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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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Global warming: Moss bank core samples from Antarctic Peninsula offer new climate clues

‘Unprecendented rate of ecological change’

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A careful study of moss banks on the Antarctic Peninsula has given researchers a new way to measure global warming impacts. bberwyn photo.

By Summit Voice

FRISCO — Finding ways to assess the impacts of global warming in Antarctica isn’t always easy. Measurements of ice help show some of the changes but don’t tell the whole story, so British researchers took a close look at a 150-year-old moss bank on the Antarctic Peninsula, one of the fastest-warming regions on Earth.

The analysis shows an unprecedented rate of ecological change since the 1960s driven by warming temperatures, according to the findings published Aug. 29 in Current Biology. Temperatures on the Antarctic Peninsula have increased by up to 0.56 degrees Celsuis per decade since the 1950s. Continue reading

Climate: Study paints nuanced picture of regional and global temperature variability in a warming world

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Australia experienced a record-breaking summer heatwave this year.

Loss of sea ice will eventually lead to decrease in global temperature variability

By Summit Voice

FRISCO — Climate scientists from the UK say their latest study paints a nuanced picture of global temperature variability, outlining recent geographical shifts and projecting an overall long-term decrease in variability as global temperatures rise.

“Fluctuations in annual average temperatures have shown very substantial geographical alteration in recent decades. However, to our surprise, when considered across the globe, total variability has been relatively stable,” said
lead author Dr. Chris Huntingford, with the Centre for Ecology & Hydrology (a joint program of the University of East Anglia and the University of Exeter).

Yearly temperature variability has increased across large parts of Europe and North America in recent decades, but has decreased or remained stable in other regions, according to the study published July 24 in Nature. Continue reading

Coral reefs: ‘Business as usual won’t cut it’

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Coral reef ecosystems are facing serious threats from global warming as well as local impacts. Photo courtesy Renata Ferrari.

Study says concerted global and local action required

By Summit Voice

SUMMIT COUNTY — A detailed new study supports the idea that protecting coral reefs from local impacts like over-fishing and polluted runoff is a key part of any strategy to try and bolster reefs in the face of climate change.

The researchers concluded that, even though coral reefs are in decline, their collapse can be avoided with concerted global and local action.

“People benefit by reefs’ having a complex structure—a little like a Manhattan skyline, but underwater,” said Peter Mumby, of The University of Queensland and University of Exeter. “Structurally complex reefs provide nooks and crannies for thousands of species and provide the habitat needed to sustain productive reef fisheries. They’re also great fun to visit as a snorkeler or diver. If we carry on the way we have been, the ability of reefs to provide benefits to people will seriously decline.” Continue reading

Cold-weather lizards facing climate crunch

Dozens of species could be doomed to extinction

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Climate change is likely to drive dozens of lizard species to extinction. Photo courtesy USFWS.

By Summit Voice

FRISCO — Lizards that give birth to live young may be headed for a climatic cul-de-sac in the next 50 years, according to a new study by scientists with the University of Exeter and the University of Lincoln.

“Climate change must not be underestimated as a threat to modern patterns of biodiversity,” said University of Exeter biologist Dr. Dave Hodgson. “Our work shows that lizard species which birth live young instead of laying eggs are restricted to cold climates in South America …  high in the Andes or towards the South Pole. As the climate warms, we predict that these special lizard species will be forced to move upwards and towards the pole, with an increased risk of extinction.”

The viviparous lizards — one of the most diverse groups of vertebrates on earth — have been able to adapt to cooler ecological niches, but their evolutionary adaptation means they remain restricted to cold climates. Continue reading

Coral reef research highlights big drop in growth rates

Caribbean corals struggling to produce enough calcium carbonate to survice

A coral reef at the Palmyra Atoll National Wildlife Refuge. Photo courtesy Jim Maragos/USFWS.

A coral reef at the Palmyra Atoll National Wildlife Refuge. Photo courtesy Jim Maragos/USFWS.

By Summit Voice

SUMMIT COUNTY — Many coral reefs in the Caribbean are struggling to keep pace with erosion, as their ability to produce and accumulate calcium carbonate declines in the face of human-caused impacts, researchers from the University of Exeter reported this week. That inability to grow raises serious questions about whether the reefs will be able to adapt to rising sea levels, the researchers reported.

Coral reefs are important ocean biodiversity hotspots and serve as nurseries for a profusion of marine life. In a sweeping decision several weeks ago, federal biologists said at least 66 species of coral in the Caribbean and Pacific are in danger of going extinct because of threats linked to global warming caused by greenhouse gas emissions.

Coral cover on reefs in the Caribbean has declined by an average of 80 percent since the 1970s, driven mainly by human disturbance, disease and rising sea temperatures, and are only expected to intensify as a result of future climate change. Continue reading

Global warming: New Arctic forests could spur net carbon gain

The role of forests in the cycle of global warming and carbon is critical.

New study suggests tundra conversion to forest could increase atmospheric CO2 levels

By Summit Voice

SUMMIT COUNTY — While some climate research suggests that warming temperatures could lead to faster tree growth, and thus, more carbon capture, new research from the University of Exeter concludes that new forests growing in the Arctic could result in a net gain of carbon dioxide in the atmosphere.

That’s because those new forests will free up carbon previously held frozen in the tundra and release it as part of their growth cycle, the researcher said. Those emissions could outweigh increased carbon sequestration by forests in other parts of the world.

As a basis for their research, the scientists acknowleged that the Arctic is getting greener as plant growth increases in response to a warmer climate. The new study, published in Nature Climate Change, shows that, by stimulating decomposition rates in soils, the expansion of forest into tundra in arctic Sweden could result in the release of carbon dioxide to the atmosphere. Continue reading

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