Feast and famine — microbial life in the deep-sea bed

Abstract

The seabed is a diverse environment that ranges from the desert-like deep seafloor to the rich oases that are present at seeps, vents, and food falls such as whales, wood or kelp. As well as the sedimentation of organic material from above, geological processes transport chemical energy--hydrogen, methane, hydrogen sulphide and iron--to the seafloor from the subsurface below, which provides a significant proportion of the deep-sea energy. At the sites on the seafloor where chemical energy is delivered, rich and diverse microbial communities thrive. However, most subsurface microorganisms live in conditions of extreme energy limitation, with mean generation times of up to thousands of years. Even in the most remote subsurface habitats, temperature rather than energy seems to set the ultimate limit for life, and in the deep biosphere, where energy is most depleted, life might even be based on the cleavage of water by natural radioisotopes. Here, we review microbial biodiversity and function in these intriguing environments.

Optimization of Lipase production from a novel strainThalassospira permensisM35-15 using Response Surface Methodology

“…17 The presence of lipolytic bacteria in the sediment could be explained by some kinds of fatty acids deposited on the sea floor. 18 The strain exhibited significant lipolytic activity and used in the optimization study was separated from sediment sample (¡1523m), which collected from South Atlantic (W14.35 , S14.04 ). It was identified as Thalassospira permensis M35-15 based on 16S rRNA gene sequence analysis (data not shown).…”

Comparative genomics reveals a deep-sea sediment-adapted life style of Pseudoalteromonas sp. SM9913

“…It is estimated that around 13% of total global bacteria live in the upper 10 cm of deep-sea sediments (Turley, 2000;Schippers et al, 2005). In most deep-sea sediments, no light is present, temperatures are close to freezing (-1 1C to 4 1C), the pressure is very high and oxygen concentrations are usually very low compared with surface seawater (Jørgensen and Boetius, 2007).…”

“…Deep-sea sediment is a dynamic geo-and biosphere that hosts rich microbial communities (Whitman et al, 1998;Jørgensen and Boetius, 2007). It is estimated that around 13% of total global bacteria live in the upper 10 cm of deep-sea sediments (Turley, 2000;Schippers et al, 2005).…”

“…The deep-sea floor accounts for almost 60% of the Earth's surface (Brunnegarda et al, 2004), most of which is covered with fine-grained sediments (Jørgensen and Boetius, 2007). Deep-sea sediment is a dynamic geo-and biosphere that hosts rich microbial communities (Whitman et al, 1998;Jørgensen and Boetius, 2007).…”

Comparison of the microbial community composition of pristine rock cores and technical influenced well fluids from the Ketzin pilot site for CO2 storage

“…Biosphere (Brockman et al 1992;Fry et al 1997;Whitman et al 1998;Aldén et al 2001;Fredrickson and Balkwill 2006;Goldscheider et al 2006;Jørgensen and Boetius 2007), therefore in the Exter Formation rock cores, where the carbon concentration is particularly low, the number of microorganisms is comparatively low.…”