Extending the Sub-Sea-Floor Biosphere

• DOI: 10.1126/science.1154545
• Publication Date: 2008-05-22T21:38:55Z
• Authors: Erwan G. Roussel; Marie-Anne Cambon...; Joël Querellou; Barry A. Cragg; Gordon Webster; Daniel Prieur; R. John Parkes
• Keywords: Seabed

Sub-sea-floor sediments may contain two-thirds of Earth's total prokaryotic biomass. However, this has its basis in data extrapolation from ~500-meter to 4-kilometer depths, whereas the deepest documented prokaryotes are only 842 meters. Here, we provide evidence for low concentrations living cells (1626 meters below sea floor), oldest (111 million years old), and potentially hottest (~100 degrees C) marine investigated. These Newfoundland margin also have DNA sequences related thermophilic and/or hyperthermophilic Archaea. form two unique clusters within Pyrococcus Thermococcus genera, suggesting unknown, uncultured groups present deep, hot, (~54 100 C). Sequences anaerobic methane-oxidizing Archaea were present, a deep biosphere partly supported by methane. findings demonstrate that sub-sea-floor extends at least 1600 floor probably deeper, given an upper temperature limit life 113 C increasing thermogenic energy supply with depth.