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A stubborn little seabird that survives and raises young byconsuming up to 65,000 tiny crustaceans each day has so far adaptedto climate change in the far north Atlantic Ocean with aplomb,surprising an international team of scientists expecting to findplunging survival rates in the warming seas. The little auk the most common seabird along the Arctic coasts of Greenlandand Spitzbergen showed no sign of weight loss or reproductiveproblems at three summer colonies despite rising temperatures thathave alterered food sources, according to a new study published this week the journal Marine Ecology Progress. So how has this five-ounce, eight-inch-tall planktivore coped? Surprisingly, the birds have managed to make up for the warmingof surface waters in the Greenland Sea by altering their diet andextending the duration of their foraging trips at sea, explainedlead researcher David Gremillet and eight co-authors in a story released by the Paris-based Center for Functional and Evolutionary Ecology . They travel farther and for longer in order to feed in areaswhere foraging is more successful. More warming, more trouble? Still, the scientists warned that the adaptive capacity of littleauks may max out if waters continue to warm at the same rate.Scientists are now investigating whether global warming has changedlittle auk survival during winter. It seems that little auks have reached the limits of theirphysiological and behavioral capacities, they wrote here . More intense warming could therefore cause their decline, aswell as a major disruption of marine ecosystems in the Arctic. The study is part of a growing body of work investigating howseabirds respond to rising ocean temperatures and shifting foodsources. Since birds like little auks subsist off creatures nearthe bottom of the marine food web, they can often serve asindicators of ecological health as sort of a canary-in-the-coal-mine for the oceans. Because of their specialized diet and high food intake, littleauks are a reliable indicator for testing the impact of climatechange on this region, the scientists explained here . Some 40 to 80 million of the birds converge every summer on theremote ice-bound shores of Greenland, Spitzbergen and other islands in the Arctic reaches of the Atlantic Ocean. Researcher from APU Little Auks feed almost entirely on tiny zooplankton that arecaught during wing-propelled dives, added Anchorage seabirdbiologist Ann Harding , then a research associate at Alaska Pacific University, on a web page with details about the research . Parent Little Auks carry these zooplankton back to their chickat the colony in a throat pouch, which can hold more than 15,000individual prey items. The birds prefer Arctic waters that support various kinds ofcopepods, including a high fat Calanus hyperboreus that thrives in very cold water. But they will also target theless nutritious and smaller C. finmarchicus , which shows up in more temperate waters, the scientistsexplained. For three summers between 2005 and 2007, the researchers studied three colonies of little auks on either side of the Greenland Sea, with atemperature range difference from the coldest site to the warmestsite of about 9 degrees Fahrenheit. In a way, it allowed them tocompare the present little auk status to their future prospects ina warming ocean. The warmest site, located in Spitsbergen, reproduces theconditions predicted for the late 21st century in the coldest site(East Greenland), the scientists explained. Such temperaturedifferences lead to major changes in the abundance and average sizeof zooplankton, reducing the quality of little auks' food resources(copepods). The little auks off the more-frigid coast of Greenland were able tofind gobs of the high-fat copepods while the little auks onSpitzbergen with much warmer water were forced to rely on thesmaller copepod with its reduced energy bang for the buck. The birds prevailed in both locales, doing whatever they needed todo to get enough to eat and feed their babies. Contrary to our hypothesis, the birds responded to a wide rangeof sea surface temperatures via plasticity of their foragingbehaviour, allowing them to maintain their fitness levelsunchanged, wrote Gr millet and his eight collaborators in the abstract . For more details about the research, plus blog entries from aCalifornia school teacher who participated in 2007, check out this site , including this photo page . Contact Doug O'Harra at doug(at)alaskadispatch.com. I am an expert from multilayerpcbboard.com, while we provides the quality product, such as China High Density Interconnect , Prototype PCB Board Manufacturer, Aluminum Based PCB,and more.
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