Shallow hydrothermal vents in the southern Tyrrhenian Sea

Shallow hydrothermal systems represent particularly suitable fields for studying the interactions between fluids and microorganisms inhabiting extreme environments. Coastal zones of the southern Tyrrhenian Sea are home to shallow hydrothermal systems, related to both active and extinct volcanism, located in the Flegrean area, at Cape Palinuro and around the Eolian Islands. A great diversity of Archaea and Bacteria has been reported at shallow hydrothermal vents, where they are key elements in ecosystem functioning. When compared with deep-sea locations, photosynthetic microorganisms appear to be the main characteristic of shallow hydrothermal vents, where both light and hydrothermal energy support a complex microbial community displaying primary productivity (phototrophic and chemotrophic) of mixed origin. Viriobenthos abundances are low compared with other shallow marine systems, suggesting that viruses are less tolerant than prokaryotes of high temperatures and consequently are believed to have a low impact on prokaryotic abundance and biodiversity. Microorganisms from shallow hydrothermal vents represent an almost unexploited resource for thermostable enzymes and biomolecules potentially valuable in biotechnology.