Also, regarding subsea volacanic
eruptions — a
volcanic eruption involves release
of magma at several thousand degrees C plus superheated gases — when that hits cold sea water you are going to have a very violent and explosive change
of form from lquid water to steam
combined with the release
of dissolved gases (mostly CO2)-- I am not sure what laws
of Chemistry and Physics you are looking at, but I would suggest that that those bubbles and heated gases and water will rise to to the surface very quickly and have a major local
effect on any nearby ice.