Vírus-Bacteria Dynamics In The Coral Siderastrea Stellata

Coral reef systems constitute reservoirs of extensive genomic diversity sustaining ecosystems characterized by high levels of biodiversity and primary productivity. Nevertheless, anthropogenic activities have markedly compromised coral reef health. Alterations in the physicochemical properties of seawater have direct repercussions on marine microsymbiotic associations, including diverse marine taxa. Among the most critical microsymbiosis in reef environments are the associations between cnidarians and dinoflagellates (zooxanthellae), in conjunction with diverse bacterial communities. In addition, viruses have been documented in association with prokaryotic - eukaryotic and coral organisms, contributing to modulation of coral health and exerting control over specific bacterial populations. Our study aimed to quantify bacterial and viral abundances present in the coral Siderastrea stellata at two locations - Porcos Island and Forno Beach, both situated in Arraial do Cabo, Rio de Janeiro, Brazil. Concurrently, analyses seawater physicochemical parameters at depths (5m and 15m) to determine their potential influence on virus-bacteria dynamics. Our findings revealed that temperature and nutrient concentrations exhibited variation with depth. Total bacterial abundance exceeded that of metabolically active bacteria and was positively correlated with dissolved organic carbon concentrations. The abundance of metabolically active bacteria appeared to be associated with ammonium levels and was comparatively higher at Forno Beach. Although marine viruses were detected in coral samples, the absence of viral genome sequencing precluded definitive taxonomic classification. These results underscore the necessity for further investigations incorporating additional environmental parameters and metagenomic approaches to elucidate the complex interactions among viruses, bacteria, and coral hosts within reef ecosystems.