a major process in the the US) and in previously harvested forests replaces carbon lost during previous decades. The VEMAP result suggests that, for the US at least, this process is between 100 and 200 percent of the CO2-effect. This is important for the prediction of future CO2 because while CO2 fertilization will continue for the foreseeable future, regrowth of trees will slow or cease when forests reach maturity or are harvested.

The results of the VEMAP activity are important scientifically because they are the first results that quantify the large-scale effects of the CO2 effect relative to quantitative estimates of actual forest growth. They confirm the growing suspicion of ecologists that CO2 fertilization is merely one of a number of processes resulting in the total uptake of carbon by ecosystems. They contradict the suggestion that North American ecosystem uptake balances its emissions of fossil fuel. The results suggest that when policies are made that requiring knowing ecosystem carbon uptake, policymakers must be aware that ecosystem carbon uptake can vary from year to year by large amounts. Therefore, short-term measurement periods could be very misleading. The high variability of ecosystem processes demonstrate why long term ecological measurements and research is so critical and urgently needed.

'"/>

Contact: David Schimel
dschimel@bgc-jena.mpg.de
49-3641-643729
Max-Planck-Gesellschaft
9-Mar-2000

Page: 1 2 3
Related biology news :

1. New study to investigate demise of coral reef ecosystems
2. All ecosystems are equally productive under drought conditions
3. Biological oceanographers examine regime shifts in complex marine ecosystems
4. Freeing Nemo: Aquarium owners releasing non-native fish could endanger marine ecosystems
5. Faster carbon turnover in basal food-chain levels in aquatic than terrestrial ecosystems
6. URI oceanographer awarded NSF grant to study function of jellyfish in coastal ecosystems
7. Out-of-balance ecosystems play role in demise of amphibian populations
8. Northern climate, ecosystems driven by cycles of changing sunlight
9. Long-term decline of coral reef ecosystems reported
10. All species are not created equal when assessing the impacts of species loss on ecosystems
11. Finicky snails provide new clues to the evolution of coastal ecosystems