Ocorrência e coexistência de cianobactérias diazotróficas no Canal de São Sebastião-SP com o aumento da pluviosidade

Phytoplankton composition from Araçá Bay and São Sebastião Channel, São Paulo, Brazil

“…Slicks of the genus Trichodesmium are commonly observed in surface waters of the Brazilian Current (Detoni et al 2016) or in inner shelf waters (< 50 m) during the summer (Brandini et al 1989). The occurrences could be linked to the relatively low nitrogen input from the continent, as the observations took place during a dry period (Tocci 2016), favoring the growth of diazotrophic cyanobacteria. However, at least for Trichodesmium, the advection of waters from offshore by mesoscale winds (Castro Filho & Mirada 1998) could be a source of these organisms for the coast.…”

“…Three water samples were combined to represent AB and SSC to increase the representativeness of the occurring taxa analysis. AB samples refer to the combination of three independent stations located at isobaths between 1.5 and 2 m, while SSC refers to three successive deployments of the Van Dorn bottle (Tocci, 2016). The composite samples were further concentrated (2 L to about 100 mL) by reverse filtration with a 5 μm nylon mesh and preserved with formaldehyde neutralized in hexamethylenetetramine (0.4 %).…”

“…More recent analyses of changes in chlorophyll concentration fractionated by size classes (Giannini & Ciotti 2016) and main taxonomic groups (Ciotti et al 2018a) derived from efforts during the Araçá Thematic FAPESP project (https://biota-araca.org/index.html), conducted from September 2013 to August 2014 and showed the importance of diatoms when phytoplankton biomass increased. The present study is also derived from the Araçá Project phytoplankton dataset (Tocci 2016) and focuses on detailed taxonomic descriptions of phytoplankton in Araçá Bay and SSC, using light microscopy. The main objective is to update the phytoplankton taxa for this region, report their relative occurrence frequencies, and describe differences between the species found in Araçá Bay and the adjacent waters in the São Sebastião channel.…”