PORTLAND, Ore. December 23, 2009. A study recently completed in the gulf coast of Alaska by federal and university researchers has found that as glacial ice disappears, the production and export of high- quality food from glacial watersheds to marine ecosystems may disappear too. This trend could have serious consequences for marine food webs.
The study, "Glaciers as a source of ancient and labile organic matter to the marine environment," was recently published in the December 24, 2009, issue of the journal Nature.
The research, which was conducted on 11 coastal watersheds in the Gulf of Alaska, has documented an interesting paradox with important implications for coastal ecosystems. "Glacial watersheds comprise 30 percent of the Tongass National Forest and supply about 35 to 40 percent of the stream discharge," says Rick Edwards, a coauthor on the study. "These watersheds export dissolved organic matter that is remarkably biologically active in contrast to that found in other rivers. Generally, scientists expect that organic matter decreases in its quality as a food source as it ages, becoming less and less active over time."
But the dissolved organic material discharged from the glacial watersheds in this study was almost 4,000 years old; yet surprisingly, more than 66 percent of it was rapidly metabolized by marine microbes into living biomass to support marine food webs, adds Edwards.
The study was conducted by Eran Hood, University of Alaska Southeast; Jason Fellman, University of Alaska Fairbanks; Robert Spencer and Peter Hernes, University of California Davis; Rick Edwards and David D'Amore, Pacific Northwest (PNW) Research Station, USDA Forest Service; and Durelle Scott, Virginia Tech.
Edwards and D'Amore partnered with their university colleagues to characterize the dominant types of watersheds and variables that control the volume and chemistry of water flowing into the gulf. The study was led by Ho
|Contact: Sherri Richardson Dodge|
USDA Forest Service, Pacific Northwest Research Station