Warmer Ecosystems

Research by scientists at Queen Mary, University of London has found that a predicted rise in global temperature of 4°C by 2100 could lead to a 13% reduction in ecosystems' ability to absorb carbon dioxide (CO2) from the atmosphere.

Research by scientists at Queen Mary, University of London has found that a predicted rise in global temperature of 4°C by 2100 could lead to a 13% reduction in ecosystems' ability to absorb carbon dioxide (CO2) from the atmosphere. (Credit: Image courtesy of Queen Mary, University of London)

"Photosynthesis by plants absorbs CO2 while respiration by animals returns CO2 to the atmosphere. Respiration has a higher 'activation energy' than photosynthesis meaning that it increases more rapidly with increasing temperature. So if climate change raises environmental temperatures, the balance between respiration and photosynthesis in the ecosystem will change, favouring more respiration and less CO2 absorption."

The work is complemented by another paper published this month by Dr Guy Woodward and other Queen Mary colleagues in the journal Global Change Biology. This research compared animals living in 15 similar Icelandic streams, a rare long-term 'natural experiment' in which geothermal activity heats some streams up to 45°C. The unique situation meant researchers could study how temperature affects Arctic ecosystems, where climate change is predicted to cause a rise of around 7.5°C within the next century.

"We saw longer food-chains, with predators becoming bigger and more abundant as temperatures increased from 5°C to 25°C. We also have more recent (as yet unpublished) data collected from the Icelandic streams by colleagues at the Macaulay Institute that show similar patterns to those seen in the experimental ponds: namely the warmer streams emitted far more CO2 than the cooler streams and acted as sources of carbon, rather than sinks."

Source: www.sciencedaily.com