Sinking marine particles have been studied for a long time to understand its role in carbon sequestration. Traditionally, sinking speed and respiration rates have been treated as independent variables, but two recent papers suggest a connection albeit in contrasting directions. Alcolombri et al. [2021] demonstrated that slow moving particles are respired faster than motionless particles, whereas García‐Martín et al. [2021] found that respiration rate was higher for suspended particles compared with slow- and fast-sinking particles. Here we collected settling aggregates and determined respiration rates of particles sinking at different velocities. The average respiration rate of fast sinking particles (>100 m d^-1) was 0.12 d^-1. Slower sinking particles (<50 m d^-1) had on average higher and more variable respiration rates. These findings provide insights into the efficiency of the biological carbon pump and help resolve the apparent discrepancy in the recent studies of the correlation between respiration and sinking speed.

Alcolombri, U., F. J. Peaudecerf, V. I. Fernandez, L. Behrendt, K. S. Lee, and R. Stocker (2021), Sinking enhances the degradation of organic particles by marine bacteria, Nat Geosci, 1-6.

García‐Martín, E. E., K. Davidson, C. Davis, C. Mahaffey, S. Mcneill, D. Purdie, and C. Robinson (2021), Low contribution of the fast‐sinking particle fraction to total plankton metabolism in a temperate shelf sea, Glob Biogeochem Cycles, 35(9), e2021GB007015.