Biology subjects

Amalfitano, S.

Publications and source records attributed to Amalfitano, S..

3 recordsLinked to original sources

bioRxiv2025

Ancient Roman saltworks drive the present-day microbial community profiles in a coastal aquifer

Historical salinization from ancient saltworks can leave a long-lasting imprint on coastal aquifers, but its impacts on subsurface microbial communities and ecosystem functioning remain poorly understood. This study examined how legacy salt inputs from Roman saltworks in the Tiber River delta (Fiumicino, Italy) continue to shape present-day groundwater chemistry, microbial community structure, and metabolic potential of the coastal aquifer. We analyzed groundwater samples from non-salinized and salinized units of the same aquifer using integrated hydrogeochemical characterization, flow cytometry, 16S rRNA gene amplicon sequencing, and functional metabolic assays. Salinized samples exhibited elevated chloride, bromide, sodium, and sulfate concentrations, with distinctive ionic ratios (Br/Sr, Cl/K, SO/Ca) indicating dissolution of salt deposits rather than contemporary seawater intrusion. Salinization reduced the microbial diversity and shifted communities from diverse freshwater-adapted families toward an abundant halotolerant assemblage dominated by Campylobacterota (families Sulfurimonadaceae and Sulfurovaceae). Functional annotation suggested broadly conserved potentials for carbon, nitrogen, and sulfur cycling. However, the Biolog assays revealed higher heterotrophic respiration and carbon substrate use but lower functional diversity in salinized samples, with particularly enhanced polymer degradation. Ordination analyses showed a clear separation of aquifer units along the salinization gradient, with coordinated chemical and microbial vectors indicating alternative ecosystem states sustained by millennia-old anthropogenic salt inputs. Our findings showed that ancient saltworks can drive persistent hydrogeochemical alteration, select specialized halotolerant microbiomes, and reconfigure carbon and nutrient processing while maintaining core biogeochemical functions, with critical implications for coastal groundwater management strategies.

microbiology↗

bioRxiv2025

Constructed wetlands for aquaculture wastewater treatment: insights on the structural and functional shifts of the aquatic microbial community

Aquaculture practices generate nutrient-rich effluents with associated microbiological hazards, such as pathogens and antimicrobial resistance genes (ARGs). Despite their growing popularity as nature-based solutions, little is known about how constructed wetlands (CWs) affect the dynamics of microbial communities at the field scale. By combining flow cytometry, 16S rRNA gene sequencing, shotgun metagenomics, and metabolic potential assays, we investigated the structural and functional responses of the aquatic microbial community following the recurrent exposure to CW-treated effluents from an intensive marine fish farm (Orbetello lagoon, Italy). While the CW promoted abundant, metabolically active, and functionally redundant microbial communities, the phylogenetic composition diverged primarily between water and sediments. Microbial profiles in CW outlet waters converged towards those of the lagoon baselines, suggesting gradual ecological recovery. The CW attenuated the occurrence of potential pathogens (e.g., Francisella spp., Campylobacter spp.) and limited ARG dissemination, though sediments remained reservoirs of microbial and genetic signatures. Functional profiles, dominated by chemoheterotrophy, denitrification, and sulfur respiration, remained stable across environments, reflecting microbial resilience. Our results highlight CWs as effective, field-proven solutions to mitigate aquaculture wastewater impacts while preserving core ecosystem services.

ecology↗

bioRxiv2018

Water quality and microbial load: a double-threshold identification procedure intended for space applications

During longer-lasting future space missions, water renewal by ground-loaded supplies will become increasingly expensive and unmanageable for months. Space exploration by self-sufficient space-crafts is thus demanding the development of culture-independent microbiological methods for in-flight water monitoring to counteract possible contamination risks. In this study, we aimed at evaluating microbial load data assessed by selected techniques with current or promising perspectives in space applications (i.e., HPC, ATP-metry, qPCR, flow cytometry), through the analysis of water sources with constitutively different contamination levels (i.e., chlorinated and unchlorinated tap waters, groundwaters, river waters, wastewaters). Using a data-driven double-threshold identification procedure, we identified and presented new alternative standards of water quality based on the assessment of the total microbial load. Our approach is suitable to provide an immediate alert of microbial load peaks, thus enhancing the crew responsiveness in case of unexpected events due to water contamination and treatment failure. Finally, the backbone dataset could help in managing water quality and monitoring issues for both space and Earth-based applications.

microbiology↗