion can also be sent via email to cmer@whoi.edu. Continue reading

Greenland runoff may be a big source of iron

Runoff from melting Greenland glaciers may be a significant source of iron in the North Atlantic.

Runoff from melting Greenland glaciers may be a significant source of iron in the North Atlantic. Bob Berwyn photo.

Arctic meltdown may have consequences besides raising sea level

By Summit Voice

FRISCO — Melting Greenland glaciers may have an unforeseen side effect on ocean biology, as the surging runoff adds iron to the water, potentially fueling more plankton growth.

Glaciers have just recently been identified as a significant source of iron in a study by biogeochemists and glaciologists at Woods Hole Oceanographic Institution. The findings suggest that the influx of iron could increase as melting of the Greenland ice sheet escalates under a warming climate.

It’s long been known wind-blown dust and river runoff are source of iron, but meltwater runoff from glaciers and ice sheets was considered too dilute to carry much iron, although previous research has shown a strong correlation between the plankton blooms and the runoff from Greenland ice sheet. Continue reading

Climate: Study eyes regional patterns of ocean acidification

Gulf of Mexico appears more resistant to acidification threats

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The impacts of ocean acidification will vary from region to region. Bob Berwyn photo.

By Summit Voice

SUMMIT COUNTY — A 2007 sea voyage through the Gulf of Mexico, around Florida and up the eastern seaboard has increased understanding of how various coastal areas may respond to increased acidity. More than anything, the detailed research helps establish some baseline data against which future changes can be measured, and showed that some areas are more susceptible to higher concentrations of carbon.

The study, measuring levels of carbon dioxide and other forms of carbon in the ocean, was conducted by scientists from 11 institutions across the U.S. and was published in the journal Limnology and Oceanography.

“Before now, we haven’t had a very clear picture of acidification status on the east coast of the U.S.,” says Zhaohui ‘Aleck’ Wang, the study’s lead author and a chemical oceanographer at Woods Hole Oceanographic Institution. “It’s important that we start to understand it, because increase in ocean acidity could deeply affect marine life along the coast and has important implications for people who rely on aquaculture and fisheries both commercially and recreationally.” Continue reading

Study shows ocean acidification impacts to sea snails

Corrosive waters in Southern Ocean destroying pteropod shells

Pteropods swimming in the Scotia Sea. Photo courtesy British Antarctic Survey.

By Bob Berwyn

FRISCO — Numerous lab experiments have already shown that some shell-forming ocean species will likely suffer as the ocean absorbs atmospheric carbon dioxide and becomes increasingly acidic.

Now, a new study based on 2008 research in the Scotia Sea shows that the shells of tiny marine snails called pteropods are already being dissolved by ocean acidification where atmospheric CO2 being absorbed by the sea is exacerbating acidic conditions resulting from upwelling of cold water from deep below the surface.

The tiny animals are a valuable food source for fish and birds and play an important role in the oceanic carbon cycle. Pteropods are open-ocean animals, moving about by using water wings that evolved from their snail feet. Continue reading

Global warming: Ice loss threatens emperor penguins

Emperor penguin and chick. PHOTO COURTESY BRITISH ANTARCTIC SURVEY.

By Bob Berwyn

SUMMIT COUNTY — Not long after biologists with the British Antarctic Survey documented the disappearance of an emperor penguin colony, a new research effort also suggests that climate change may drastically reduce Antarctic habitat for the iconic ice-dwelling birds.

Focusing on a long-studied colony in Terre Adélie, scientists with the Woods Hole Oceanographic Institution concluded that the number of breeding pairs at the colony could drop by 80 percent by the end of the century.

“The projected decreases in sea ice may fundamentally alter the Antarctic environment in ways that threaten this population of penguins,” said NCAR scientist Marika Holland, a co-author of the study.

Another recent study by the British Antarctic Survey suggested that emperor penguin populations are much higher, perhaps twice as large, as previously believed. Last November, conservation groups petitioned the U.S. Fish and Wildlife Service to list emperor penguins under the Endangered Species Act. Continue reading

Indus civilization collapse linked with climate change

Shifting monsoons seen as key factor in Harappan decline

The Lower Indus River near Karachi. IMAGE COURTESY NASA.

By Summit Voice

SUMMIT COUNTY — In what could be a warning sign for modern civilizations that sustain themselves with complex water diversion schemes, a new study of the Indus River Basin suggests that climate change led to the collapse Harappan Civilization almost 4000 years ago.

The Indus civilization was the largest —but least known — of the first great urban cultures that also included Egypt and Mesopotamia. At its height, the culture spread across about 600,000 square miles in what is now Pakistan, northwest India and eastern Afghanistan.

Like their contemporaries, the Harappans, named for one of their largest cities, lived next to rivers owing their livelihoods to the fertility of annually watered lands.

The new study suggests declining monsoons reduced the river flows and associated floodplain development that helped fuel the development of the Harappan culture by nurturing agricultural surpluses used to build wealth. Continue reading

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