Pine Island Glacier melting 50% faster

Posted by: Saving Water SA (Cape Town, South Africa) – partnered with Water Rhapsody conservation systems – 26 June 2011

New results from an investigation into a large glacier in Antarctica and its impact on global sea level rise are published this week in the journal Nature Geoscience.

Pine Island Glacier glacier melt rate has increased significantly because more warm water is circulating beneath it.

An international team of scientists from Lamont-Doherty Earth Observatory and British Antarctic Survey has discovered that due to an increased volume of warm water reaching the cavity beneath Pine Island Glacier in West Antarctica, it’s melting 50 percent faster than it was 15 years earlier. The glacier is currently sliding into the sea at a rate of four kilometres (2.5 miles) a year, while its ice shelf (the part that floats on the ocean) is melting at about 80 cubic kilometres a year.

“More warm water from the deep ocean is entering the cavity beneath the ice shelf, and it is warmest where the ice is thickest,” said lead author, Stan Jacobs, an oceanographer at Columbia University’s Lamont-Doherty Earth Observatory.

In 2009, Jacobs and colleagues sailed to the Amundsen Sea aboard the icebreaking ship Nathaniel B. Palmer to study the region’s thinning ice shelves — floating tongues of ice where land bound glaciers meet the sea. One goal was to study oceanic changes near Pine Island Glacier, which they had visited in an earlier trip in 1994. The researchers discovered that melting beneath the ice shelf had risen by about 50 percent. Although regional ocean temperatures had also warmed slightly, by around 0.2 degrees C, that was not enough to account for the jump. Continue reading

Densest whale population observed

Posted by: Saving Water SA (Cape Town, South Africa) – partnered with Water Rhapsody conservation systems – 03 May 2011

Scientists doing observations in the Wilhelmina Bay in the western Antarctic have found an estimated two million tons of krill, and more than 300 humpback whales feeding on them. It is the densest population of these whales ever recorded, more than 15 per square mile.

Virtually all the larger animals of the Antarctic are either directly or indirectly dependent on krill.

The observations were made in May 2009, autumn in the southern hemisphere, and for four weeks, the scientists documented the gigantic assemblage of shrimplike krill and the ways whales fed on them. The researchers tagged 11 whales in Wilhelmina and nearby Andvord Bay, and found they rested during the day, dived to more than 300 yards in the late afternoon, and fed intensively at night as the krill moved toward the surface.

A humpback can consume half a ton of krill a day, but even at that rate, the authors estimate that the daily intake of the 306 whales was less than seven one-thousandths of 1 percent of the available krill.

Still, according to the lead author, Douglas P. Nowacek, an associate professor of marine conservation technology at Duke, the future of whales and krill in the Antarctic remains in doubt.

“Whales are going to have a few bumper years,” he said, because krill have less ice to hide under, leaving them exposed to predators for longer periods. But krill, feed and reproduce under the ice, and with warmer weather and more open water in winter, the population of krill is likely to decline.

“In the long term, krill aren’t getting the protection they need to reproduce effectively,” Dr. Nowacek said, “and if the krill disappear, the whales will, too.”

By: Nicholas Bakalar
Source: NY Times

Grass thrives in warmer Antarctica

Posted by: Saving Water SA (Cape Town, South Africa) – partnered with Water Rhapsody conservation systems – 01 April 2011

Antarctic Hairgrass uses its roots to access nitrogen directly as peptides

One plant species that grows in Antarctica appears to be thriving according to a team of UK scientists. Antarctic Hairgrass (Deschampsia antarctica) is more effective at absorbing organic nitrogen from the soil than the mosses that it lives alongside. This finding has implications for understanding how the nitrogen cycle works and is published this week in the first issue of the journal Nature Climate Change – part of the Nature series.

Samples were collected from the ice-free areas around British Antarctic Survey’s (BAS) Signy Research Station in the sub-Antarctic.

Lead author Dr Paul Hill from Bangor University said, “We think of the Antarctic as a land of snow and ice. But, in summer on the Antarctic Peninsula, and the islands surrounding the frozen centre of the continent, the snow melts and many areas become green with mosses and two species of native flowering plant. As summer air temperatures in the maritime Antarctic have increased by about 1°C over the last 50 years, and Antarctic summers have become longer and warmer, one of these flowering plants, Antarctic Hairgrass (Deschampsia antarctica), has become increasingly widespread.”

Author and principal investigator Professor Davey Jones from Bangor University said, “Plants need nitrogen to grow successfully. In coastal Antarctica, much of the nitrogen is locked in organic matter in the soil, which has been slow to decompose in the cold conditions. This is now becoming more available as temperatures increase.”

Plants absorb nitrogen from organic matter that breaks down in stages, forming peptides, amino acids and then inorganic nitrogen. The team made the discovery that Antarctic Hairgrass uses its roots to access nitrogen directly as peptides, thus bypassing the final stage and using a shorter sequence. By injecting a trackable nitrogen substance into the soil under the Antarctic Hairgrass the team monitored it being absorbed by the plant.

BAS author Kevin Newsham said, “These findings have ramifications far beyond Antarctica. If the roots of plants in temperate and tropical regions are consistently found to absorb organic nitrogen in this way, then it could have implications for the management of agriculture in the future.”

Source: British Antarctic Survey

Emperor Penguin colony disappears

Posted by: Saving Water SA (Cape Town, South Africa) – partnered with Water Rhapsody conservation systems – 12 March 2011

Scientists at British Antarctic Survey (BAS) have recently described the loss of a small colony of emperor penguins on an island off the West Antarctic Peninsula. The loss is attributed to reduced sea ice, which provides an important nesting substrate for the penguins as well as an important foraging habitat. Reporting in the February edition of the scientific journal PLoS ONE researchers from BAS and Scott Polar Research Institute (SPRI) say that this is the first time the disappearance of an emperor penguin colony has been documented.

The small colony of birds on Emperor Island was found in 1948

The small colony of birds on Emperor Island was found in 1948 when scientists observed 150 pairs gathering there to breed. However, since 1970 the numbers have been declining steadily and in 2009 a high resolution survey from the air revealed no remaining trace of the colony. The decline and loss of the colony relates closely to a rise in local air temperature and seasonal changes in sea ice duration, associated with climate change.

Lead author Dr Phil Trathan from British Antarctic Survey says,

“It is not clear whether the colony died out or relocated. Emperor penguins are thought to return each year to the sites where they hatched, but the colonies must sometimes relocate because of changes in the sea ice. It is clear that emperor penguins are vulnerable to changes in sea ice and the one site in Antarctica where we have seen really big changes in ice is the West Antarctic Peninsula. For much of the 20th century, this region has warmed at an unprecedented rate, particularly in recent decades. Continued climate change is likely to impact on future breeding success.”

The paper also explores alternative hypotheses of perhaps why the colony may have disappeared, including possible effects from competition with fisheries, impacts from tourism, disease and unusual weather conditions. The authors suggest that at least the first two of these suggestions can be discounted, and that there are no data to support the remaining two.

The loss of this colony provides important evidence about emperor penguin population trajectories; however, to reduce uncertainty about the risks to emperors, similar studies are needed elsewhere in the Antarctic.

Source: SANAP

Antarctic base becoming prime waterfront property

Posted by: Saving Water SA (Cape Town, South Africa) – partnered with Water Rhapsody conservation systems – 22 February 2011

New Zealand’s Antarctic base is getting closer to becoming prime waterfront property as conditions in the Southern Ocean change.

McMurdo Sound

The breaking-up of sea ice means the waters are now within 1km of Scott Base, providing easier shipping access.

“The last time we saw open sea in front of Scott Base was 1998,” said Antarctica New Zealand chief executive Lou Sanson.

“In the ensuing time we have had these massive icebergs break off the Ross ice shelf that led to these unusual sea ice conditions in McMurdo Sound, and some of the bergs were the bergs that floated up the coast of Dunedin.”

The icebergs, some of which were half the size of Stewart Island, blocked off the entrance to McMurdo Sound and led to “massive multi-year sea ice”, some of which took ships 150km of icebreaking to get in.

Mr Sanson said the breakup could not be put down to climate change.

By: Jarrod Booker
Source: NZ Herald