The Guaymas Basin - A hot spot for hydrothermal generation and anaerobic microbial degradation of hydrocarbons

Guaymas Basin is a young marginal rift basin in the Gulf of California characterized by active seafloor spreading, rapid deposition of organic-rich sediments, and steep geothermal gradients where sedimentary organic material of photosynthetic origin turns into hydrocarbons -potential microbial substrates. After introducing the sources of hydrocarbons in the subsurface, this short overview discusses the phylogenetic diversity, temperature range and occurrence patterns of novel alkane-oxidizing bacteria and archaea in the hydrothermal sediments of Guaymas Basin. Many of these alkane-degrading specialists function as syntrophic consortia, where sulfate-reducing bacteria accept electron from methane-or alkane-oxidizing archaea. As a source of metagenomes, enrich-ments, and cultures of these methodologically and conceptually challenging microorganisms, Guaymas Basin stands out as an indispensable field site that has consistently catalyzed new insights into the microbiology of anaerobic hydrocarbon oxidation and assimilation.