CO2 Degassing From Hydrothermal Vents In Aegean Sea

The Kolumbo lies about 8 km northeast of Cape Kolumbo, Santorini Island and I an active underwater volcano in the Aegean Sea. This is one of the largest underwater volcanoes in the world but has not seen any major eruptions for a long time. credit top 10 list

Hydrothermal vents in the crater of Kolumbo submarine volcano (Aegean Sea) are discharging carbon dioxide together with fluids at temperatures up to 220 degrees C. The gas is dissolving into seawater close to the bottom, leading to significant acidification of the water inside the crater with pH levels down to 5.0.

This water is trapped within the bowl-shaped crater because of its increased density associated with high carbon dioxide contents. Lack of abundant macrofauna at the Kolumbo hydrothermal vents and the occurrence of carbonate-poor sediment in the crater appear to be consequences of this local anomaly in ocean acidification.

These sites provide important opportunities to study the composition of gases released to the ocean and their contribution to the global carbon flux. Build-up of CO2-rich water in the bowl-shaped crater of Kolumbo may be producing hazardous conditions analogous to some African volcanic lakes (Monoun and Nyos) where overturn of gas-rich bottom waters led to abrupt releases of CO2 at the surface.

Water samples collected near the floor of Kolumbo volcano released gas when they were brought to the surface and exposed to atmospheric pressure. A minimum estimate of 1.4 by 105 cubic meters of excess CO2 may exist in the bottom 10 meters of the Kolumbo crater.