How NMP-POC aggregates affect to the deep ocean microbial communities?

Abstract

This study is a review of current knowledge about microbes in the deep ocean. The vertical connectivity between bathypelagic and superficial microbial communities is still poorly understood. Few recent studies have considered that surface and deep-water communities may be connected through sinking and water mass advection processes, neglecting the role of the driver of these interactions, that is to say, the passive NMP-POC aggregate fluxes. Regarding this assumption, a series of questions have been raised of this issue, which are: (i) do microbes that sink ever return to the surface ocean, or is there a dispersal mechanism that brings them back to the surface? (ii) If the transported microbes depend directly on the processes occurring at the ocean surface, how does variability in NMP-POC aggregates sinking rates affect to the deep ocean communities? (iii) Are the microbial organisms arriving from the surface, adhered to NMP-POC aggregates, determining the biogeography of the deep ocean? The summarizing responses are: (i) The microbe dispersion to the deep ocean would be conditioned by the oceanic circulation to return to the surface ocean, and by the abundance and wind speed to return to the atmosphere. (ii) Prokaryotes that sink with the aggregates of NMP-POC and are released when they reach to the depths clearly affect the structure of bathypelagic communities. (iii) In general terms NMP-POC aggregates provides a continuous supply of viable microbe migrants to the deep ocean.