A global assessment of mesozooplankton respiration in the ocean

Published data on the biomass and specific respiration rates of mesozooplankton in the oceans across all latitudes were combined to assess their community respiration on a global basis. Mesozooplankton biomass was higher in boreal/anti-boreal and polar waters, intermediate in equatorial waters and lowest in the subtropical gyres. Specific respiration rates were the highest in equatorial waters and decreased rapidly poleward. Global community respiration of mesozooplankton in the upper 200 m of the oceans integrated over all latitudes was 10.4 +/- 3.7 (SE) Gt C year(-1) (n = 838). Below the epipelagic zone, mesozooplankton respiration living in the mesopelagic (200-1000 m) and bathypelagic (below 1000 m) zones was estimated as 2.2 +/- 0.4 (n = 57) and 0.40 +/- 0.2 (n = 12) Gt C year(-1), respectively. Thus, global depth-integrated mesozooplankton respiration was 13.0 +/- 4.2 Gt C year(-1) (17-32% of global primary production), which is 3-8-fold higher than the values assigned to mesozooplankton respiration in recent estimates of total respiration in the ocean. Thus, it appears that mesozooplankton represent a major, but neglected component of the carbon cycle in the ocean.