High nitrate concentrations in U.S. Rockies' high elevation lakes caused by melting glaciers

October 12, 2010 By Jasmine Saros

Melting glaciers in the American West are releasing chemicals that cause ecosystem changes in alpine lakes, including large quantities of nitrogen that reduces biodiversity, according to an international research team led by University of Maine paleoecologist Jasmine Saros.

The study, funded by a $500,000 grant from the National Science Foundation, determined that glaciers in alpine watersheds are the largest geomorphic and biogeographic influences of nitrate concentrations in high-elevation ecosystems.

Nitrogen is a key limiting nutrient in alpine lake ecosystems that can dramatically affect ecosystem productivity and species diversity.

The researchers from UMaine, Miami University, the U.S. Geological Survey, University of Nebraska-Lincoln and the University of Alberta studied the ecosystems of 26 high-elevation lakes in the northern and central U.S. where atmospheric nitrogen deposition is low and where alpine glaciers have receded substantially during the 20th century. Twelve of the lakes were fed by melt from glaciers and snow, the rest by snowpack melt water alone.

Those lakes fed by and snow had up to 100 times higher nitrate concentrations and lower algal biomass than those fed solely by snowpack. In those lakes affected by glacial melt, sediment diatom assemblages had less taxonomic richness compared to the diversity present throughout the past century.

However, the water columns in the glacier and snowpack-fed lakes were more transparent, altering the depths reached by ultraviolet and photosynthetically active radiation, which also has the potential to change diatom communities.

Given predictions that alpine will disappear form the U.S. Rockies by 2030, these observations raise serious questions concerning the future biogeochemical and ecological trajectories of hundreds of lake ecosystems within this vast region, according to the researchers, writing in the journal Environmental Science & Technology.

Explore further: Alpine lakes beginning to show effects of climate change

Related Stories

Glaciers feeding Ganges may melt down

July 1, 2005

Indian scientists say carbon dioxide and other emissions will cause the melt down of glaciers feeding the Ganges River before the century's end.

Glacial melting may release pollutants in the environment

October 21, 2009

Those pristine-looking Alpine glaciers now melting as global warming sets in may explain the mysterious increase in persistent organic pollutants in sediment from certain lakes since the 1990s, despite decreased use of those ...

Norwegian glaciers could melt completely

April 7, 2006

Climate researchers predict that the approximately 1,600 Norwegian glaciers could melt completely away in course of the next 100 years. This would mean that only 28 glaciers would remain in the country.

Recommended for you

Researchers pin down one source of a potent greenhouse gas

November 20, 2017

A study of a Lake Erie wetland suggests that scientists have vastly underestimated the number of places methane-producing microbes can survive—and, as a result, today's global climate models may be misjudging the amount ...

1 comment

Adjust slider to filter visible comments by rank

Display comments: newest first

2.3 / 5 (3) Oct 13, 2010
Frankly, I am disappointed that NSF spent a half million dollars to obtain a report that "Melting glaciers in the American West are releasing chemicals that cause ecosystem changes in alpine lakes, including large quantities of nitrogen that reduces biodiversity".

With kind regards,
Oliver K. Manuel
Former NASA Principal
Investigator for Apollo

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.