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Wednesday, May 20, 2020. 12:00PM. Webinar: Secrets from a two-thousand year old marsh: blue carbon accumulation rates increase with sea level rise. Nathan McTigue, Beaufort Lagoon Ecosystems Long Term Ecological Research. Sponsored by NOAA's National Ocean Service. More information here. 

Earth's vegetated habitats convert atmospheric carbon dioxide (CO2) into plant material, or organic matter (OM), through photosynthesis. In most habitats, OM decomposes back into CO2 within decades; however, OM that becomes buried in coastal wetland habitats such as salt marshes can resist decomposition for thousands of years. Due to concerns over increasing CO2 concentrations in the atmosphere, this mechanism, described as the carbon accumulation rate (CAR), has been assessed as a means to naturally remove CO2 from the atmosphere in hopes of offsetting fossil fuel emissions. Previously calculated rates of OM burial and CAR have been quite variable, making it difficult to calculate the current total burial capacity of the global saltmarsh ecosystems. To better understand this process, we measured CAR in a salt marsh and investigated how this rate changed from 2,400 years ago through present time. We found that while the rate of carbon burial was variable, over the lifetime of this marsh it has been closely correlated with local sea level rise. Moving forward, calculation of CAR must accommodate both the influence of sea level rise while also omitting the recently deposited plant material that will decompose and not contribute to long term OM storage