Molecular analyses of the sediment of the 11000-m deep Mariana Trench

Abstract

We have obtained sediment samples from the world's deepest sea-bottom, the Mariana Trench challenger point at a depth of 10898m, using the new unmanned submersible Kaiko. DNA was extracted from the sediment, and DNA fragments encoding several prokaryotic ribosomal RNA small-subunit sequences and pressure-regulated gene clusters, typically identified in deep-sea adapted bacteria, were amplified by the polymerase chain reaction. From the sequencing results, at least two kinds of bacterial 16S rR-NAs closely related to those of the genus Pseudomonas and deep-sea adapted marine bacteria, and archaeal 16S rRNAs related to that of a planktonic marine archaeon were identified. The sequences of the amplified pressure-regulated clusters were more similar to those of deep-sea barophilic bacteria than those of barotolerant bacteria. These results suggest that deep-sea adapted barophilic bacteria, planktonic marine archaea, and some of the world's most wide-spread bacteria (the genus Pseudomonas) coexist on the world's deepest sea-bottom. © Springer-Verlag 1997.