@article{TreatKleinenBroothaertsetal.2019,
  author    = {Treat, Claire C. and Kleinen, Thomas and Broothaerts, Nils and Dalton, April S. and Dommain, Rene and Douglas, Thomas A. and Drexler, Judith Z. and Finkelstein, Sarah A. and Grosse, Guido and Hope, Geoffrey and Hutchings, Jack and Jones, Miriam C. and Kuhry, Peter and Lacourse, Terri and Lahteenoja, Outi and Loisel, Julie and Notebaert, Bastiaan and Payne, Richard J. and Peteet, Dorothy M. and Sannel, A. Britta K. and Stelling, Jonathan M. and Strauss, Jens and Swindles, Graeme T. and Talbot, Julie and Tarnocai, Charles and Verstraeten, Gert and Williams, Christopher J. and Xia, Zhengyu and Yu, Zicheng and Valiranta, Minna and Hattestrand, Martina and Alexanderson, Helena and Brovkin, Victor},
  title     = {Widespread global peatland establishment and persistence over the last 130,000 y},
  series = {Proceedings of the National Academy of Sciences of the United States of America},
  volume    = {116},
  journal   = {Proceedings of the National Academy of Sciences of the United States of America},
  number    = {11},
  publisher = {National Acad. of Sciences},
  address   = {Washington},
  issn      = {0027-8424},
  doi       = {10.1073/pnas.1813305116},
  pages     = {4822 -- 4827},
  year      = {2019},
  abstract  = {Glacial-interglacial variations in CO2 and methane in polar ice cores have been attributed, in part, to changes in global wetland extent, but the wetland distribution before the Last Glacial Maximum (LGM, 21 ka to 18 ka) remains virtually unknown. We present a study of global peatland extent and carbon (C) stocks through the last glacial cycle (130 ka to present) using a newly compiled database of 1,063 detailed stratigraphic records of peat deposits buried by mineral sediments, as well as a global peatland model. Quantitative agreement between modeling and observations shows extensive peat accumulation before the LGM in northern latitudes (> 40 degrees N), particularly during warmer periods including the last interglacial (130 ka to 116 ka, MIS 5e) and the interstadial (57 ka to 29 ka, MIS 3). During cooling periods of glacial advance and permafrost formation, the burial of northern peatlands by glaciers and mineral sediments decreased active peatland extent, thickness, and modeled C stocks by 70 to 90\% from warmer times. Tropical peatland extent and C stocks show little temporal variation throughout the study period. While the increased burial of northern peats was correlated with cooling periods, the burial of tropical peat was predominately driven by changes in sea level and regional hydrology. Peat burial by mineral sediments represents a mechanism for long-term terrestrial C storage in the Earth system. These results show that northern peatlands accumulate significant C stocks during warmer times, indicating their potential for C sequestration during the warming Anthropocene.},
  language  = {en}
}
@phdthesis{Hoffmann2019,
  author    = {Hoffmann, Mathias},
  title     = {Improving measurement and modelling approaches of the closed chamber method to better assess dynamics and drivers of carbon based greenhouse gas emissions},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-421302},
  school      = {Universit{\"a}t Potsdam},
  pages     = {xx, 204, xxix},
  year      = {2019},
  abstract  = {The trace gases CO2 and CH4 pertain to the most relevant greenhouse gases and are important exchange fluxes of the global carbon (C) cycle. Their atmospheric quantity increased significantly as a result of the intensification of anthropogenic activities, such as especially land-use and land-use change, since the mid of the 18th century. To mitigate global climate change and ensure food security, land-use systems need to be developed, which favor reduced trace gas emissions and a sustainable soil carbon management. This requires the accurate and precise quantification of the influence of land-use and land-use change on CO2 and CH4 emissions. A common method to determine the trace gas dynamics and C sink or source function of a particular ecosystem is the closed chamber method. This method is often used assuming that accuracy and precision are high enough to determine differences in C gas emissions for e.g., treatment comparisons or different ecosystem components. However, the broad range of different chamber designs, related operational procedures and data-processing strategies which are described in the scientific literature contribute to the overall uncertainty of closed chamber-based emission estimates. Hence, the outcomes of meta-analyses are limited, since these methodical differences hamper the comparability between studies. Thus, a standardization of closed chamber data acquisition and processing is much-needed. Within this thesis, a set of case studies were performed to: (I) develop standardized routines for an unbiased data acquisition and processing, with the aim of providing traceable, reproducible and comparable closed chamber based C emission estimates; (II) validate those routines by comparing C emissions derived using closed chambers with independent C emission estimates; and (III) reveal processes driving the spatio-temporal dynamics of C emissions by developing (data processing based) flux separation approaches. The case studies showed: (I) the importance to test chamber designs under field conditions for an appropriate sealing integrity and to ensure an unbiased flux measurement. Compared to the sealing integrity, the use of a pressure vent and fan was of minor importance, affecting mainly measurement precision; (II) that the developed standardized data processing routines proved to be a powerful and flexible tool to estimate C gas emissions and that this tool can be successfully applied on a broad range of flux data sets from very different ecosystem; (III) that automatic chamber measurements display temporal dynamics of CO2 and CH4 fluxes very well and most importantly, that they accurately detect small-scale spatial differences in the development of soil C when validated against repeated soil inventories; and (IV) that a simple algorithm to separate CH4 fluxes into ebullition and diffusion improves the identification of environmental drivers, which allows for an accurate gap-filling of measured CH4 fluxes. Overall, the proposed standardized data acquisition and processing routines strongly improved the detection accuracy and precision of source/sink patterns of gaseous C emissions. Hence, future studies, which consider the recommended improvements, will deliver valuable new data and insights to broaden our understanding of spatio-temporal C gas dynamics, their particular environmental drivers and underlying processes.},
  language  = {en}
}