Impacts of a Hurricane-Induced Storm Surge on Trace-Metal Cycling in a Spatially Heterogeneous Estuary

Abstract:

Estuarine sediments naturally sequester carbon and contaminants/toxins such as arsenic, lead, and excess zinc through interactions with mineral surfaces. These organic matter-mineral and contaminant-mineral assemblages in soils/sediments are thus important for global ecological health because they attenuate the release of carbon and contaminants from sediments, thus potentially limiting global greenhouse gas (GHG) flux to the atmosphere and mobilization of contaminants to waterways and food supplies. However, the stability of these organic matter-mineral and contaminant-mineral assemblages may change with dynamic redox conditions and rapid changes in solution-phase chemistry brought on by storm surges. Here, we report results of sediment biogeochemistry in a costal Delaware estuary before, during, and after a storm surge due to Hurricane Joaquin in 2015. We show enhanced trace-metal release from mineral to solution phase as subsites that had been slightly reducing became more reducing due to surge. These data have implications for the impact of storm surges on trace-metal cycling as the climate shifts.