Microbial Communities Surrounding an Underwater Volcano Near the Island of El Hierro (Canary Islands)

Underwater hydrothermal systems release nutrient-rich fluids that are favorable for microbial activity. This allows the growth of a plethora of microorganisms that can be found inhabiting hydrothermal plumes, metalliferous sediments, or forming dense microbial biofilms or mats on the surrounding of the vents. Most of the current knowledge on the microbiology associated with underwater volcanic activity comes from the study of deep-sea hydrothermal vents. However, much less is known about shallow underwater hydrothermal systems. The submarine volcanic eruption that took place near El Hierro (Canary Islands) in October 2011 and gave rise to the Tagoro volcano, located only 1.8 km from land and approximately 89 m below the sea surface, provided a rare occasion to study almost in real time the microbiology associated with an underwater eruptive process, from its birth to the current degassing state, allowing investigations of its effects on the surrounding pelagic and benthic communities. In this chapter, we summarize what is known 10 years after the formation of the Tagoro submarine volcano, and we discuss what questions should be pursued in order to foster our knowledge of the microbiology associated with this volcano and its surrounding waters.