@article{GrotheerMeyerRiedeletal.2020,
  author    = {Grotheer, Hendrik and Meyer, Vera and Riedel, Theran and Pfalz, Gregor and Mathieu, Lucie and Hefter, Jens H. and Gentz, Torben and Lantuit, Hugues and Mollennauer, Gesine and Fritz, Michael},
  title     = {Burial and origin of permafrost-derived carbon in the nearshore zone of the southern Canadian Beaufort Sea},
  series = {Geophysical research letters},
  volume    = {47},
  journal   = {Geophysical research letters},
  number    = {3},
  publisher = {Wiley},
  address   = {Hoboken, NJ},
  issn      = {0094-8276},
  doi       = {10.1029/2019GL085897},
  pages     = {11},
  year      = {2020},
  abstract  = {Detailed organic geochemical and carbon isotopic (delta C-13 and Delta C-14) analyses are performed on permafrost deposits affected by coastal erosion (Herschel Island, Canadian Beaufort Sea) and adjacent marine sediments (Herschel Basin) to understand the fate of organic carbon in Arctic nearshore environments. We use an end-member model based on the carbon isotopic composition of bulk organic matter to identify sources of organic carbon. Monte Carlo simulations are applied to quantify the contribution of coastal permafrost erosion to the sedimentary carbon budget. The models suggest that similar to 40\% of all carbon released by local coastal permafrost erosion is efficiently trapped and sequestered in the nearshore zone. This highlights the importance of sedimentary traps in environments such as basins, lagoons, troughs, and canyons for the carbon sequestration in previously poorly investigated, nearshore areas. Plain Language Summary Increasing air and sea surface temperatures at high latitudes leads to accelerated thaw, destabilization, and erosion of perennially frozen soils (i.e., permafrost), which are often rich in organic carbon. Coastal erosion leads to an increased mobilization of organic carbon into the Arctic Ocean, which there can be converted into greenhouse gases and may therefore contribute to further warming. Carbon decomposition can be limited if organic matter is efficiently deposited on the seafloor, buried in marine sediments, and thus removed from the short-term carbon cycle. Basins, canyons, and troughs near the coastline can serve as sediment traps and potentially accommodate large quantities of organic carbon along the Arctic coast. Here we use biomarkers (source-specific molecules), stable carbon isotopes, and radiocarbon to identify the sources of organic carbon in the nearshore zone of the southern Canadian Beaufort Sea near Herschel Island. We quantify the contribution of coastal permafrost erosion to the sedimentary carbon budget of the area and estimate that more than a third of all carbon released by local permafrost erosion is efficiently trapped in marine sediments. This highlights the importance of regional sediment traps for carbon sequestration.},
  language  = {en}
}
@article{HartmanGentzSchilleretal.2018,
  author    = {Hartman, Jan F. and Gentz, Torben and Schiller, Amanda and Greule, Markus and Grossart, Hans-Peter and Ionescu, Danny and Keppler, Frank and Martinez-Cruz, Karla and Sepulveda-Jauregui, Armando and Isenbeck-Schroeter, Margot},
  title     = {A f ast and sensitive method for the continuous in situ determination of dissolved methane and its delta C-13-isotope ratio in surface waters},
  series = {Limnology and Oceanography-methods},
  volume    = {16},
  journal   = {Limnology and Oceanography-methods},
  number    = {5},
  publisher = {Wiley},
  address   = {Hoboken},
  issn      = {1541-5856},
  doi       = {10.1002/lom3.10244},
  pages     = {273 -- 285},
  year      = {2018},
  abstract  = {A fast and sensitive method for the continuous determination of methane (CH4) and its stable carbon isotopic values (delta C-13-CH4) in surface waters was developed by applying a vacuum to a gas/liquid exchange membrane and measuring the extracted gases by a portable cavity ring-down spectroscopy analyser (M-CRDS). The M-CRDS was calibrated and characterized for CH4 concentration and delta C-13-CH4 with synthetic water standards. The detection limit of the M-CRDS for the simultaneous determination of CH4 and delta C-13-CH4 is 3.6 nmol L-1 CH4. A measurement precision of CH4 concentrations and delta C-13-CH4 in the range of 1.1\%, respectively, 1.7 parts per thousand (1 sigma) and accuracy (1.3\%, respectively, 0.8 parts per thousand [1 sigma]) was achieved for single measurements and averaging times of 10 min. The response time tau of 57 +/- 5 s allow determination of delta C-13-CH4 values more than twice as fast than other methods. The demonstrated M-CRDS method was applied and tested for Lake Stechlin (Germany) and compared with the headspace-gas chromatography and fast membrane CH4 concentration methods. Maximum CH4 concentrations (577 nmol L-1) and lightest delta C-13-CH4 (-35.2 parts per thousand) were found around the thermocline in depth profile measurements. The M-CRDS-method was in good agreement with other methods. Temporal variations in CH4 concentration and delta C-13-CH4 obtained in 24 h measurements indicate either local methane production/oxidation or physical variations in the thermocline. Therefore, these results illustrate the need of fast and sensitive analyses to achieve a better understanding of different mechanisms and pathways of CH4 formation in aquatic environments.},
  language  = {en}
}