Global warming has ecosystem double whammy

RENO, Nev., Sept. 22 (UPI) -- U.S. scientists have found one abnormally warm year can suppress the amount of carbon dioxide absorbed by some grassland ecosystems for as long as two years.

Researchers at the Desert Research Institute said the findings from a four-year study of sealed, 12-ton containerized grassland plots is said to be the first to quantitatively track the response in carbon dioxide uptake and loss in entire ecosystems during anomalously warm years.

"The 'lagged' responses that carry over for more than one year are a dramatic reminder of the fragility of ecosystems that are key players in global carbon sequestration," said research Professor Jay Arnone.

The four-year Desert Research Institute study involved native Oklahoma tall grass prairie ecosystems that were sealed inside four, living-room-sized environment chambers. The dozen 12-ton, 6-foot-deep plots were extracted intact from the University of Oklahoma's prairie research facility near Norman, Okla. Scientists replicated the daily and seasonal changes in temperature and rainfall that occur in the wild.

They found ecosystems exposed to an anomalously warm year had a net reduction in CO2 uptake for at least two years.

The research is detailed in the journal Nature.