Variabilidade da infauna adjacente a estruturas rochosas na plataforma rasa do litoral do Paraná, Brasil
Lorenzi, LucianoA. Borzone, Carlos
Ocean rocky formations are known as islands. When islands become completely submerged, they are called stone slabs. Like reefs, these formations alter the flux of water produced by the waves, which in turn interacts with the adjacent sediment, altering the sediment and its undulation marks. The alterations caused by the interaction between the waves and emerged or submerged rigid structures can potentially alter the composition and the distributional patterns of the infauna of the adjacent, unconsolidated substrate. In order to evaluate the strength of these alterations, we sampled the infauna and the sediment adjacent to two ocean structures, one emerged and one submerged. Collecting was performed in winter and summer, while discriminating between the faces of the structures, the distances from them, and the troughs and crests of ripple marks. The granulometric characteristics of the sediments and the dimensions of the undulation marks differed in regards to the orientation of and the distance from the structures. Infaunal associations showed differences that can be explained by the sedimentation patterns. However, there were no differences in sediment characteristics and composition of the infauna when troughs and crests were compared. The waves interacted most intensely with the submerged structure, where the sediment showed larger grains next to the undulation marks, what resulted in a more pronounced differentiation of the infauna.
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