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Category Archives: Ecosystem Stress

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18 November 2015, The Conversation, Shrinking Antarctic glaciers could make Adélie penguins unlikely winners of climate change. Penguin numbers exploded in East Antarctica at the end of the last ice age, according to research published today in BMC Evolutionary Biology. Despite their image as cold-loving creatures, the increase in Adélie penguin numbers seems to be closely linked to shrinking glaciers, raising the possibility the these penguins could be winners from current climate change. Adélie penguins are one of only two penguin species that live on the Antarctic continent. Their cousins, emperor penguins, may be the movie stars, but it is the Adélies that are the bigger players in the Southern Ocean. They outnumber emperors by more than ten to one, with a population of over 7.5 million breeding adults and counting. Given the abundance of Adélie penguins and their crucial role in Southern Ocean ecosystems, there has been a great deal of interest in understanding how the species is likely to respond to future climate change. Sensitivity to sea ice Breeding colonies have been monitored for decades to determine the effects of a changing environment on the penguins. A common finding of many of these studies is that Adélies are highly sensitive to sea ice conditions. Unlike emperor penguins, Adélies do not nest on the sea ice, but they must cross it to reach their nests on land. As everyone knows, penguins are not the most efficient walkers, and in years with a lot of sea ice their journeys to and from the ocean to feed their chicks can become lengthy. With a longer wait between meals chicks are less likely to survive. In an extreme case, extensive sea ice at one breeding colony had a devastating impact in 2014, and not a single chick survived. Read More here

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17 November, ABC Science, New map of Earth’s groundwater to help estimate when it may run out. Less than 6 per cent of ground water in the upper two kilometres of the Earth’s landmass is renewable within a human lifetime, according to a new map showing the world’s hidden groundwater. “This has never been known before,” said the study’s lead author, Dr Tom Gleeson of the University of Victoria in Canada. “We already know that water levels in lots of aquifers are dropping. We’re using our groundwater resources too fast -faster than they’re being renewed.” Using data and computer models, an international group of hydrologists has produced the first data-driven estimate of the Earth’s total supply of groundwater. “Since we now know how much groundwater is being depleted and how much there is, we will be able to estimate how long until we run out.” The study, published in the journal Nature Geoscience, estimated a total volume of underground water to be almost 23 million cubic kilometres, of which 0.35 million cubic kilometres is younger than 50 years old. Underground water is found beneath the Earth’s surface and is recharged by rain, snow or water that leaks from the bottom of lakes and rivers. Its age can be a few months to millions of years. It can be found as deep as nine kilometres, according to the United States Geological Survey. “Since we now know how much groundwater is being depleted and how much there is, we will be able to estimate how long until we run out,” Dr Gleeson said. Read More here

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16 November 2015, Science Daily, Bird decline shows that climate change is more than just hot air. Scientists have long known that birds are feeling the heat due to climate change. However, a new study of a dozen affected species in the Western Cape suggests their decline is more complex than previously thought — and in some cases more serious. According to the study, published in Conservation Physiology, by scientists from the Percy Fitzpatrick Institute at the University of Cape Town and Nelson Mandela Metropolitan University, there could be several reasons why birds are being negatively affected by human-made climate change. They suggest that contrary to expectations the birds’ heat tolerance — or lack thereof — is not necessarily the main factor chasing species out of their preferred habitat. Other factors like changing fire and rainfall patterns, and new bird behaviour patterns could also be responsible for the decline, according to the study which includes some well-known species such as the Malachite Sunbird and the Familiar Chat. Lead researcher Susie Cunningham says a better understanding of how climate change affects bird species could help develop conservation strategies to increase chances of survival: “We know climate change is linked to changes in species’ numbers and distributions, but we don’t always know exactly how or why,” Cunningham says. “We need to figure out the factors actually driving declines before we can develop proper conservation measures to halt them.” Read More here

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14 November 2015, Climate News Network, Greenland glaciers’ melting speeds up again. The increasing rate at which Greenland’s glaciers are melting this century has confounded polar scientists.  A massive Greenland glacier that holds enough water to raise sea levels by half a metre is melting at speed, according to a new study. The Zachariae Isstrom in northeast Greenland has entered a phase of accelerated retreat, and is losing mass at the rate of 5 billion metric tons a year, according to US scientists. They report in the journal Science that a succession of aerial surveys combined with multiple satellite observations has established that the base of the glacier is being eroded rapidly by a mix of warmer ocean water and increasing amounts of meltwater from the surface of the Greenland ice sheet. “North Greenland glaciers are changing rapidly,” said Jeremie Mouginot, an earth system scientist at the University of California, Irvine, who led the study. “The shape and dynamics of the Zachariae Isstrom have changed dramatically over the last few years. The glacier is now breaking up and calving high volumes of icebergs into the ocean, which will result in rising sea levels for decades to come.” Read More here

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