The Roles of Suspension-Feeding and Flux-Feeding Zooplankton as Gatekeepers of Particle Flux Into the Mesopelagic Ocean in the Northeast Pacific

摘要: Zooplankton are important consumers of sinking particles in the ocean’s twilight zone. However, impact different taxa depends on their feeding mode. In contrast to typical suspension-feeding zooplankton, flux-feeding preferentially consume rapidly-sinking that would otherwise penetrate into deep ocean. To quantify potential two zooplankton (Aulosphaeridae [Rhizaria], and Limacina helicina [euthecosome pteropod]) total community, we measured depth-stratified abundances these organisms during six cruises California Current Ecosystem. Using allometric-scaling relationships, computed percentage carbon flux intercepted by feeders suspension feeders. These estimates were compared direct measurements attenuation made using drifting sediment traps 238U-234Th disequilibrium. We found shallow zone typically ranged from 500 – 1000 µmol organic C remineralized per 10-m vertical depth bin. This equated approximately 6 10% / 10 m. The considered this study could account for a substantial proportion near base euphotic mean attributable Aulosphaeridae was 0.69% m (median = 0.21%/10 m, interquartile range 0.04 0.81%) at maximum abundance (~100 m), which equate ~ range. reached 4.2% when protists most abundant. L. helicina, meanwhile, intercept 0.45 1.6% slightly greater (on average) than Aulosphaeridae. contrast, mesopelagic (including copepods, euphausiids, appendicularians, ostracods) had combined clearance rates 2–81 L m-3 d-1 (mean 19.6 d-1). implies slowly particles, but negligible presumably fecal pellets comprised majority material collected traps. Our results highlight need research focus many potentially act as oceanic