TY  - JOUR
A1  - Knoblauch, Christian
A1  - Beer, Christian
A1  - Liebner, Susanne
A1  - Grigoriev, Mikhail N.
A1  - Pfeiffer, Eva-Maria
T1  - Methane production as key to the greenhouse gas budget of thawing permafrost
JF  - Nature climate change
N2  - 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.
Y1  - 2018
U6  - https://doi.org/10.1038/s41558-018-0095-z
SN  - 1758-678X
SN  - 1758-6798
VL  - 8
IS  - 4
SP  - 309
EP  - 312
PB  - Nature Publ. Group
CY  - London
ER  - 
TY  - JOUR
A1  - Manzoni, Stefano
A1  - Capek, Petr
A1  - Porada, Philipp
A1  - Thurner, Martin
A1  - Winterdahl, Mattias
A1  - Beer, Christian
A1  - Bruchert, Volker
A1  - Frouz, Jan
A1  - Herrmann, Anke M.
A1  - Lindahl, Bjorn D.
A1  - Lyon, Steve W.
A1  - Šantrůčková, Hana
A1  - Vico, Giulia
A1  - Way, Danielle
T1  - Reviews and syntheses
BT  - Carbon use efficiency from organisms to ecosystems - definitions, theories, and empirical evidence
JF  - Biogeosciences
N2  - 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.
Y1  - 2018
U6  - https://doi.org/10.5194/bg-15-5929-2018
SN  - 1726-4170
SN  - 1726-4189
VL  - 15
IS  - 19
SP  - 5929
EP  - 5949
PB  - Copernicus
CY  - Göttingen
ER  - 
TY  - JOUR
A1  - Reichstein, Markus
A1  - Bahn, Michael
A1  - Ciais, Philippe
A1  - Frank, Dorothea
A1  - Mahecha, Miguel D.
A1  - Seneviratne, Sonia I.
A1  - Zscheischler, Jakob
A1  - Beer, Christian
A1  - Buchmann, Nina
A1  - Frank, David C.
A1  - Papale, Dario
A1  - Rammig, Anja
A1  - Smith, Pete
A1  - Thonicke, Kirsten
A1  - van der Velde, Marijn
A1  - Vicca, Sara
A1  - Walz, Ariane
A1  - Wattenbach, Martin
T1  - Climate extremes and the carbon cycle
JF  - Nature : the international weekly journal of science
N2  - The terrestrial biosphere is a key component of the global carbon cycle and its carbon balance is strongly influenced by climate. Continuing environmental changes are thought to increase global terrestrial carbon uptake. But evidence is mounting that climate extremes such as droughts or storms can lead to a decrease in regional ecosystem carbon stocks and therefore have the potential to negate an expected increase in terrestrial carbon uptake. Here we explore the mechanisms and impacts of climate extremes on the terrestrial carbon cycle, and propose a pathway to improve our understanding of present and future impacts of climate extremes on the terrestrial carbon budget.
Y1  - 2013
U6  - https://doi.org/10.1038/nature12350
SN  - 0028-0836
VL  - 500
IS  - 7462
SP  - 287
EP  - 295
PB  - Nature Publ. Group
CY  - London
ER  - 
TY  - JOUR
A1  - Frank, Dorothe A.
A1  - Reichstein, Markus
A1  - Bahn, Michael
A1  - Thonicke, Kirsten
A1  - Frank, David
A1  - Mahecha, Miguel D.
A1  - Smith, Pete
A1  - Van der Velde, Marijn
A1  - Vicca, Sara
A1  - Babst, Flurin
A1  - Beer, Christian
A1  - Buchmann, Nina
A1  - Canadell, Josep G.
A1  - Ciais, Philippe
A1  - Cramer, Wolfgang
A1  - Ibrom, Andreas
A1  - Miglietta, Franco
A1  - Poulter, Ben
A1  - Rammig, Anja
A1  - Seneviratne, Sonia I.
A1  - Walz, Ariane
A1  - Wattenbach, Martin
A1  - Zavala, Miguel A.
A1  - Zscheischler, Jakob
T1  - Effects of climate extremes on the terrestrial carbon cycle: concepts, processes and potential future impacts
JF  - Global change biology
N2  - Extreme droughts, heat waves, frosts, precipitation, wind storms and other climate extremes may impact the structure, composition and functioning of terrestrial ecosystems, and thus carbon cycling and its feedbacks to the climate system. Yet, the interconnected avenues through which climate extremes drive ecological and physiological processes and alter the carbon balance are poorly understood. Here, we review the literature on carbon cycle relevant responses of ecosystems to extreme climatic events. Given that impacts of climate extremes are considered disturbances, we assume the respective general disturbance-induced mechanisms and processes to also operate in an extreme context. The paucity of well-defined studies currently renders a quantitative meta-analysis impossible, but permits us to develop a deductive framework for identifying the main mechanisms (and coupling thereof) through which climate extremes may act on the carbon cycle. We find that ecosystem responses can exceed the duration of the climate impacts via lagged effects on the carbon cycle. The expected regional impacts of future climate extremes will depend on changes in the probability and severity of their occurrence, on the compound effects and timing of different climate extremes, and on the vulnerability of each land-cover type modulated by management. Although processes and sensitivities differ among biomes, based on expert opinion, we expect forests to exhibit the largest net effect of extremes due to their large carbon pools and fluxes, potentially large indirect and lagged impacts, and long recovery time to regain previous stocks. At the global scale, we presume that droughts have the strongest and most widespread effects on terrestrial carbon cycling. Comparing impacts of climate extremes identified via remote sensing vs. ground-based observational case studies reveals that many regions in the (sub-)tropics are understudied. Hence, regional investigations are needed to allow a global upscaling of the impacts of climate extremes on global carbon-climate feedbacks.
KW  - carbon cycle
KW  - climate change
KW  - climate extremes
KW  - climate variability
KW  - disturbance
KW  - terrestrial ecosystems
Y1  - 2015
U6  - https://doi.org/10.1111/gcb.12916
SN  - 1354-1013
SN  - 1365-2486
VL  - 21
IS  - 8
SP  - 2861
EP  - 2880
PB  - Wiley-Blackwell
CY  - Hoboken
ER  - 
TY  - GEN
A1  - Manzoni, Stefano
A1  - Čapek, Petr
A1  - Porada, Philipp
A1  - Thurner, Martin
A1  - Winterdahl, Mattias
A1  - Beer, Christian
A1  - Brüchert, Volker
A1  - Frouz, Jan
A1  - Herrmann, Anke M.
A1  - Lindahl, Björn D.
A1  - Lyon, Steve W.
A1  - Šantrůčková, Hana
A1  - Vico, Giulia
A1  - Way, Danielle
T1  - Reviews and syntheses
BT  - carbon use efficiency from organisms to ecosystems – definitions, theories, and empirical evidence
T2  - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
N2  - 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.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1134 
KW  - gross primary production
KW  - net primary production
KW  - plant respiration
KW  - microbial carbon
KW  - stoichiometric controls
KW  - growth efficiency
KW  - bacterial growth
KW  - excess carbon
KW  - soil
KW  - matter
Y1  - 2021
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-446386
SN  - 1866-8372
IS  - 1134
ER  -