Tag Archives: sea ice

Cassini Suggests Icing on a Lake

It’s not exactly icing on a cake, but it could be icing on a lake. A new paper by scientists on NASA’s Cassini mission finds that blocks of hydrocarbon ice might decorate the surface of existing lakes and seas of liquid hydrocarbon on Saturn’s moon Titan. The presence of ice floes might explain some of the mixed readings Cassini has seen in the reflectivity of the surfaces of lakes on Titan.

“One of the most intriguing questions about these lakes and seas is whether they might host an exotic form of life,” said Jonathan Lunine, a paper co-author and Cassini interdisciplinary Titan scientist at Cornell University, Ithaca, N.Y. “And the formation of floating hydrocarbon ice will provide an opportunity for interesting chemistry along the boundary between liquid and solid, a boundary that may have been important in the origin of terrestrial life.” (more…)

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USGS Study Tracks Pacific Walrus, Observes Effects of Arctic Sea Ice Loss on Behavior

ANCHORAGE, Alaska — Sparse summer sea ice in the Arctic over the past five years has caused behavioral changes in Pacific walruses according to research published by U.S. Geological Survey and Russian scientists. The effects on the walrus population are unknown.

“The loss of sea ice is the ‘why’ for the change in walrus behavior; the tracking data tells us the ‘where’ in terms of their new forage patterns,” said USGS Director Marcia McNutt. “What awaits to be seen is ‘how much will it matter?'” (more…)

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Scientists Uncover Vast Differences in Earth’s Polar Ocean Microbial Communities

ANN ARBOR— An international team of scientists, including a University of Michigan graduate student, has demonstrated that a clear difference exists between the marine microbial communities in the Southern and Arctic oceans, contributing to a better understanding of the biodiversity of marine life at the poles.

The most comprehensive comparison of microbial diversity at both of Earth’s polar oceans showed that about 75 percent of the organisms at each pole are different. This insight sheds light on newly recognized biodiversity patterns and reinforces the importance of studying Earth’s polar regions in the face of a changing climate. And it highlights the need for further research on the impacts of sea ice, seasonal shifts and freshwater input in both regions. (more…)

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Shrinking Snow Depth on Arctic Sea Ice Threatens Ringed Seal Habitat

As sea ice in the Arctic continues to shrink during this century, more than two thirds of the area with sufficient snow cover for ringed seals to reproduce also will disappear, challenging their survival, scientists report in a new study.

The ringed seal, currently under consideration for threatened species listing, builds caves to rear its young in snow drifts on sea ice. Snow depths must be on average at least 20 centimeters, or 8 inches, to enable drifts deep enough to support the caves. (more…)

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Surviving Without Ice

Arctic crustaceans use currents, deep-water migration to survive sea ice melts

With sea ice in the Arctic melting to record lows in summer months, marine animals living there face dramatic changes to their environment. Yet some crustaceans, previously thought to spend their entire lives on the underside of sea ice, were recently discovered to migrate deep underwater and follow ocean currents back to colder areas when ice disappears.

“Our findings provide a basic new understanding of the adaptations and biology of the ice-associated organisms within the Arctic Ocean,” said Mark Moline, director of the University of Delaware’s School of Marine Science and Policy in the College of Earth, Ocean, and Environment. “They also may ultimately change the perception of ice fauna as imminently threatened by the predicted disappearance of perennial sea ice.” (more…)

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On The Front Lines

UD scientist sees Arctic ice loss firsthand

The extent of sea ice in the Arctic has reached a record low, according to data released Aug. 26 by the U.S. National Snow and Ice Data Center (NSIDC).

A University of Delaware marine scientist can confirm some of that ice loss firsthand. In a short video he produced, Andreas Muenchow, aboard the Canadian icebreaker Henry Larsen, shows the ice-free sea off Petermann Fjord that he and his colleagues were sailing in — an area that for ages had been covered by floating ice shelves. (more…)

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Heather Leslie: Measuring ocean health

Sustainable management of a huge, complex and valuable resource such as the ocean requires a comprehensive metric that did not exist until now. In the Aug. 16 edition of Nature a broad group of scientists including Heather Leslie, the Sharpe Assistant Professor of Environmental Studies, describes the Ocean Health Index. The index rates coastal places, from regions to nations, on 10 goals: artisanal fishing opportunity, biodiversity, carbon storage, clean waters, coastal livelihoods and economies, coastal protection, food provision, natural products, sense of place, and tourism and recreation. Leslie recently answered questions posed by David Orenstein.

How does the Ocean Health Index’s focus on integrating human factors make it different and valuable?

Recognizing people’s integral roles in ocean ecosystems, this index evaluates how well the ocean provides 10 key benefits to people and how well we are protecting its ability to do so in the future. (more…)

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Scientists Discover Huge Phytoplankton Bloom in Ice Covered Waters

A team of researchers, including scientists from Woods Hole Oceanographic Institution (WHOI), discovered a massive bloom of phytoplankton beneath ice-covered Arctic waters. Until now, sea ice was thought to block sunlight and limit the growth of microscopic marine plants living under the ice.

The amount of phytoplankton growing in this under-ice bloom was four times greater than the amount found in neighboring ice-free waters. The bloom extended laterally more than 100 kilometers (62 miles) underneath the ice pack, where ocean and ice physics combined to create a phenomenon that scientists had never seen before. (more…)

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