Variação espaco-temporal da comunidade bentônica de costões rochosos do infralitoral de Arraial do Cabo (RJ), Brasil

Abstract

Rocky shore benthic communities are complex and heterogeneous ecosystems characterized by ecological interactions between the biota and the environment. The present work analyzed the distribution and the relative abundance of the infralittoral benthic communities along different environmental gradients in Arraial do Cabo (RJ). In order to identify benthic variations (spatial, vertical and temporal), quarterly photoquadrat samplings were carried out from July 2017 to June 2019 at six rocky shores: four sheltered and two exposed. The analyses indicate that the most representative categories of morphofunctional groups were: epilithic algal matrix (EAM), articulated coralline algae (ACA) and macroalgae (MA). The rocky shores of Arraial do Cabo presents different benthic community composition, depending on the location (exposed or sheltered area), depth, and season. The presence of hard corals and zoanthids only in the sheltered area shows the contrast between the tropical and the subtropicaltemperate characterized areas. The results show an inverse trend for MA cover and the presence of the other algae groups (EAM and ACA). This trend is more evident during summer and spring, possibly associated with upwelling events and the higher sunlight and dissolved nutrients during these seasons. The understanding of these distribution patterns advances in the knowledge of the benthic community structure at Arraial do Cabo, an important region in the context of marine conservation, facing growing impacts from diverse fisheries, and nautical/underwater tourism. This work presented the first temporal evaluation of the benthic community of the different hydrodynamic domains of Arraial do Cabo. Thus, it is recommended to continue the monitoring, improving sampling effort at the exposed area, seeking a future analyzes improvement regarding the interannual behavior of the local benthic composition.