Spatial Responses of Benthic Microbial Communities to Trace Metals Available in Two Contrasting Coastal zones of Northern Chile

Assessments of benthic microbial communities structure and functioning need to be studied in coastal environmental if we are to anticipate the responses of marine ecosystems to future anthropogenic pressures. In light of this, the present study will expect to provide a first insight regarding benthic microbial assemblages and their driving forces, especially Cu and Fe fractioning from two contrasting coastal zones of northern Chile, named Mejilllones Bay (MB) and Off-Loa zone (OL) using 16S rRNA gene sequencing at DNA and RNA (cDNA) to comprehensively explored both structure and potential functions. The findings point out a large fluctuation in microbial communities in terms of taxonomic composition which contributed to the keystone taxa in the network formed two distinct module hubs in both study zones mainly conformed by Calditrichaceae, Flavobacteriaceae, and Sulfurovaceae in the MB whereas Thermoanaerobaculaceae and Unclassified were the representative family members in OL zone. Also, the substantial shifts in the assemblage into the molecular levels were explained by the differential abundance of Nitrosococcaceae and Phycisphaeraceae as active taxa. Further, we provide quantitative evidence supporting the most taxa of each sampling zone strongly associate with specific environmental features linked to both Cu and Fe fractions in MB whereas to the OL zone Fe was the major environmental determinant, though statistically insignificant. However, other closely water depth-related factors like DO, temperature, and salinity also were causal factors. The distinct structure of communities did not correlate with significant functional differences among sampling zones, suggesting that major predicted functions, including transporters, DNA repair, and Signal Transduction allows the microbes to respond to metals and face variable environmental conditions. Thus, the possibly metal tolerant taxa identified in this study could serve as a basis for future monitoring programs of contaminated environments.