The role of tides and sea ice on the carbonate chemistry in a coastal polynya in the south-eastern Weddell Sea

. Tides significantly affect polar coastlines by modulating ice shelf melt and modifying shelf water properties through transport and mixing. However, the effect of tides on the marine carbonate chemistry in such regions, especially around Antarctica, remains largely unexplored. We address this topic with two case studies in a coastal polynya in the south-eastern Weddell Sea, neighbouring the Ekström Ice Shelf. The case studies were conducted in January 2015 (PS89) the for PS117. On PS89, dissolved (PO 3 − 4 silicate (SiO 4 3 are similar between both tidal observations, we regard the two case studies as comparable in terms of tidal influence on the system. the accompanying increased fluorescence signal during rising tide on PS89 suggests that photosynthesis in this water has likely contributed to its