**8. Conclusions**

In the Peixe Lagoon, the benthic diatoms were present in high diversity. Among the attributes of the community, the taxonomic composition best responded to the environmental variables. The quantitative attributes did not show significant relationships. The connection with the ocean, salinity, rainfall, wind action, and temperature were strongly related to the spatial and seasonal variation of the composition of the diatom community in this lagoon system. These organisms substantiate their use as indicators of environmental variations, mainly regarding salinity and temperature in subtropical coastal systems.
