Decoding drivers of carbon flux attenuation in the oceanic biological pump.

The biological pump supplies carbon to the oceans' interior, driving long-term carbon sequestration and providing energy for deep-sea ecosystems. Its efficiency is set by transformations of newly formed particles in the euphotic zone, followed by vertical flux attenuation via mesopelagic processes. Depth attenuation of the particulate organic carbon (POC) flux is modulated by multiple processes involving zooplankton and/or microbes.