Ancient microbial ecosystem

Article By:

Noffke, Nora Department of Ocean, Earth, and Atmospheric Sciences, Old Dominion University, Norfolk, Virginia.

Last reviewed:2014

DOI:https://doi.org/10.1036/1097-8542.YB150919

At first, it may appear paradoxical that we must study life in the context of modern Earth in order to understand the earliest life in the fossil record. The oldest part of Earth's history is preserved in rocks of the Archean time period, from about 4 to 2.5 billion (giga) years ago (GYA). Detailed research on the ancient marine sedimentary rocks exposed in the 3.48 billion-year-old Dresser Formation in the Pilbara area of Western Australia has revealed microfossils of individual cells of bacteria beautifully preserved in glasslike cherts (hard, dense sedimentary rock composed of fine-grained silica, most commonly quartz) and stromatolites (boulder-shaped architectural buildups created by microbiota from long ago). The Archean world of life, however, was vastly different in comparison to the world of life known today. Still, it is the investigation of microorganisms in comparable coastal environments of the present time that allows insight into the life and ecology of this ancient scenario. One avenue to follow is the study of microbially induced sedimentary structures (MISS).

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