A vast reservoir of reduced carbon resides in the ocean at depth > 1000 m as deep-sea dissolved organic carbon (DOC) that has long been thought to be extremely refractory to microbial degradation. However, previous observations of bulk DOC concentration gradients in deep waters across major ocean basins along with independent measurements of 14C-DOC imply potential bioavailability of deep-sea DOC. Yet, there is no direct evidence for such assertation. In this talk, I will present our recent efforts in isolating organic molecules from deep-sea waters for carefully‑designed bioassay experiments that directly test the bioavailability of deep-sea DOC. Our new observations provide direct evidence for the presence of certain bioavailable organic molecules in the deep ocean where they can be accessible by microbes on time scales of weeks to months.

溶解有机碳,深海,微生物可可利用性,分子组分