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| Author(s): |
Marília Bueno
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | Campinas, SP. |
| Institution: | Universidade Estadual de Campinas (UNICAMP). Instituto de Biologia |
| Defense date: | 2015-07-05 |
| Examining board members: |
Fosca Pedini Pereira Leite;
Setuko Masunari;
Gustavo Muniz Dias;
Marcel Okamoto Tanaka;
André Rinaldo Senna Garraffoni
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| Advisor: | Fosca Pedini Pereira Leite |
| Abstract | |
Articulated calcareous algae are distributed on rocky shores worldwide forming dense mats and harboring rich invertebrate assemblages. Amphipods are dominants and their association with coralline algae was investigated. First, the habitat characterization was done. Algae biomass and amphipods abundance did not differ among seasons, but species composition showed a variable pattern mainly in response to occurrence patterns of the dominant hyalids Apohyale media and Hyale niger. Algae biomass did not vary between degrees of wave exposure, however, more amphipods were found at exposed shores. Tanaids were included and an interesting spatial segregation was observed. Only two species were found, each one associated to a degree of wave exposure. Leptochelia aff. dubia was found at sheltered shores, while Zeuxo coralensis at exposed shores. Coralline mats are wide enough to have distinguished upper and lower zones based on physical (amount of sediment and grain size) and biological (amphipods abundance and species composition) features. After characterizing the habitat, its usage by the amphipods was examined through algae structure (architecture), height on shore and the effect of sediment loads on habitat selection. Interstitial volume was highly variable among the five algae studied and a strong positive relation between interstitial volume and amphipods abundance was observed. Coralline habitat, regardless of the height on shore, was probably the main factor governing habitat selection. Sediment retention at coralline mats was not seasonal and no relation with the amphipods was found. Laboratory experiments corroborate the observed field patterns and added sediment had no effect on habitat selection by the hyalids. The intricate canopy of coralline algae allowed retention, not only of sediment and organic matter, but also of microalgae and meiofauna. This wide array of food items may be important for coralline habitat selection by the amphipods, since they do not feed on coralline itself. In this case, coralline could be an important source of food, allowing the coexistence of amphipods having different feeding habits. Water retention may also play an important role, since habitats are maintained humid during emersion periods (AU) | |