Spatial-temporal distribution of Olivella minuta (LINK, 1807) (Mollusca, Gastropod, Olividae) in the intertidal zone of Araçá Bay, southeastern coast of São Paulo state, Brazil

Author(s)

Rita Monteiro Camargo

• Document type: Master's Dissertation
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Instituto Oceanográfico (IO/DIDC)
• Defense date: 2013-02-07

Examining board members

Alexander Turra; Gustavo Muniz Dias; Fabiane Gallucci

• Advisor: Alexander Turra

Abstract

The objective of this study was to analyze the temporal and spatial distribution of one of the species representative of the macrofauna of sheltered sandy beaches. Measurements using different scales (mesoscale, microscale and time scale) were utilized. The gastropod Olivella minuta, which is abundant in the intertidal region of Baía do Araçá, was used for these analyses. For the mesoscale study, 16 stations were determined within the intertidal region (July/2009) and, in each station, 8 biological samples and 3 samples of sediment were collected. Some abiotic factors (calcium carbonate, organic matter and selection coefficient) had a negative influence on the abundance of the gastropod, while relationship between the O. minuta and other species of the macrofauna were not evident. In a microscale study of tidal ponds (meters) and ripple marks (centimeters), it was observed that, in a centimeter scale, the gastropod was more abundant in places where there was more water in the sediment, whereas in a meter scale the abundance didn\'t vary in or out of the ponds. In a temporal scale, monthly fluctuations of the O. minuta population\'s density were observed, with reduction/absence of individuals between February and March, which suggests that migration and mortality occurred. This study showed that the distribution of O. minuta is influenced by different factors which act in different scales. (AU)

• FAPESP's process: 10/01426-3 - Spatio-temporal distribution of Olivella minuta (Link, 1807)(Mollusca, Gastropoda, Olividae) in the intertidal zone of Araçá Bay, São Sebastião, northern coast of São Paulo State
• Grantee: Rita Monteiro Camargo
• Support type: Scholarships in Brazil - Master