Marine Life Finds Feast in Alaskan Glacial Meltwater

In a recent Alaska study, a team of environmental scientists has found that there is a surprising bounty of food available to marine life contained in the water delivered by melting glaciers.

Apart from long-term patterns of glacial growth or shrinkage, mountain glaciers advance and retreat on an annual seasonal basis as the seasons change. The meltwater that comes off of a glacier has long been understood to be high in inorganic material, such as sand, silt and clay, that is trapped in the ice and ground into ever smaller bits underneath the glacier, under the tremendous weight of all that ice.

A forested watershed, with abundant plant life and productive soils, will certainly display substantial amounts of nitrogen and phosphorous that are available to support micro- and macro-organisms alike. Until now, not much thought had been given to how much organic material might be in the stream water of a glacial stream.

As reported by PhysOrg, a team led by hydrologist Eran Hood from the University of Alaska Southeast collected and analyzed samples of glacial meltwater from several Alaskan glaciers, and the results were initially puzzling. While the inorganic content was what would be expected, the team found surprisingly high levels of organic carbon, a compound that is capable of being put to good use by the marine life living in the waters that eventually receive these meltwater streams.

Hood and team, in their study currently published in the journal Nature, theorize that the carbon originally came from vast forests that were overrun by the glaciers as they advanced several thousand years ago. This ancient carbon is now understood to play a role in the chemistry of the meltwater, and of the estuaries and bays of the marine environment.

Photo courtesy of Rich Englebrecht, via Wikimedia Commons