Variability in the vertical flux of microorganisms and biogenic material in the epipelagic zone of a North Pacific central gyre station (original) (raw)

Previously published data on vertical fluxes of particulate carbon (PC), nitrogen (PN), organisms (MICRO), and extracted adenosine triphosphate (ATP) into screened sediment traps (335/xm) from the VERTEX 5 and ADIOS I programs are reexamined as they relate to biogeochemical cycling and oceanic productivity. The four stations discussed represent an oligotrophic to mesotrophic gradient in total primary production (PT), ranging from 245 to 1141 mg C m -2 d -1 and a gradient in PC flux from the euphotic zone, ranging from 12 to 164 mg C m -2 d -• for particles <335/xm in diameter. Vertical fluxes of PC, PN, MICRO, and ATP decreased as negative power functions of depth with significantly higher depth-dependent losses for ATP fluxes. The flux of intact biota (free, particleassociated, and some active "swimmers," measured microscopically and by extracted ATP) decreased rapidly in the upper 200 m, contributing as much as 52.4% at the most productive station and as little as 1.6% to the flux of PC at oligotrophic stations, remaining relatively constant or increasing slightly (to 3.4 -9.6% PC flux) between 200 and 2000 m. Multiple regression analyses, expressing fluxes as • Now at Paper number 91GB01543. 0886-6236/91/91GB-01543510.00