Informing climate models with rapid chamber measurements of forest carbon uptake
2016 (English)In: Global Change Biology, ISSN 1354-1013, E-ISSN 1365-2486Article in journal (Refereed) In press
Models predicting ecosystem carbon dioxide (CO2) exchange under future climate change rely on relatively few real-world tests of their assumptions and outputs. Here, we demonstrate a rapid and cost-effective method to estimateCO2exchange from intact vegetation patches under varying atmospheric CO2concentrations.We ﬁnd that net ecosys-tem CO2uptake (NEE) in a boreal forest rose linearly by 4.7 0.2% of the current ambient rate for every 10 ppmCO2increase, with no detectable inﬂuence of foliar biomass, season, or nitrogen (N) fertilization. The lack of any clearshort-term NEE response to fertilization in such an N-limited system is inconsistent with the instantaneous downreg-ulation of photosynthesis formalized in many global models. Incorporating an alternative mechanism with consider-able empirical support – diversion of excess carbon to storage compounds – into an existing earth system modelbrings the model output into closer agreement with our ﬁeld measurements. A global simulation incorporating thismodiﬁed model reduces a long-standing mismatch between the modeled and observed seasonal amplitude of atmo-spheric CO2. Wider application of this chamber approach would provide critical data needed to further improvemodeled projections of biosphere–atmosphere CO2exchange in a changing climate.
Place, publisher, year, edition, pages
boreal forest, earth system model, model-data integration, nutrient limitation, photosynthetic downregulation, Pinussylvestris
Earth and Related Environmental Sciences
IdentifiersURN: urn:nbn:se:umu:diva-131516DOI: 10.1111/gcb.13451OAI: oai:DiVA.org:umu-131516DiVA: diva2:1074736