Diversity and Variation of Epiphytic Diatoms on Ruppia maritima L., Related to Anthropogenic Impact in an Estuary in Southern Brazil

Knowledge about the diversity and spatiotemporal variability of epiphytic diatom communities in estuarine meadows has great relevance for coastal ecology and, thus, contributes to understanding impact natural anthropogenic changes on seagrass meadows. The community diatoms Ruppia maritima L. was investigated two environments with different levels nutrient loads. Both impacted non-impacted had similar conditions terms water depth, temperature transparency but distinct loads salinity ranges. A total 159 taxa were found leaves during monitoring period, including freshwater (30.8%), marine (25.1%), brackish (9.4%) cosmopolitan (8.8%) taxa. most abundant species C. placentula, T. tabulata, M. pumila fasciculata, addition A. tenuissimus, adhaerens moniliformis. Although present both sites, placentula tabulata dominant site. We that 32% exclusive site, 23% site 45% common sites. study sites showed marked differences attributes; i.e., higher richness, equitability lower dominance which is distant from sources domestic industrial sewage low concentrations dissolved N P values sediment organic matter. Nutrient concentration main factors behind spatial temporal structure when all other environmental variables (water temperature, host plant). influence site-dependent. This revealed high richness Patos Lagoon estuary (PLE) heterogeneity communities, it shows potential studies assessment quality meadow habitats.