copepods crustacean 6 Atlantic Ocean 4 Atlantic Ocean (Southwest) 4 Brazil-Malvinas Confluence 4 Southwestern Atlantic 4 abundance 4 biomass 4 chlorophyll 4 community structure 4 normalized biomass size spectra 4 population density 4 population distribution 4 size structure 4 summer 4 trophic level 4 upper ocean 4 zooplankton 4 cladocerans 3 predation 3 Bivalvia 2 Copepoda 2 Dreissena 2 Dreissena polymorpha 2 Limnoperna fortunei 2 Mollusca 2 Parana River 2 bivalve 2 clearance rate 2 ecological impact 2