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The effect of distinct water masses in phytoplankton biomass size classes at the Araçá Bay mouth region (São Sebastião channel - SP) during the summer and winter of 2012

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Author(s):
Ana Luiza de Faria Peres
Total Authors: 1
Document type: Master's Dissertation
Press: Ribeirão Preto.
Institution: Universidade de São Paulo (USP). Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto (PCARP/BC)
Defense date:
Examining board members:
Áurea Maria Ciotti; John Campbell McNamara; Mariana Guenther Soares
Advisor: Áurea Maria Ciotti
Abstract

This study was conducted in São Sebastião Channel and Araçá Bay during summer and winter months in 2012 to analyze the influence of the South Atlantic Central Water (SACW), tides and passage of cold fronts in the phytoplankton size structure, represented by size classes chlorophyll-a concentration of micro, nano and picophytoplankton. Physical and chemical data, as well as chlorophyll-a concentration samples were collected weekly. The São Sebastião Channel was considered a three depth layer system in the Summer, when episodic and variable events of SACW intrusions brought low to moderate nutrients contents. In the Summer, SACW was responsible of the larger nitrate concentration observed, providing a small accumulation of microphytoplankton class biomass, that was equivalent to that of nanophytoplankton. In the Winter, the high silicate concentration was observed in Araçá Bay, suggesting a quickly consumption of other compounds. The overall low nutrient concentration in the Araçá bay suggests a high local consumption. With a homogeneous water column due to mixing, and a probably lower but constant input of nutrients by the Coastal Water mass, the nanophytoplankton predominated over the other size classes and drove the observed higher chlorophyll-a concentration in the Winter. The shallower stations showed a bigger chlorophyll-a concentration variability than the deeper stations, suggesting that both production and removal of chlorophyll-a happen in a smaller temporal scale near shore. (AU)

FAPESP's process: 11/14984-7 - The effect of distinct water masses in phytoplankton biomass size classes at the the Araçá Bay mouth region (São Sebastião channel - SP) during the summer and winter of 2012
Grantee:Ana Luíza de Faria Peres
Support Opportunities: Scholarships in Brazil - Master