Enigmatic Archaeal and Eukaryotic Life at Hydrothermal Vents and in Marine Subsurface Sediments

Abstract

This chapter is intended as a brief introduction on specific, novel aspects of archaeal and eukaryotic biodiversity in two extreme marine environments, hydrothermal vents and deep subsurface sediments: deeply-branching, uncultured archaea occurring in both environments that in some cases do not fit into the well-established crenarchaeota-euryarchaeota dichotomy; the partial overlap in the archaeal community structure of hydrothermal vents and deep subsurface sediments; new developments to decode the physiology and carbon sources of subsurface and vent archaea; and the unexpected diversity of enigmatic protists at hydrothermal vents.