Microfossils of sulphur-metabolizing cells in 3.4-billion-year-old rocks of Western Australia
Sulphur isotope data from early Archaean rocks suggest that microbes with metabolisms based on sulphur existed almost 3.5 billion years ago, leading to suggestions that the earliest microbial ecosystems were sulphur-based1, 2, 3, 4, 5. However, morphological evidence for these sulphur-metabolizing bacteria has been elusive. Here we report the presence of microstructures from the 3.4-billion-year-old Strelley Pool Formation in Western Australia that are associated with micrometre-sized pyrite crystals. The microstructures we identify exhibit indicators of biological affinity, including hollow cell lumens, carbonaceous cell walls enriched in nitrogen, taphonomic degradation, organization into chains and clusters, and δ13C values of −33 to −46‰ Vienna PeeDee Belemnite (VPDB). We therefore identify them as microfossils of spheroidal and ellipsoidal cells and tubular sheaths demonstrating the organization of multiple cells. The associated pyrite crystals have Δ33S values between −1.65 and +1.43‰ and δ34S values ranging from −12 to +6‰ Vienna Canyon Diablo Troilite (VCDT)5. We interpret the pyrite crystals as the metabolic by-products of these cells, which would have employed sulphate-reduction and sulphur-disproportionation pathways. These microfossils are about 200 million years older than previously described6 microfossils from Palaeoarchaean siliciclastic environments.
作 者：David Wacey; Matt R. Kilburn; Martin Saunders; John Cliff; Martin D. Brasier
期刊名称： Nature Geoscience
期卷页： 2011-08-21 第卷 第期 ~页
学科领域：地球科学 » 地质学 » 古生物学和古生态学
添加人是否为作者: 否
原文链接：http://www.nature.com/ngeo/journ ... /full/ngeo1238.html
DOI： doi:10.1038/ngeo1238
ISBN： 1752-0894作者: 图兰朵 时间: 24-10-2011 10:18
鸟版，快一个月了，你到哪里去了？作者: 启程搬运 时间: 24-10-2011 12:47
澳洲人也研究这个