Temperature sensitivity of remineralisation of organic matter in the mesopelagic zone

Remineralisation of organic matter increases the concentration of dissolved inorganic carbon (DIC) in the mesopelagic zone (100-1000m) where DIC subsequently is transported back to the surface layer through physical mixing and advection processes. Thereby, remineralisation processes working in the upper ocean have a significant impact on surface pCO2 levels. Heterotrophic processes regulating the remineralisation of organic matter in the mesopelagic zone are expected to be influenced by temperature, and changes in upper ocean temperatures due to climate change therefore can alter the biological drawdown of CO2 (the "biological pump"). However, this temperature sensitivity of the "deep" part of the biological pump is largely unknown. Here we present and analyse new data for quantifying the temperature sensitivity of remineralisation of organic matter in the global ocean.