Effects of Ocean Acidification on the Ballast of Surface Aggregates Sinking through the Twilight Zone: organic and inorganic carbon content

Incubation Setup
The aggregates were placed inside the settling microcosm. The microcosm was filled with GF/F filtered, artificial seawater (32 psu) with a carbonate chemistry adjusted to the present or future conditions. This reduced the biological activity to the community originally present in the aggregates. The microcosm was continuously pressurized at a rate of 30 MPa/day, until it reached 10 MPa, the equivalent to a depth of 1000 m. The full incubation lasted 80 h. The experiment was triplicated at a pCO2 of 380 µatm and 1100 µatm. Additional incubations of similar duration were done at atmospheric pressure, with triplicates at a pCO2 of 380 µatm and 1100 µatm. These aimed at isolating the effect of the increase in hydrostatic pressure. […]