About these ads

Climate: Icebergs scouring biodiversity from sea-bottom boulders around the Antarctic Peninsula

‘The Antarctic Peninsula can be considered an early warning system … ‘

gh

Icebergs near the shore of the Antarctic Peninsula are scouring the sea-bottom of its biodiversity, according to researchers with the British Antarctic Survey. bberwyn photo.

Staff Report

FRISCO — Antarctic icebergs set free to roam near the shore by global warming are fundamentally changing the seafloor ecology, according to researchers with the British Antarctic Survey.

Boulders on the shallow seabed — once encrusted with a rich assemblage of species in intense competition for limited space — now mostly support a single species. The climate-linked increase in iceberg activity has left all other species so rare as to be almost irrelevant, according to the new study published in the Cell Press journal Current Biology on June 16.

“The Antarctic Peninsula can be considered an early warning system—like a canary in a coal mine,” says David Barnes of the British Antarctic Survey. “Physical changes there are amongst the most extreme and the biology considered quite sensitive, so it was always likely to be a good place to observe impacts of climate change—but impacts elsewhere are likely to be not too far behind. A lot of the planet depends on the near-shore environment, not least for food; what happens there to make it less stable is important.” Continue reading

About these ads

‘Heatwave’ at South Pole sets records

More record-warm Antarctica temperatures recorded in September

Global weirding? Antarctic sea ice hits record highs and South Pole sees record high temps. bberwyn photo.

Global weirding? Antarctic sea ice hits record highs and South Pole sees record high temps. bberwyn photo.

By Summit Voice

FRISCO — While scientists recently pinpointed areas with all-time record low temperatures in Antarctica, the South Pole is not immune to global warming — scientists based at the bottom of the world say the past winter was the warmest since record-keeping started in 1957.

In August, for example, the average temperature for the month was more than 11 degrees Fahrenheit above average, at minus 63.9 degrees Fahrenheit.

The trend continued into the Austral spring, with September 2013 also ending up as an all-time record warm month, including four daily maximum temperature records, according to the Antarctic Sun.

That’s not to say the weather was balmy — the average annual temperature at the South Pole is about minus 56.9 degrees Fahrenheit. The coldest reading on record was minus 117 degrees Fahrenheit, set June 23, 1982, while the warmest temperature recorded since 1957 was just a few years ago, Christmas Day, 2011, when the official high was 9.9 degrees Fahrenheit. Continue reading

Oceans: Drake Passage seen as mixing ground

f

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

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

‘Unprecendented rate of ecological change’

sdfg

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

Antarctic clams may take a hit from global warming

Study shows climate change may affect overall population numbers

dfgh

Changes in Antarctic clam populations could have a ripple effect on other species in the region like these blue-eyed cormorants in the South Shetlands. Bob Berwyn photo.

By Summit Voice

FRISCO — Warming ocean temperatures and increased glacial outflow around Antarctica may have a big impact on clams living on the ocean floor. Younger clams try to move away when they sense warmer temperature or reduced oxygen levels, but older clams stay put.

The findings by a team of British and German scientists indicate how climate change may affect biodiversity in the region, suggesting that the overall population of Antarctic clams may dwindle, since it’s the older animals that reproduce.

“Our study shows that the physiological flexibility of young clams diminishes as they get older. However, the species has evolved in such a way that the fittest animals, that can tolerate life in an extreme environment, survive to reproduce into old age,” said Doris Abele, of the Alfred Wegener Institute in Germany. “Climatic change, affecting primarily the older clams, may interfere with this evolutionary strategy, with unpredictable consequences for ecosystems all around Antarctica.” Continue reading

Climate: Antarctica surface melting speeds up

Ice core study shows rapid pace of change along Antarctic Peninsula

dfgj

Warmer summer temperatures along the Antarctic Peninsula are starting to take a toll on ice and snow in the region. Bob Berwyn photo. (Dundee Island).

By Bob Berwyn

FRISCO — Careful study of a 1,200-foot long ice core sample spanning 1,000 years suggests that summer ice melt in parts of the Antarctic Peninsula region has intensified almost tenfold. About 5 percent of the annual snowfall has been melting in recent years, compared with only about 0.5 percent during the coolest phase (about 600 years ago) of that 1,000-year span.

“This is the first time it has been demonstrated that levels of ice melt on the Antarctic Peninsula have been particularly sensitive to increasing temperature during the 20th Century,” said Dr. Nerilie Abram, a climate researcher at Australian National University who studied the ice core from James Ross Island.

Most of the increased melting occurred during the past half-century, corresponding with the era of increasing greenhouse gas emissions and a remarkable warmup around the peninsula and some other parts of Antarctica. Borehole temperature estimates from the West Antarctic Ice Sheet also indicate rapid acceleration of West Antarctic warming during the past two decades. Continue reading

Morning Photo: Antarctic Peninsula

Researchers confirm dramatic meltdown

Dawn in the Antarctic Sound.

Dawn in the Antarctic Sound.

FRISCO — A new study once again confirms the rapid warmup of the Antarctic Peninsula, due to shifting wind patterns. The increased temperatures are manifesting in a longer melt season, with potentially huge consequences for ecoystems and physical features, including coastal ice shelves, which are already cracking and crumbling. There have already been big shifts in penguin populations, and krill, at the base of the Southern Ocean food web, is also at risk. Read the story to learn more, check out more Summit Voice coverage of Antarctica here.

sdfg

A lone chinstrap penguin on an iceberg in the Antarctic Sound.

Continue reading

Antarctic Peninsula’s melt season lengthens dramatically

Warmer temps linked with ice shelf break-ups

sdfg

A longer melt season along the Antarctic Peninsula has consequences for wildlife — and for the long-term fate of the coastal ice shelves. Bob Berwyn photo.

By Summit Voice

SUMMIT COUNTY — The melt season on the Antarctic Peninsula is growing longer — in some cases it has doubled, and several major ice shelf breakup events in the region coincided with longer than usual melt seasons, according to a a new study that analyzed data from 30 weather stations.

“We found a significant increase in the length of the melting season at most of the stations with the longest temperature records,” said Dr. Nick Barrand, who carried out the research while working for the British Antarctic Survey. “At one station the average length of the melt season almost doubled between 1948 and 2011,” said Barrand, who now works for the University of Birmingham. Continue reading

Study finds link between El Niño and warming along the Antarctic Peninsula during parts of the Holocene

Ocean-driven warming along western Antarctic Peninsula may be partly driven by natural climate variability

dg

Ice remnants along the shore of the Antarctic Peninsula. Bob Berwyn photo.

By Summit Voice

SUMMIT COUNTY — Temperature oscillations in the tropical Pacific have historically had a significant effect on the climate of the western Antarctic Peninsula, according to scientists who studied a 12,000-year fossil record to measure how much glacial ice melted into the sea during that span.

The research is important because the western Antarctic Peninsula is one of the fastest warming regions on the planet, and the fastest warming part of the Southern Hemisphere. The ice sheets of the region may be vulnerable to collapse, and would raise sea level by several meters if the melt.

The study, led by Cardiff University researchers, measured oxygen isotopes in microscopic marine algae fossils to trace glacial ice entering the ocean along the western Antarctic Peninsula. Based on the data, the study concluded that the atmospheric temperatures had a bigger factor than oceanic circulation on warming along the western Antarctic Peninsula than oceanic circulation in the late Holocene (from 3,500-250 years ago). Continue reading

Climate: Antarctic research season starts with aerial surveys

NASA’s Operation IceBridge surveys Thwaites Glacier and Bellinghausen Sea

This NASA photo shows the calving front of Thwaites Ice Shelf looking at the ice below the water’s surface. Note how the water acts as a blue filter.

By Summit Voice

SUMMIT COUNTY — As Arctic sea ice melted away to a new record-low level this summer, global warming deniers tried to deflect attention from the meltdown by emphasizing the growth in Antarctic sea ice.

Of course, the increase in Antarctic sea ice is small compared to the loss of Arctic ice, and there are other hints that Antarctica is set to experience some major changes. In coming decades, entire ice shelves along the coast may crumble into the sea, potentially contributing significantly to sea level rise.

To measure those impending changes, NASA has been doing extensive aerial surveys in Antarctica with Operation IceBridge, and this year’s flying season began productively with a land ice survey of Thwaites Glacier and a sea ice flight over parts of the Bellingshausen Sea. Continue reading

Follow

Get every new post delivered to your Inbox.

Join 7,360 other followers