@misc{ManzoniCapekPoradaetal.2018, author = {Manzoni, Stefano and Capek, Petr and Porada, Philipp and Thurner, Martin and Winterdahl, Mattias and Beer, Christian and Bruchert, Volker and Frouz, Jan and Herrmann, Anke M. and Lindahl, Bjorn D. and Lyon, Steve W. and Šantrůčkov{\´a}, Hana and Vico, Giulia and Way, Danielle}, title = {Reviews and syntheses}, series = {Biogeosciences}, volume = {15}, journal = {Biogeosciences}, number = {19}, publisher = {Copernicus}, address = {G{\"o}ttingen}, issn = {1726-4170}, doi = {10.5194/bg-15-5929-2018}, pages = {5929 -- 5949}, year = {2018}, abstract = {The cycling of carbon (C) between the Earth surface and the atmosphere is controlled by biological and abiotic processes that regulate C storage in biogeochemical compartments and release to the atmosphere. This partitioning is quantified using various forms of C-use efficiency (CUE) - the ratio of C remaining in a system to C entering that system. Biological CUE is the fraction of C taken up allocated to biosynthesis. In soils and sediments, C storage depends also on abiotic processes, so the term C-storage efficiency (CSE) can be used. Here we first review and reconcile CUE and CSE definitions proposed for autotrophic and heterotrophic organisms and communities, food webs, whole ecosystems and watersheds, and soils and sediments using a common mathematical framework. Second, we identify general CUE patterns; for example, the actual CUE increases with improving growth conditions, and apparent CUE decreases with increasing turnover. We then synthesize > 5000CUE estimates showing that CUE decreases with increasing biological and ecological organization - from uni-cellular to multicellular organisms and from individuals to ecosystems. We conclude that CUE is an emergent property of coupled biological-abiotic systems, and it should be regarded as a flexible and scale-dependent index of the capacity of a given system to effectively retain C.}, language = {en} } @misc{ManzoniČapekPoradaetal.2018, author = {Manzoni, Stefano and Čapek, Petr and Porada, Philipp and Thurner, Martin and Winterdahl, Mattias and Beer, Christian and Br{\"u}chert, Volker and Frouz, Jan and Herrmann, Anke M. and Lindahl, Bj{\"o}rn D. and Lyon, Steve W. and Šantrůčkov{\´a}, Hana and Vico, Giulia and Way, Danielle}, title = {Reviews and syntheses}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {1134}, issn = {1866-8372}, doi = {10.25932/publishup-44638}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-446386}, pages = {23}, year = {2018}, abstract = {The cycling of carbon (C) between the Earth surface and the atmosphere is controlled by biological and abiotic processes that regulate C storage in biogeochemical compartments and release to the atmosphere. This partitioning is quantified using various forms of C-use efficiency (CUE) - the ratio of C remaining in a system to C entering that system. Biological CUE is the fraction of C taken up allocated to biosynthesis. In soils and sediments, C storage depends also on abiotic processes, so the term C-storage efficiency (CSE) can be used. Here we first review and reconcile CUE and CSE definitions proposed for autotrophic and heterotrophic organisms and communities, food webs, whole ecosystems and watersheds, and soils and sediments using a common mathematical framework. Second, we identify general CUE patterns; for example, the actual CUE increases with improving growth conditions, and apparent CUE decreases with increasing turnover. We then synthesize > 5000CUE estimates showing that CUE decreases with increasing biological and ecological organization - from uni-cellular to multicellular organisms and from individuals to ecosystems. We conclude that CUE is an emergent property of coupled biological-abiotic systems, and it should be regarded as a flexible and scale-dependent index of the capacity of a given system to effectively retain C.}, language = {en} } @article{KnoblauchBeerLiebneretal.2018, author = {Knoblauch, Christian and Beer, Christian and Liebner, Susanne and Grigoriev, Mikhail N. and Pfeiffer, Eva-Maria}, title = {Methane production as key to the greenhouse gas budget of thawing permafrost}, series = {Nature climate change}, volume = {8}, journal = {Nature climate change}, number = {4}, publisher = {Nature Publ. Group}, address = {London}, issn = {1758-678X}, doi = {10.1038/s41558-018-0095-z}, pages = {309 -- 312}, year = {2018}, abstract = {Permafrost thaw liberates frozen organic carbon, which is decomposed into carbon dioxide (CO2) and methane (CH4). The release of these greenhouse gases (GHGs) forms a positive feedback to atmospheric CO2 and CH4 concentrations and accelerates climate change(1,2). Current studies report a minor importance of CH4 production in water-saturated (anoxic) permafrost soils(3-6) and a stronger permafrost carbon-climate feedback from drained (oxic) soils(1,7). Here we show through seven-year laboratory incubations that equal amounts of CO2 and CH4 are formed in thawing permafrost under anoxic conditions after stable CH4-producing microbial communities have established. Less permafrost carbon was mineralized under anoxic conditions but more CO2-carbon equivalents (CO2Ce) were formed than under oxic conditions when the higher global warming potential (GWP) of CH4 is taken into account(8). A model of organic carbon decomposition, calibrated with the observed decomposition data, predicts a higher loss of permafrost carbon under oxic conditions (113 +/- 58 g CO2-C kgC(-1) (kgC, kilograms of carbon)) by 2100, but a twice as high production of CO2-Ce (241 +/- 138 g CO2-Ce kgC(-1)) under anoxic conditions. These findings challenge the view of a stronger permafrost carbon-climate feedback from drained soils1,7 and emphasize the importance of CH4 production in thawing permafrost on climate-relevant timescales.}, language = {en} }