Forgotten Link in Carbon Cycle
Tuesday, 2. December 2008, 15:00:39
It turns out that microorganisms in rivers and streams play a crucial role in the global carbon cycle. Microorganisms such as bacteria and single celled algae in rivers and streams decompose organic matter as it flows downstream. They convert the carbon it contains into carbon dioxide, which is then released to the atmosphere. Recent estimates conclude there is a net flux, or outgassing, of carbon dioxide from the world's rivers and streams to the atmosphere of at least two-thirds to three-quarters of a gigatonne (Gt) of carbon per year. This flux has not been taken into account in the models of the global carbon cycle used to predict climate change.
For comparison I bring a diagram of the carbon cycle taken from Wikipedia. It shows sinks measured in Gt and fluxes measured in Gt per year. Rivers are pictured, but there are no data for the rivers. This is symptomatic.
Surface water drainage networks perfuse and integrate the landscape, across the whole planet, but they are missing from all global carbon cycling reports, even from the IPCC (Intergovernmental Panel on Climate Change). The latest estimates of how much carbon is transferred to the atmosphere from rivers and streams are probably too conservative. According to research presented at the "Complex Systems: Water and Life" Frontiers of Science conference, organized by the European Science Foundation (ESF) and COST, 29-31 October 2008, Taormina, Sicily, the actual outgassing of carbon dioxide is probably closer to 2 Gt of carbon per year.
Two gigatonnes of carbon per year is close to half the estimated net primary production of the world's vegetation each year. Realising that this quantity of carbon may be delivered straight back to the atmosphere, rather than being taken to the ocean where some of it is removed by marine organisms and ends up in sediment, could have profound consequences for our understanding of the (carbon) system.
We need as many accurate elements as possible to approve the accuracy of current climate models in predicting future levels of global warming - carbon flux from rivers to the atmosphere could be one such item.
• http://www.eurekalert.org/pub_releases/2008-12/esf-rac120108.php
• http://www.physorg.com/news147358157.html
For comparison I bring a diagram of the carbon cycle taken from Wikipedia. It shows sinks measured in Gt and fluxes measured in Gt per year. Rivers are pictured, but there are no data for the rivers. This is symptomatic.
Surface water drainage networks perfuse and integrate the landscape, across the whole planet, but they are missing from all global carbon cycling reports, even from the IPCC (Intergovernmental Panel on Climate Change). The latest estimates of how much carbon is transferred to the atmosphere from rivers and streams are probably too conservative. According to research presented at the "Complex Systems: Water and Life" Frontiers of Science conference, organized by the European Science Foundation (ESF) and COST, 29-31 October 2008, Taormina, Sicily, the actual outgassing of carbon dioxide is probably closer to 2 Gt of carbon per year.
Two gigatonnes of carbon per year is close to half the estimated net primary production of the world's vegetation each year. Realising that this quantity of carbon may be delivered straight back to the atmosphere, rather than being taken to the ocean where some of it is removed by marine organisms and ends up in sediment, could have profound consequences for our understanding of the (carbon) system.
We need as many accurate elements as possible to approve the accuracy of current climate models in predicting future levels of global warming - carbon flux from rivers to the atmosphere could be one such item.
• http://www.eurekalert.org/pub_releases/2008-12/esf-rac120108.php
• http://www.physorg.com/news147358157.html
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