PhD Defense: Anna Jalowska, MASC, UNC-CH

“Response of river coastal margins to human induced variations in sediment supply and accelerated sea-level rise” – Jalowska’s dissertation emphasizes that human-induced modifications to riverine sediment budget and changes in the rate of sea-level rise strongly influence bayhead-delta evolution. The response of bayhead deltas to these alterations is difficult to predict, but important to understand because they can lead to submergence and erosion of deltaic environments and loss of important habitat. Floodplains and the bayhead delta of the Lower Roanoke River, NC have the largest, most pristine bottomland hardwood forest ecosystem remaining in the mid-Atlantic region. The majority of this ecosystem is currently at sea-level elevation and is very vulnerable to sea-level rise and changes in sediment supply. The Lower Roanoke River, NC, has been impacted by human activities (land clearing followed by river damming), and climate change. Using multidisciplinary tools she was able to reconstruct geological history of the Roanoke delta (core descriptions and radiocarbon and ²¹⁰Pb geochronologies) and define sources, fates and pathways of suspended sediments in the floodplains and delta environments on seasonal (radionuclide based sediment fingerprinting) and decadal to monthly (²¹⁰Pb geochronology) time scales.