Taxonomia, ecologia e química da esponja Darwinella sp. (Porifera: Dendroceratida) de Arraial do Cabo, RJ

Abstract

The genus Darwinella was rare in the region of Arraial do Cabo (RJ) in the late 1980s, but is now commonly found growing on rocky shores. However, there are still doubts about the taxonomic identification of the species recorded in the region. Furthermore, the studies carried out with Darwinella in the region have shown a great diversity of secondary metabolites, which directly influences the spatial and trophic structure of the benthic communities. Thus, the objective of the present work was to deepen the knowledge about taxonomic, ecological and chemical aspects of the sponge Darwinella sp. that occurs in the Arraial do Cabo region. The first chapter was entitled "Taxonomy of the sponge Darwinella sp. (Porifera: Dendroceratida) from the Marine Extractive Reserve of Arraial do Cabo, RJ"; Chapter 2 was entitled "Effect of temperature on the growth of the sponge Darwinella sp. (Porifera: Dendroceratida) from Arraial do Cabo, RJ, Brazil". And chapter 3 was entitled "Study of the variation of the chemical profile of the sponge Darwinella sp. (Porifera: Dendroceratida) facing ecological relationships of interspecific competitions in the region of Arraial do Cabo". In the first chapter, the morphological structures present in the sponge were compared to other species of the same genus described in the literature. The results showed that the sponge present in the region is distinct from other species of the genus. However, due to the morphological plasticity of these organisms and the scarcity of morphological characters of this genus, for confirmation of a possible new species it is necessary that additional identification tools, such as molecular taxonomy, be used. In chapter 2, we also investigated the possible effect of water temperature variation on sponge growth at two different points in Arraial do Cabo Bay. No significant difference was observed between growth and temperature (p>0.05), suggesting that other factors not addressed in this study would explain these differences. In chapter 3, the chemical profile of the sponge was also evaluated when in direct (boundary) and indirect (internal part) interaction with three potential competitors, the invading coral Tubastraea coccinea, the antozoan Palythoa caribaeorum, and the turf algae. The results show the existence of spatially arranged chemical variability in different parts of the Darwinella sp. tissue, and also that the chemical profile of the sponge is able to vary according to the identity of the competitors sharing the consolidated substrate with the sponge.