Fig. 5
Influence of soft tissue and carbonate counter pumps on the CO2 partial pressure of surface waters, as a function of the POC/PIC rain ratio (1/ρ). Solid black line isocontours represent pCO2 (μatm) for constant salinity (34‰), temperature (14 °C), and depleted phosphate (0.5 µmol/kg) and silicate (3 µmol/kg) contents. The solid black arrows represent the effect of biogenic export production in the case of photosynthesis and calcification only. The dashed (or dot-dashed) black and grey arrows illustrate the influence of the biological pump (and particularly the CCP) during the HS1 relative to the ACR, i.e., when 1/ρ decreases by a factor of 1.8, assuming that 10 (or 50%) of the exported POC has been preserved within the sediment, i.e., under two probable export production conditions at site MD07-3088
