A:Sometimes,an underwater eruption is so big, that it produces a megaplume of warm, mineral water, which eventually rises to the surface because it is lighter. A few research vessels have actually reported that they had a direct experience of an underwater erupting volcano. Researchers on board described that bubbles of gas and steam appeared at the surface,aswell as an increase in water temperature and so much volcanic material was presented, that the water turned cloudy. In terms of general rise in oceanic water temperature, the heat released at mid-ocean ridges is not significant, compared with the sun's input of heat.