Mesozooplankton biomass and grazing in the Costa Rica Dome: amplifying variability through the plankton food web.

摘要: We investigated standing stocks and grazing rates of mesozooplankton assemblages in the Costa Rica Dome (CRD), an open-ocean upwelling ecosystem eastern tropical Pacific. While phytoplankton biomass CRD is dominated by picophytoplankton (<2-µm cells) with especially high concentrations Synechococcus spp., we found (∼5 g dry weight m-2) impact (12-50% integrated water column chlorophyll a), indicative efficient food web transfer from primary producers to higher levels. In contrast relative uniformity water-column a biomass, variability herbivory was substantial, lower central dome region areas offset center. were unrelated total phytoplankton, correlations cyanobacteria (negative) biogenic SiO2 production (positive) suggest that partitioning among sizes contributes observed metrics. propose advection upwelled waters away center accompanied changes composition rates, reflecting small within producers. Small community resulting large trophic level dynamics effectively amplified through web.