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  • Sediment Carbon and Nitrogen and Environmental Data, Middle Island Sinkhole, 2007–2021

    work
    Creator:
    Howard, Cecilia M., Velazquez, Diana, Rico, Kathryn I., and Sheldon, Nathan D.
    Description:
    This study combines a field survey time series with analysis of remotely and locally sensed environmental and climate data. Field survey data consists of sediment chemistry from hand-push cores, and includes %Corg, %N, δ13Corg, Corg:N, collection month and year, and depth in sediment. Climate and environmental data for the region around Middle Island Sinkhole was pulled from publicly available NOAA databases (ERDDAP, National Data Buoy Center, NWS) for as much of the same time period as the sediment data as was available. These data included general weather information from the NDBC and NWS (air temperature, wind speed, wind direction, gust speed, monthly precipitation totals), as well as satellite-derived environmental data from a 0.25° area centered on MIS (ice cover, lake surface temperature, CDOM, DOC, Chlorophyll, suspended minerals). Data were processed to monthly and annual averages as described below in order to compare to sinkhole sediment chemistry. Abstract: Records of recent past climate provide an essential window into understanding how changing climate influences environments and ecosystems such as lakes. Sediment carbon and nitrogen chemistry can offer insight into productivity and biochemistry, and anoxic sediments can often preserve short-term changes in these signals. We found that seasonal and annual changes in local ice season, chlorophyll, and precipitation influenced the amount and isotopic composition of carbon reaching the sediments of Middle Island Sinkhole, an anoxic sinkhole in Lake Huron. Carbon and nitrogen signals reflected the year or season of sample collection in sediments as deep as 12 cm. Our findings demonstrate that declining ice cover in this part of the Great Lakes is leading to increased export of organic carbon into sediments, but that in situ sediment processes may make teasing out short-term changes from sediment cores difficult even in an anoxic setting.
    Keyword:
    Carbon burial, Great Lakes, Ice cover, Sediment carbon, Sediment nitrogen, Anoxia, and Geosciences
    Citation to related publication:
    Howard, C.M., et al. (in prep). Climate-driven changes in sediment carbon and nitrogen of an anoxic Lake Huron sinkhole.
    Discipline:
    Science