Polycystinea radiolaria 14 Protista 8 sediment trap 8 species richness 8 Nassellaria 6 geographical distribution 6 taxonomy 6 vertical distribution 6 Pacific Ocean 4 Radiolaria 4 Radiolaria (protozoans) 4 Rio de la Plata 4 South America 4 World Ocean 4 World ocean 4 abundance 4 dissolution 4 estuary 4 new record 4 new species 4 plankton 4 species diversity 4 surficial sediment 4 water column 4 Abundance 2 Biodiversity 2 Chlorophyll 2 Classification 2 Dissolution rates 2