Biophysical basis for the geometry of conical stromatolites
Name
9956.full.pdf
Size
2.17 MB
Format
Adobe PDF
Checksum (MD5)
8631cc00c4b1825733934b4e4af9018b
Author(s)
Maslov, A.
Krupenin, M.
Petroff, Alexander Peter
Sim, Min Sub
Bosak, Tanja
Rothman, Daniel H.
Date Issued
May 2010
Journal
Proceedings of the National Academy of Sciences
Publisher
National Academy of Sciences (U.S.)
Citation
Petroff, A. P. et al. “Biophysical Basis for the Geometry of Conical Stromatolites.” Proceedings of the National Academy of Sciences 107, 22 (May 2010): 9956–9961 © 2010 The Authors
Version
Final published version
Abstract
Stromatolites may be Earth's oldest macroscopic fossils; however, it remains controversial what, if any, biological processes are recorded in their morphology. Although the biological interpretation of many stromatolite morphologies is confounded by the influence of sedimentation, conical stromatolites form in the absence of sedimentation and are, therefore, considered to be the most robust records of biophysical processes. A qualitative similarity between conical stromatolites and some modern microbial mats suggests a photosynthetic origin for ancient stromatolites. To better understand and interpret ancient fossils, we seek a quantitative relationship between the geometry of conical stromatolites and the biophysical processes that control their growth. We note that all modern conical stromatolites and many that formed in the last 2.8 billion years display a characteristic centimeter-scale spacing between neighboring structures. To understand this prominent - but hitherto uninterpreted -organization, we consider the role of diffusion in mediating competition between stromatolites. Having confirmed this model through laboratory experiments and field observation, we find that organization of a field of stromatolites is set by a diffusive time scale over which individual structures compete for nutrients, thus linking form to physiology. The centimeter-scale spacing between modern and ancient stromatolites corresponds to a rhythmically fluctuating metabolism with a period of approximately 20 hr. The correspondence between the observed spacing and the day length provides quantitative support for the photosynthetic origin of conical stromatolites throughout geologic time. Keywords: geobiology; photosynthesis; cyanobacteria; microbialite
MIT Department
Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences
Terms of Use
Creative Commons Attribution 4.0 International License
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1073/pnas.1001973107
