Glaciers along the Gulf of Alaska are enriching stream and near shore marine ecosystems from a surprising source ancient carbon contained in glacial runoff, researchers from four universities and the U.S. Forest Service report in the December 24, 2009, issue of the journal Nature*.
In spring 2008, Eran Hood, associate professor of hydrology with the Environmental Science Program at the University of Alaska Southeast, set out to measure the nutrients that reach the gulf from five glaciated watersheds he can drive to from his Juneau office. "We don't currently have much information about how runoff from glaciers may be contributing to productivity in downstream marine ecosystems. This is a particularly critical question given the rate at which glaciers along the Gulf of Alaska are thinning and receding" said Hood.
Hood then asked former graduate school colleague Durelle Scott, now an assistant professor of biological systems engineering at Virginia Tech, to help analyze the organic matter and nutrient (nitrogen and phosphorus) loads being exported from the Juneau-area study watersheds. "Because there are few reports of nutrient yields from glacial watersheds, Eran and I decided to compare the result from a non-glacial watershed with those of a watershed partially covered by a glacier and a watershed fully covered by a glacier," said Scott.
Hood and Scott's initial findings, reported in the September 2008 issue of the journal Nature Geoscience (http://www.nature.com/ngeo/journal/v1/n9/abs/ngeo280.html), presented something of a mystery. As might be expected, there is more organic matter from a forested watershed than from a fully or partially glacier-covered watershed. With soil development, organic matter is transported from the landscape during runoff events. However, there was still a considerable amount of organic carbon exported from the glaciated landscape.
How can a glacier be a source of the organi
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