Microscopy and DNA‐based characterization of sinking particles at the Bermuda Atlantic Time‐series Study station point to zooplankton mediation of particle flux

摘要: Plankton‐derived, microscopic, and macroscopic sinking aggregates constitute most of the particulate organic carbon (POC) flux in the oceans. While the flux of particulate organic matter and associated elements has been quantified at the Bermuda Atlantic Time‐series Study (BATS) station for several decades, we lack an understanding of the source and composition of sinking particles, as well as the fate of predominant phytoplankton taxa. We determined the composition of individual sinking particles and their microbial communities in the upper 300 m depth at the BATS station in fall 2017 and spring 2018 by image analysis and V4 amplicon sequencing of the 16S and 18S rRNA genes. The sinking particles were primarily composed of phytodetrital aggregates, fecal aggregates, and fecal pellets. In the fall, phytodetrital aggregates were numerically dominant and drove the majority of the POC flux; however, in …