Full text
| |
| Author(s): |
Simone Aparecida Dena Silva
Total Authors: 1
|
| Document type: | Master's Dissertation |
| Press: | Campinas, SP. |
| Institution: | Universidade Estadual de Campinas (UNICAMP). Instituto de Biologia |
| Defense date: | 2015-12-14 |
| Examining board members: |
Fosca Pedini Pereira Leite;
Setuko Masunari;
Gustavo Muniz Dias
|
| Advisor: | Fosca Pedini Pereira Leite |
| Abstract | |
Temporal variation, wave exposure and habitat selection are important modulatory factors for animals¿ distribution in the intertidal zone of rocky shores. In this study, we aimed to describe how these factors influence the Tanaidacea assemblage distribution in habitats formed by coralline algae. In addition, we wanted to evaluate the effects of temporal variation and wave exposure in the algal biomass, amount of sediment, diameter and sediment sorting. We collected samples of coralline algae from four rocky shores in Ubatuba (SP, Brazil), being two exposed to wave action (Bravinha and Praia Grande) and two sheltered (Enseada and Itaguá) during the four seasons over one year. The algal samples were collected, dry weight and the characteristics of the sediment retained were measured. Tanaidaceans were identified and their density (per g of algae) was estimated. We also conducted habitat selection experiments with the two most abundant species by offering them microhabitats containing fine, medium and coarse sand. These experiments were done to verify if the species spatial segregation shown in previous studies is caused by a selection of habitats with different grain sizes. The temporal variation influenced the amount of sediment retained in the algae, causing a sediment accumulation during the winter. Sediment sorting was affected by temporal variation and by the local effects of rocky shores, presenting a pattern that varied among the seasons on all rocky shores (except in Praia Grande). The wave exposure gradient was determinant to the diameter of the sand grains trapped by the algae, exposed rocky shores had smaller diameter grains, while sheltered rocky shores had bigger diameter. These results were contrary to the expectation, according to the literature. The amount of organic matter and algal biomass varied according to rocky shores characteristics. Bravinha showed higher biomass and, together with Itaguá, a larger amount of organic matter; these local variations are due to differences in the algae bed structure and to large amounts of Mytilidae in Bravinha and sponges in Itaguá. The Tanaidacea assemblage in coralline algae was composed by two species: Leptochelia aff. dubia and Zeuxo coralensis. The wave exposure was determinant on the distribution of L. aff. dubia, which density was higher in sheltered shores, corroborating the initial hypothesis and the pattern already demonstrated in the literature. The Z. coralensis population density varied according to the seasons and the local characteristics of rocky shores, being higher in Praia Grande and Bravinha (both exposed rocky shores), especially during the spring and summer. None of these species showed preference for microhabitats with different grain size, but they were able to manipulate and build tubes with those existing grains. Thus, the habitat occupied is not explained by the species ability to manipulate different grain sizes (AU) | |
| FAPESP's process: | 12/21465-9 - MODULATORS FACTORS OF ASSEMBLY TANAIDACEA(CRUSTACEA) ASSOCIATED TO CORALLINE ALGAE ON ROCKY SHORES NORTHERN IN COAST OF SÃO PAULO |
| Grantee: | Simone Aparecida Dena Silva |
| Support Opportunities: | Scholarships in Brazil - Master |