Petit-spot volcanoes involve deepest known submarine hydrothermal activity, may release methane

Underwater volcanoes on the Earth's crust are active contributors of many different elements to the oceanic environment. Hence, they play an important role in biogeochemical and chemosynthetic cycles of the ocean. Although there have been many studies on high-temperature hydrothermal systems in the mid-ocean ridge—a series of underwater volcanoes that trace the edges of the different oceanic plates—there is little information on low-temperature hydrothermal systems in other volcanoes, such as "petit-spot" volcanoes.