Nedbrytning av naturligt organiskt material: kemisk diversitet och reaktivitet
Tidsperiod: 2011-01-01 till 2013-12-31
Projektledare: Lars Tranvik
Budget: 3 400 000 SEK
Large quantities of DOC (dissolved organic carbon) are washed from the terrestrial environment into inland waters, where it is degraded and evaded as CO2 and CH4 to the atmosphere, buried in the sediment, or transported to the ocean. The resulting carbon fluxes, although so far poorly constrained, are significant at the scale of the global carbon cycle. The chemical complexity of DOC results in a reactivity continuum. However, it is typically still viewed it as one homogeneous black box, without acknowledging its heterogeneous degradation kinetics. We intend to investigate the relationships between chemodiversity and reactivity of DOC in inland waters. The overall purpose is to improve our understanding of the overall regulation of DOC mineralization, as well as decay patterns of individual organic compounds. The kinetics of degradation at the landscape scale will be elucidated by application of new mathematical modeling approaches to existing and newly collected data sets. The study of degradation at the detailed level will employ state-of-the-art mass spectrometry to generate detailed chemical information. The specific goals of the project are to 1) provide robust probability distributions of OC reactivity continuums from a variety of ecosystems and pools, 2) simulate microbial and photochemical loss of DOC for a set of different case study conditions, and 3) experimentally reveal the relationships between chemodiversity and the continuum of reactivity in natural DOC.