Metabolic alkalinity release from large port facilities (Hamburg, Germany) and impact on coastal carbon storage

Abstract. Metabolic activities in estuaries, especially these of large rivers, profoundly affect the downstream coastal biogeochemistry. Here, we unravel impacts industrial port facilities, showing that elevated metabolic activity Hamburg (Germany) increases total alkalinity (TA) and dissolved inorganic carbon (DIC) runoff to North Sea. The imports particulate carbon, organic nitrogen (PIC, POC, PON) from upstream Elbe River can fuel up 90 % TA generated entire estuary via calcium carbonate (CaCO3) dissolution. remaining at least 10 generation be attributed anaerobic processes such as denitrification remineralized PON or other pathways. Estuary a whole adds approximately 15 overall DIC runoff. Both magnitude partitioning among appear sensitive climatic anthropogenic changes. Thus, with increased loads, ocean (in particular) would act stronger CO2 sink, resulting changes system's capacity store CO2.