Submarine Shallow-Water Fluid Emissions and Their Geomicrobiological Imprint: A Global Overview

Abstract

Submarine fluids emissions in the form of geothermal vents are widespread in a variety of geological settings ranging from volcanic to tectonically active areas. This overview aims to describe representative examples of submarine vents in shallow-water areas around the globe. The areas described include: Iceland, Azores, Mediterranean Sea (Italy and Greece), Caribbean, Baja California, Japan, Papua, New Zealand, Taiwan. Common and divergent characteristics in terms of origin and geochemistry of the emitted fluids and their impact on the indigenous organisms and the surrounding environment have been identified. In the hottest vents seawater concentration is common as well as some water vapor phase separation. Carbon dioxide is the most common gas often associated with compounds of sulfur and methane. In several vents precipitation of minerals can be identified in the surrounding sediments. The analyses of the microbial communities often revealed putative chemoautotrophs, with Campylobacteria abundantly present at many vents where reduced sulfur compounds are available. The techniques that can be used for the detection and quantification of underwater vents are also described, including geophysical and geochemical tools. Finally, the main geobiological effects due to the presence of the hydrothermal activity and the induced changes in water chemistry are assessed.

Unveiling the Inherent Physical-Chemical Dynamics: Direct Measurements of Hydrothermal Fluid Flow, Heat, and Nutrient Outflow at the Tagoro Submarine Volcano (Canary Islands, Spain)

“…The estimate of this discharge is higher than 280.845.000 m 3 y − 1 , exceeding twice the hydrothermal discharge reported for several areas of Milos together with 106.500.000 m 3 y − 1 (Megalovasilis, 2020). This flux is also equivalent to 35-times the volume discharged at Kraternaya Bay (22.000 m 3 /day) located on the Kurile archipelago in the Western Pacific (Caramanna et al, 2021).…”

Seeps and Tectonic Structure of the Hydrothermal System of the Panarea Volcanic Complex (Aeolian Islands, Tyrrhenian Sea)

“…These cyclical explosions could produce serious dangers to people and ecosystems [22,[56][57][58] as a consequence of slides, earthquakes, tsunamis [22,59,60] or modifications of water column properties changing the biota communities or dead zone formation [61][62][63].…”

Shallow Sea Gas Manifestations in the Aegean Sea (Greece) as Natural Analogs to Study Ocean Acidification: First Catalog and Geochemical Characterization

“…Even though the impact of gases on marine flora and fauna was not investigated in the current study, it shouldn't be disregarded. Various researchers (e.g., Boatta et al, 2013;Price and Giovannelli, 2017;Aiuppa et al, 2021;Caramanna et al, 2021) have already highlighted that shallow marine vents can provide us with an accessible and economic way to investigate the effects of CO 2 on the whole marine ecosystems. In addition to this, parameters like the presence of light, wave action, tides, the input of meteoric water, salinity variations, etc., can significantly influence the geochemistry of the vents and the microbial diversity and distribution (Giovannelli and Price, 2018).…”