Seminar: Antonio B. Rodriguez – UNC IMS

UNC-CH’s Department of Marine Sciences is proud to host a guest seminar by Antonio B. Rodriguez. This event is scheduled for Wednesday, January 27th, at 12:30 pm. This seminar is remote only and will be broadcast live online via Zoom (Meeting ID: 934 0604 8353).

Presenter Affiliation: Professor, Institute of Marine Sciences, University of North Carolina at Chapel Hill

Title: Spatial and temporal variations in salt marsh carbon accumulation rates

Abstract: Salt marsh has an unparalleled capacity for accumulating and storing organic carbon as compared to other coastal and terrestrial vegetated habitats. The large carbon stock that many salt marshes form is primarily a result of the rapid vertical accretion of carbonaceous sediments and the high preservation of buried organic carbon, but salt marsh area has been declining. Habitat conservation and restoration are often touted as viable means to mitigate salt marsh losses and burgeoning global carbon dioxide levels. Under the Paris Agreement, nations can offset greenhouse gas emissions by managing coastal ecosystems such as salt marsh; however, measurements of salt marsh carbon accumulation rates (CAR) vary globally from 18 to 1713 g C m-2 yr-1 (average of 244.7 ± 26.1 g C m-2 yr-1), creating large uncertainty in monetizing carbon credits or appraising the value of restoration projects. The large range of salt marsh CAR integrated across various time scales of measurement within regions could be masking well-defined patterns related to ontogeny, landscape setting, and sea-level rise and this study aims to measure CAR at transgressive and regressive salt marshes. We hypothesize as the age of the saltmarsh decreases, CAR increases because of the proportion of labile to recalcitrant carbon increases and the space available for new salt-marsh sediment to accumulate increases. To test this hypothesis, we measured organic carbon concentrations and radiocarbon dated the basal saltmarsh peat in 22 cores from seven salt marshes in North Carolina. These data extend from the late Holocene to present and show that CAR variability is strongly linked to salt-marsh evolution and applying an average CAR to a salt marsh is an oversimplification. Explicating the drivers of salt marsh CAR variability, beyond broad regional groupings and time scales of interest, is important for pricing carbon accurately, setting expectations for the effectiveness of restoration projects at mitigating greenhouse-gas emissions, and assessing impacts of coastal landscape conversion.