Particulate biogenic barium tracer of mesopelagic carbon remineralization in the Mediterranean Sea (PEACETIME project)

Abstract. We report on the sub-basin variability in particulate organic carbon (POC) remineralization western and central Mediterranean Sea late spring during PEACETIME (ProcEss studies at Air–sEa Interface after dust deposition MEditerranean sea) cruise. POC rates were estimated using excess biogenic barium (Baxs) inventories mesopelagic layers (100–1000 m depth) compared with prokaryotic heterotrophic production (PHP). Baxs-based (MRs) ranged from 25±2 to 306±70 mgCm-2d-1. MRs larger Algero-Provençal (ALG) Basin than Tyrrhenian (TYR) Ionian (ION) basins. Our Baxs integrated PHP data also indicated that significant occurred down 1000 depth ALG contrast ION TYR basins, where was mainly located above 500 depth. propose higher deeper sustained by an additional particle export event driven deep convection. The (in basins) presented impact of a previous event, as reflected our Al water column concentrations. basins showed small-scale heterogeneity processes, Tyrr long-duration station. This linked mosaic blooming non-blooming patches reported this area In (ALG Basin), (ION lower restricted upper layer