In:
Proceedings of the National Academy of Sciences, Proceedings of the National Academy of Sciences, Vol. 103, No. 38 ( 2006-09-19), p. 14164-14169
Abstract:
Increasing levels of CO 2 in the atmosphere are expected to cause climatic change with negative effects on the earth's ecosystems and human society. Consequently, a variety of CO 2 disposal options are discussed, including injection into the deep ocean. Because the dissolution of CO 2 in seawater will decrease ambient pH considerably, negative consequences for deep-water ecosystems have been predicted. Hence, ecosystems associated with natural CO 2 reservoirs in the deep sea, and the dynamics of gaseous, liquid, and solid CO 2 in such environments, are of great interest to science and society. We report here a biogeochemical and microbiological characterization of a microbial community inhabiting deep-sea sediments overlying a natural CO 2 lake at the Yonaguni Knoll IV hydrothermal field, southern Okinawa Trough. We found high abundances ( 〉 10 9 cm −3 ) of microbial cells in sediment pavements above the CO 2 lake, decreasing to strikingly low cell numbers (10 7 cm −3 ) at the liquid CO 2 /CO 2 -hydrate interface. The key groups in these sediments were as follows: ( i ) the anaerobic methanotrophic archaea ANME-2c and the Eel-2 group of Deltaproteobacteria and ( ii ) sulfur-metabolizing chemolithotrophs within the Gamma- and Epsilonproteobacteria. The detection of functional genes related to one-carbon assimilation and the presence of highly 13 C-depleted archaeal and bacterial lipid biomarkers suggest that microorganisms assimilating CO 2 and/or CH 4 dominate the liquid CO 2 and CO 2 -hydrate-bearing sediments. Clearly, the Yonaguni Knoll is an exceptional natural laboratory for the study of consequences of CO 2 disposal as well as of natural CO 2 reservoirs as potential microbial habitats on early Earth and other celestial bodies.
Type of Medium:
Online Resource
ISSN:
0027-8424
,
1091-6490
DOI:
10.1073/pnas.0606083103
Language:
English
Publisher:
Proceedings of the National Academy of Sciences
Publication Date:
2006
detail.hit.zdb_id:
209104-5
detail.hit.zdb_id:
1461794-8
SSG:
11
SSG:
12
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