Abstract. In the ocean, remineralisation rate associated with sinking particles is a crucial variable. Since the 90's, particulate biogenic barium (Baxs) has been used as an indicator of carbon remineralization by applying a transfer function relating Baxs to O2 consumption (Dehairs's transfer function, Southern Ocean-based). Here, we tested its validity in the Mediterranean Sea (ANTARES / EMSO-LO) for the first time by investigating connections between Baxs, prokaryotic heterotrophic production (PHP) and oxygen consumption (JO2-Opt; optodes measurement). We show that: (1) higher Baxs (409 pM; 100–500 m) in situations where integrated PHP (PHP100/500 = 0.90) is located deeper, (2) higher Baxs with increasing JO2-Opt, and (3) similar magnitude between JO2-Opt (3.14 mmol m−2 d−1; 175–450 m) and JO2-Ba (4.59 mmol m−2 d−1; transfer function). Overall, Baxs, PHP and JO2 relationships follow trends observed in the Southern Ocean. We believe that such transfer function could apply in the Mediterranean Sea with no restriction.
On the barium - oxygen consumption relationship in the Mediterranean Sea: implications for mesopelagic marine snow remineralisation
