Intertidal regions changing coastal alkalinity: The Wadden Sea‐North Sea tidally coupled bioreactor

A study on the Wadden Sea revealed significant seasonal increases in total alkalinity (TA) of 100–150 μmol kg−1, equivalent to a production rate of 11.7–26.8 mmol m−2 d−1 during spring and summer. This change was not attributed to riverine contributions but likely linked to seasonal organic matter production and processing in coastal and nearshore regions. The research used high-frequency (10 min) TA measurements along a ship's route, combining a FerryBox with a flow-through setup, to demonstrate dynamic carbon fluxes between the Wadden Sea and North Sea. The findings suggest that bottom sediments and tidally coupled biogeochemical processes mediate this alkalinity change, with a ~4-month lag possibly explained by labile organic matter supply and temperature-dependent remineralization via aerobic and anaerobic pathways.

Voynova, Y. G., Petersen, W., Gehrung, M., Aßmann, S., & King, A. L. (2018). Intertidal regions changing coastal alkalinity: The Wadden Sea‐North Sea tidally coupled bioreactor. Limnology and Oceanography, 64(3), 1135–1149. Portico. https://doi.org/10.1002/lno.11103