The Response of the Physical and Biogeochemical Marine Environment to the Passage of Mediterranean Cyclones in the Presence of Eddies, Gyres, and Marine Heat Wave

Medicanes, a class of the most intense Mediterranean cyclones, are known to have a substantial influence on the physical and biogeochemical properties of the marine environment. Yet, our understanding of how this response under various precyclone sea conditions is still lacking. Here, we conducted a comprehensive analysis of 14 medicanes focusing on the two days before and after their observed maximum intensity. We analyzed the medicane's influence on surface and subsurface physical and biogeochemical properties and also their interactions with various ocean structures in the marine environment. Within the mixed layer, our findings reveal a consistent response to the passage of the medicanes, as they move across regions of warmer or colder sea surface temperatures (SST). Upon moving to warmer SST regions, the response is characterized by an increase in chlorophyll a (Chl a), phytoplankton biomass, nutrients, and dissolved oxygen, as well as a greater drop in the sea temperature, relative to cold SST regions. The presence of warm-core eddies and marine heat waves along the cyclone's track before maximum cyclone intensity significantly affects the dynamics of the medicane with a more pronounced deepening that drives stronger vertical mixing and upwelling than cold-core eddies. These processes favor the injection of nutrients into the ocean's upper layers, driving the observed increase in Chl a concentration and phytoplankton biomass. These findings provide new insights into how ocean-atmosphere coupling may affect extreme Mediterranean cyclones and how they can drive regional marine productivity and ecosystem dynamics.