Dissolved inorganic carbon (DIC) and total alkalinity (TA) are fundamental components of carbonate systems that control pH and buffering capacity of a water body. Three coastal marshes with contrasting salinities in Barataria Basin, Louisiana, USA, were sampled five times between December 2018 and October 2019 to understand seasonal changes in porewater carbonate chemistry and its impact on surrounding water bodies. Porewater DIC and TA increased with depth irrespective of marsh type and ranged from 4.47 to 31.61 mmol/kg and from 1.78 to 28.56 mmol/kg, respectively. The salt marsh had higher porewater DIC and TA compared to the lower salinity intermediate and brackish marshes, probably due to sulfate reduction in the salt marsh. However, [...]
