Contribution to the knowledge of environmental conditions in the shallow reefs of northern Cuba using indicator microorganisms

Coral reefs are a high priority for conservation due to their ecological importance, their state of global degradation, and their significance in the context of climate change. Given the anthropogenic pressures affecting these ecosystems, the use of indicator microorganisms is an ideal way to assess the environmental conditions in which they thrive. Between July and September 2023, a survey called “Bojeo a Cuba” was conducted on the Cuban insular shelf to assess the health of the surrounding shallow reefs. Twelve reefs off the north coast were sampled, with 32 water and sediment samples collected in the veril biotope (between 5 and 18 m depth). In general, oligomesotrophic to mesotrophic transition conditions prevailed in the waters surrounding the shallow reef ecosystems of northern Cuba in 2023, as indicated by bacterial and phytoplankton concentrations. Potentially harmful dinoflagellate species were detected in reefs such as Santa Lucía-Camagüey, Cayo Coco, Cayo Francés, Puerto Padre, and Vita, while high concentrations of cyanobacteria were found in Bahía Honda, Isabela de Sagua, and Cayo Francés. The FoRAM Index values, between 2 and 4, suggest a potential increase in organic matter in the waters adjacent to the reefs of Santa Lucía-Pinar del Río, Bahía Honda, Cayo Coco, and Vita. The analysis based on the response of water quality indicator microorganisms suggests an alteration of environmental conditions in the waters adjacent to the reefs of Santa Lucía-Pinar del Río (SLPR), Bahía Honda (BAHO), Cayo Francés (CAFR), and Cayo Coco (CACO), which could compromise the health of these ecosystems.