Sass, Henrik ORCID: https://orcid.org/0000-0001-8740-4224 and Parkes, Ronald John 2016. Deep sub-surface. Reference Module in Life Sciences, Elsevier, (10.1016/B978-012373944-5.00275-3) |
Abstract
Marine sediments cover ~70% of the Earth’s surface and contain the largest reservoir of organic matter and significant amounts of fossil fuels. They have recently been estimated to be a major microbial habitat to at least 1 km depth, containing between 1 and 30% of global biomass. Prokaryotic cells, which are ubiquitous in these sediments, utilize organic matter for energy and generally decrease with depth, as remaining organic matter is more recalcitrant. Remarkably, even ancient organic matter is apparently still used, but on geological timescales (hundreds of millions of years) and enabling extremely slow growth rates. In addition, there is marked subsurface stimulation of populations at depths where there are additional energy sources, such as sulfate–methane interfaces, high organic matter layers, fluid flow within rock basement, and upward diffusion of compounds from deep, hot thermogenic reactions. However, there is also overlap between deep biosphere and thermogenic processes and prokaryotic reactions may play a wider role in deep geochemical processes than previously considered, including deep gas formation. Biodiversity is high with some bacterial and archaeal groups being unique to subseafloor sediments, and there are “hot spot” deep biosphere habitats. Significance includes climate, fossil fuels, origin of life, and life on other planets.
Item Type: | Book Section |
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Date Type: | Published Online |
Status: | Published |
Schools: | Earth and Environmental Sciences |
Publisher: | Elsevier |
ISBN: | 9780128096338 |
Last Modified: | 20 Nov 2022 07:20 |
URI: | https://orca.cardiff.ac.uk/id/eprint/97388 |
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