UNDERSTANDING THE ROLE OF CARBON AND OXYGEN CYCLING IN POND DEVELOPMENT IN A SOUTHERN NEW JERSEY SALT MARSH

Salt marshes are valuable for humans and wildlife alike, acting as habitats, natural filtration systems and storm surge barriers. However, rising sea level and harmful land management techniques have made many salt marshes more susceptible to the formation of ponds on the marsh platform. There has not been wide consensus on the biogeochemical role of ponds in the life cycle of the marsh and it is important to consider how increased pond development may impact in the carbon sequestration potential of marshes in the Mid-Atlantic region, where sea level is rising more quickly (~4 mm/year) than the national mean. In this study we collect biogeochemical data from three distinct ponds within the Seven Mile Island Innovation Lab (SMIIL) near Stone Harbor, New Jersey. Using Onset HOBO loggers in ponds and In-Situ AquaTroll 600s at nearby channel stations recording conductivity, temperature, dissolved oxygen, water level, and pH. This study will use the diel oxygen technique as a proxy to better understand if marine carbon and oxygen dynamics play a role in the formation and expansion of salt ponds, assisted by discrete samples of oxygen, and dissolved inorganic carbon (DIC) and total alkalinity (TA) to close the carbonate chemistry system. To do this, we will calculate fluxes of gross primary productivity (GPP), net primary productivity (NPP), photosynthesis, and respiration. This project aims to augment the understanding of the role that ponds play in the carbon dynamics of the salt marsh platform. We will use measurements from channel stations as baseline data from August 2022 to December 2022 to compare against the three monitored ponds. This analysis will provide important context on the seasonal, tidal and biotic factors influencing pond existence, as well as a more complete understanding of the larger salt marsh metabolism and carbonate chemistry to understand how pond areal extent impacts the ability of salt marshes to be effective carbon sinks.