![]() Let us know how this access is important for you. Many UC-authored scholarly publications are freely available on this site because of the UC's open access policies. Our results highlight the need for a greater research focus on the many taxa that potentially act as flux feeders in the oceanic twilight zone. This implies a substantial impact on slowly sinking particles, but a negligible impact on the presumably rapidly sinking fecal pellets that comprised the majority of the material collected in sediment traps. Bacteria and zooplankton solubilize and consume POC to support their metabolism, but the relative importance of bacteria vs. In contrast, suspension-feeding zooplankton in the mesopelagic (including copepods, euphausiids, appendicularians, and ostracods) had combined clearance rates of 2-81 L m-3 day-1 (mean of 19.6 L m-3 day-1). The downward flux of particulate organic carbon (POC) decreases significantly in the oceanÂs mesopelagic or ‘twilight’ zone due both to abiotic processes and metabolism by resident biota. helicina, meanwhile, could intercept 0.45-1.6% of carbon flux/10 m, which was slightly greater (on average) than the Aulosphaeridae. The maximum flux attenuation attributable to Aulosphaeridae reached 4.2%/10 m when these protists were most abundant. The mean flux attenuation attributable to Aulosphaeridae was 0.69%/10 m (median = 0.21%/10 m, interquartile range = 0.04-0.81%) at their depth of maximum abundance (~100 m), which would equate to ~10% of total flux attenuation in this depth range. The two flux-feeding taxa considered in this study could account for a substantial proportion of this flux near the base of the euphotic zone. This equated to approximately 6-10% of carbon flux remineralized/10 m. We found that CFA in the shallow twilight zone typically ranged from 500 to 1000 μmol organic C flux remineralized per 10-m vertical depth bin. These estimates were compared to direct measurements of carbon flux attenuation (CFA) made using drifting sediment traps and 238U-234Th disequilibrium. It makes little sense that the screen goes to night intensity when it is up to two hours until what would be considered night here. Using allometric-scaling relationships, we computed the percentage of carbon flux intercepted by flux feeders and suspension feeders. I recon this is more an issue at higher latitudes, as here in Norway, ranging from 58 to 71°N, where the twilight between sunset and civil sunset may last up to two hours. To quantify the potential impact of two flux-feeding zooplankton taxa and the total suspension-feeding zooplankton community, we measured depth-stratified abundances of these organisms during six cruises in the California Current Ecosystem. In contrast to typical suspension-feeding zooplankton, flux-feeding taxa preferentially consume rapidly sinking particles that would otherwise penetrate into the deep ocean. However, the impact of different taxa depends on their feeding mode. ![]() Zooplankton are important consumers of sinking particles in the ocean's twilight zone.
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