- CoDL Microbes in mud volcanoes
Mud volcanoes are commonly called “windows to the deep biosphere”, because they represent surface expressions of a rapid upward transport of subsurface sediments of as deep as a few kilometers. On land and in the sea we know of tens of thousands of active mud volcanoes, which expel muds, anoxic fluids, gases, and hydrocarbons. The first microbiological investigations of submarine mud volcanoes have indicated that the subsurface muds are inhabited by typical subsurface microorganisms (e.g., marine benthic crenarchaeal groups, Cytophaga/Flavobacteria groups), but that they are overgrown by anaerobic and aerobic methanotrophs after exposure to electron acceptors such as sulfate and oxygen. However, the time scales at which this succession occurs, the fate of the original deep biosphere communities and the potential for their dispersal remain unknown. In 2009 and 2010, we had the opportunity to sample transects across very recent mud flows at the Håkon Mosby Mud Volcano (HMMV), including a major flow from a recent eruption. We propose to analyze samples of different sediment depths, spatial and temporal distances from the fresh mud flow for both their bacterial and archaeal communities to improve knowledge on the composition, persistence, and dispersal of deep biosphere communities which are exposed to surface environments.