Respiration rate scales inversely with sinking speed of settling marine
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.  demonstrated that slow moving particles are
respired faster than motionless particles, whereas García‐Martín et al.
 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
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.