fauna

unknown-endangered:

What is coral bleaching?

Coral bleaching is a serious problem facing corals all over the world. It is a general stress response of corals, and is the result of several different factors, especially increasing sea temperature. This causes the zooxanthellae, or symbiotic algae that live with the coral, to be expelled. The coral becomes white or “bleached”, and is unable to obtain the nutrients it needs, as it relies on its photosynthetic zooxanthellae.

Increasing sea temperatures are the cause of mass bleaching, but the following threats are responsible for small-scale bleaching:

• Decline in zooplankton, causing starvation.
• Ocean acidification.
• Bacterial infections.
• Changes in ocean salinity.

The most severely affected coral reefs include the Great Barrier Reef, reefs in the Indian Ocean, around the Maldives, Seychelles, and Hawaii. Up to 90% of corals have been lost from these locations. 

A huge range of sea life depends on coral reefs for survival, so the disappearance of the corals would have a dire effect on the oceans. In turn, this would impact on many people who rely on the sea for their food and livelihoods. 

Photo: John Pascal.

Melting Glaciers Cause 1/3 of the World’s Sea Level Rise

by Stephanie Pappas

The world’s glaciers lost 260 gigatons of water each year between 2003 and 2009, making these rivers of ice responsible for almost a third of sea-level rise in that time, new research finds.

The study, to appear tomorrow (May 17) in the journal Science, used multiple methods to pin down estimates of how much ice is lost from glaciers. The results suggest that on-the-ground measurements yield estimates that are too extreme, but some satellite methods don’t go far enough…

(read more: Live Science)                

(photo: Aletsch Glacier, Switzerlan; credit: Frank Paul)

Greenland’s Glacial Melt May Slow, Study Suggests

by Becky Oskin

Greenland’s galloping glaciers will likely slow their rapid retreat in the coming century, scientists project based on a new computer modeling study.

In the study, published today (May 8) in the journal Nature, researchers resolve one of the biggest uncertainties about Greenland’s future contributions to sea-level rise: the behavior of its outlet glaciers. These massive ice rivers drain to the ocean, adding both surface runoff water and icebergs to the sea. The researchers discovered that Greenland’s outlet glaciers retreat in episodic pulses, which account for the past 10 years of dramatic ice loss…

(read more: Our Amazing Planet)

New study finds no evidence for theory that humans wiped out Australian megafauna

Most species of gigantic animals that once roamed Australia had disappeared by the time people arrived, a major review of the available evidence has concluded.

The research challenges the claim that humans were primarily responsible for the demise of the megafauna in a proposed “extinction window” between 40,000 and 50,000 years ago, and points the finger instead at climate change.An international team led by the University of New South Wales, and including researchers at the University of Queensland, the University of New England, and the University of Washington, carried out the study. It is published in the Proceedings of the National Academy of Sciences…

(read more: PhysOrg)

(image: This is a reconstruction of an extinct marsupial lion — Thylacoleo carnifex. Artwork: Peter Schouten)

Why Elk Are Robbing Birds

by Sonya Auer

… One of the most challenging tasks facing ecologists today is determining how species are responding to rapid changes in climate, and the consequences.

In the high-elevation canyons along the southern edge of the Colorado Plateau in central Arizona, I worked with my colleague Thomas Martin of the U.S. Geological Survey to study how more than two decades of changing winter temperatures have hurt spring breeding success for birds. This harm results not just from changing temperature, but stem indirectly from climate impacts on elk, small predators and even the forest the birds inhabit.

As winter temperatures on the plateau increase, more precipitation is falling as rain rather than snow. Less snow means it’s easier for big animals like elk to hang around and find food, so they are now remaining at these high elevation sites throughout winter rather than migrating to lower elevations like they have done historically. But, elk opting to overwinter in the canyons is not boding well for the local plants and birds, like the Red-faced Warbler…

(read more: Live Science)                 (photo: Thomas Martin)

_____________________________

Sonya Auer, of the Department of Environmental Conservation at the University of Massachusetts, Amherst, recently won the Elton Prize, from the British Ecological Society for her research and writing.She contributed this article to LiveScience’s Expert Voices: Op-Ed & Insights.

Color-Changing Hare Can’t Keep Up With Climate Change

by Elizabeth Pennisi

For hares, fashion is a life or death proposition. Whereas Peter Rabbit could always jump down his hole to escape a fox, his cousin, the hare, has to rely on blending in with his environment to avoid detection. But as the climate warms, hares may no longer be able to stay in sync with their environment, according to a new study. The animals will be switching from earthy brown to snowy white or vice versa at the wrong time and becoming targets for hungry predators.

After more than a decade of studying snowshoe hares in the Rocky Mountains, L. Scott Mills, a wildlife biologist at the University of Montana, Missoula, noticed that the animals were beginning to stick out more than usual. In winter their coats turn white; in summer they are a mottled brown. But Mills was beginning to see white hares on brown backgrounds…

(read more: Science/AAAS)                 

(photo: L. Scott Mills et al., PNAS Early Edition, 2013)

Andean Tropical Glaciers Going Fast, May Soon Be Gone

by Paul Brown, Climate News Network

The glaciers of the tropical Andes have shrunk by between 30 and 50 percent in 30 years and many will soon disappear altogether, cutting off the summer water supply for millions of people, according to scientists studying the region’s climate.

Their findings are particularly significant because glaciers in the tropics, 99 percent of which are in the Andes, are regarded as among the most sensitive indicators of climate change on the planet, according to the Intergovernmental Panel on Climate Change (IPCC).

In the Andes glaciers contribute to irrigation, hydroelectricity generation, and water supply. For example, 15 percent of the water consumed in La Paz, the capital of Bolivia, comes from glaciers, a figure that doubles in the summer. The region, with 3.5 million people, is heavily dependent on melt water for its survival (and see our story of 25 January, Andean glaciers show record melting)…

(read more: http://www.climatecentral.org/news/andes-tropical-glaciers-are-going-fast-may-soon-be-gone-15844)

(photo: Edubucher | wikipedia)

mad-as-a-marine-biologist:

“Various processes are known to enhance the ocean’s ability to store carbon. Sperm whales increase the levels of primary production and carbon export to the deep ocean by depositing iron rich faeces into surface waters of the Southern Ocean.

The iron rich faeces causes phytoplankton to grow and take up more carbon from the atmosphere. When the phytoplankton dies, it sinks to the deep ocean and takes the atmospheric carbon with it. By reducing the abundance of sperm whales in the Southern Ocean, whaling has resulted in an extra 2 million tonnes of carbon remaining in the atmosphere each year. “ 

As if sperm whales weren’t cool enough already. 

Source | Journal article | Photo 1 | Photo 2

In Sign of Warming, 1,600 Years of Ice in Andes Melted in 25 Years

by Justin Gillis

Glacial ice in the Peruvian Andes that took at least 1,600 years to form has melted in just 25 years, scientists reported Thursday, the latest indication that the recent spike in global temperatures has thrown the natural world out of balance.

The evidence comes from a remarkable find at the margins of the Quelccaya ice cap in Peru, the world’s largest tropical ice sheet. Rapid melting there in the modern era is uncovering plants that were locked in a deep freeze when the glacier advanced many thousands of years ago.

Dating of those plants, using a radioactive form of carbon in the plant tissues that decays at a known rate, has given scientists an unusually precise method of determining the history of the ice sheet’s margins…

(read more: http://www.nytimes.com/2013/04/05/world/americas/1600-years-of-ice-in-perus-andes-melted-in-25-years-scientists-say.html)   

(photo: Lonnie G. Thompson, Ohio St. Univ.)

After 25 million years, Australia’s mountain pygmy possum could disappear if temperatures continue to rise

by Lawrence Karol

A one-degree change in temperature doesn’t sound like much, but it could mark the difference between life and death for Australia’s mountain pygmy possum. For this little guy—about 5.5 inches in size, weighing only 0.4 to 1.8 ounces—climate change, not natural predators, is public enemy number one.

The possums, also known as Burramys parvus, hibernate in rock piles for six months of the year when snow covers the mountains above New South Wales and Victoria. Linda Broome is a senior researcher at the National Parks and Wildlife Service in New South Wales who has studied the possums for years. As a result of her research, she came to the realization that with a one-degree change in temperature, the snow field was going to disappear.

“The snow cover is extremely important to the Burramys because it provides them with insulation,” Michael Archer, a paleontologist and naturalist at the University of New South Wales who has worked with Broome, tells TakePart.

“The temperatures in those alpine zones get well below zero, and if there’s not an insulating blanket of snow, the cold will penetrate the cracks in the boulder field where the Burramys live, and the possums won’t survive.”…

(read more: TakePart.org)     

(photo: Hayley Bates, Univ. of New South Wales)