Along its pathway, the EAC interacts with distinct water masses, where frontal zones can be formed. At these dynamic boundaries, submesoscale processes play a role in lateral/vertical mixing, heat transport and nutrient flux, which can contribute to biomass concentration. Studying these small-scale processes constitutes an observational challenge. We analyse the first comprehensive high-resolution observational dataset on contrasting frontal zones in the Tasman Sea.
We quantify the kinematic properties of 18 contrasting fronts observed in the EAC System, including fronts formed as the EAC interacts with an anticyclonic eddy, with the Tasman Sea waters and with a frontal eddy, and fronts at an isolated long lived cyclonic eddy in the Tasman Sea. While most of the fronts show some level of frontogenesis-induced vertical motion associated with flow strain, the sharpest temperature front (Tasman Front) does not affect directly biogeochemistry below 100 m. The deepest subduction (250 m) of high oxygen surface waters occurs on the edge of the cyclonic eddy, characterised by a deep chlorophyll maximum and the highest integrated chlorophyll, which would not be seen from satellite data. These results highlight the diversity of fronts in this region and how the different subsurface submesoscale processes can impact biological productivity.