@article{CoutureIrrgangPollardetal.2018,
  author    = {Couture, Nicole J. and Irrgang, Anna Maria and Pollard, Wayne and Lantuit, Hugues and Fritz, Michael},
  title     = {Coastal erosion of permafrost soils along the yukon coastal plain and fluxes of organic carbon to the canadian beaufort sea},
  series = {Journal of geophysical research : Biogeosciences},
  volume    = {123},
  journal   = {Journal of geophysical research : Biogeosciences},
  number    = {2},
  publisher = {American Geophysical Union},
  address   = {Washington},
  issn      = {2169-8953},
  doi       = {10.1002/2017JG004166},
  pages     = {406 -- 422},
  year      = {2018},
  abstract  = {Reducing uncertainties about carbon cycling is important in the Arctic where rapid environmental changes contribute to enhanced mobilization of carbon. Here we quantify soil organic carbon (SOC) contents of permafrost soils along the Yukon Coastal Plain and determine the annual fluxes from coastal erosion. Different terrain units were assessed based on surficial geology, morphology, and ground ice conditions. To account for the volume of wedge ice and massive ice in a unit, SOC contents were reduced by 19\% and sediment contents by 16\%. The SOC content in a 1m(2) column of soil varied according to the height of the bluff, ranging from 30 to 662kg, with a mean value of 183kg. Forty-four per cent of the SOC was within the top 1m of soil and values varied based on surficial materials, ranging from 30 to 53kg C/m(3), with a mean of 41kg. Eighty per cent of the shoreline was erosive with a mean annual rate of change of -0.7m/yr. This resulted in a SOC flux per meter of shoreline of 132kg C/m/yr, and a total flux for the entire 282km of the Yukon coast of 35.5 x 10(6) kg C/yr (0.036 Tg C/yr). The mean flux of sediment per meter of shoreline was 5.3 x 10(3) kg/m/yr, with a total flux of 1,832 x 10(6)kg/yr (1.832 Tg/yr). Sedimentation rates indicate that approximately 13\% of the eroded carbon was sequestered in nearshore sediments, where the overwhelming majority of organic carbon was of terrestrial origin. Plain Language Summary The oceans help slow the buildup of carbon dioxide (CO2) because they absorb much of this greenhouse gas. However, if carbon from other sources is added to the oceans, it can affect their ability to absorb atmospheric CO2. Our study examines the organic carbon added to the Canadian Beaufort Sea from eroding permafrost along the Yukon coast, a region quite vulnerable to erosion. Understanding carbon cycling in this area is important because environmental changes in the Arctic such as longer open water seasons, rising sea levels, and warmer air, water and soil temperatures are likely to increase coastal erosion and, thus, carbon fluxes to the sea. We measured the carbon in different types of permafrost soils and applied corrections to account for the volume taken up by various types of ground ice. By determining how quickly the shoreline is eroding, we assessed how much organic carbon is being transferred to the ocean each year. Our results show that 36 x 10(6) kg of carbon is added annually from this section of the coast. If we extrapolate these results to other coastal areas along the Canadian Beaufort Sea, the flux of organic carbon is nearly 3 times what was previously thought.},
  language  = {en}
}
@article{MohrKorupUlloaetal.2017,
  author    = {Mohr, Christian Heinrich and Korup, Oliver and Ulloa, Hector and Iroume, Andres},
  title     = {Pyroclastic Eruption Boosts Organic Carbon Fluxes Into Patagonian Fjords},
  series = {Global biogeochemical cycles},
  volume    = {31},
  journal   = {Global biogeochemical cycles},
  publisher = {American Geophysical Union},
  address   = {Washington},
  issn      = {0886-6236},
  doi       = {10.1002/2017GB005647},
  pages     = {1626 -- 1638},
  year      = {2017},
  abstract  = {Fjords and old-growth forests store large amounts of organic carbon. Yet the role of episodic disturbances, particularly volcanic eruptions, in mobilizing organic carbon in fjord landscapes covered by temperate rainforests remains poorly quantified. To this end, we estimated how much wood and soils were flushed to nearby fjords following the 2008 eruption of Chaiten volcano in south-central Chile, where pyroclastic sediments covered >12km(2) of pristine temperate rainforest. Field-based surveys of forest biomass, soil organic content, and dead wood transport reveal that the reworking of pyroclastic sediments delivered similar to 66,500+14,600/-14,500tC of large wood to two rivers entering the nearby Patagonian fjords in less than a decade. A similar volume of wood remains in dead tree stands and buried beneath pyroclastic deposits (similar to 79,900+21,100/-16,900tC) or stored in active river channels (5,900-10,600tC). We estimate that bank erosion mobilized similar to 132,300(+21,700)/(-30,600)tC of floodplain forest soil. Eroded and reworked forest soils have been accreting on coastal river deltas at >5mmyr(-1) since the eruption. While much of the large wood is transported out of the fjord by long-shore drift, the finer fraction from eroded forest soils is likely to be buried in the fjords. We conclude that the organic carbon fluxes boosted by rivers adjusting to high pyroclastic sediment loads may remain elevated for up to a decade and that Patagonian temperate rainforests disturbed by excessive loads of pyroclastic debris can be episodic short-lived carbon sources. Plain Language Summary Fjords and old-growth forests are important sinks of organic carbon. However, the role of volcanic eruptions in flushing organic carbon in fjord landscapes remains unexplored. Here we estimated how much forest vegetation and soils were lost to fjords following the 2008 eruption ofunknownChaiten volcano in south-central Chile. Pyroclastic sediments obliterated near-pristine temperateunknownrainforest, and the subsequent reworking of these sediments delivered in less than a decade similar to 66,000 tC of large wood to the mountain rivers, draining into the nearby Patagonian fjords. A similar volume of wood remains in dead tree stands and buried beneath pyroclastic deposits or stored in active riverunknownchannels. We estimate that similar to 130,000 tC of organic carbon-rich soil was lost to erosion, thus adding to the carbon loads. While much of the wood enters the long-shore drift in the fjord heads, the finerunknownfraction from eroded forest soils is likely to be buried in the fjords at rates that exceed regional estimates by an order of magnitude. We anticipate that these eruption-driven fluxes will remain elevated forunknownthe coming years and that Patagonian temperate rainforests episodically switch from carbon sinks to hitherto undocumented carbon sources if disturbed by explosive volcanic eruptions.},
  language  = {en}
}