--> Abstract: The Biomineralisation Of Bacterial Biofilms, by F. Westall, C. C. Allen, D. S. Mckay, S. Kivett, P. Morris, and E. K. Gibson, Jr.; #90928 (1999).

Datapages, Inc.Print this page

WESTALL, FRANCES1, CARL C. ALLEN6, DAVID S. MCKAY5, STEVEN KIVETT2, PENNY MORRIS3, and EVERETT K. GIBSON, JR.4
1SN2-NASA-Johnson Space Center, Houston, TX
2University of Houston, Houston, TX
3University of Houston Downtown, Houston, TX
4SN2, Johnson Space Center, Houston TX
5SN-NASA Space Center, Houston, TX
6Lockheed Martin, Houston

Abstract: The Biomineralisation of Bacterial Biofilms

Bacterial biofilms are ubiquitous on surfaces in aqueous environments. Biofilms consist of colonies of different types of bacteria (among other microorganisms) embedded in a layer of microbially-produced mucopolysaccharides, as well as trapped detrital and precipitated minerals. We present examples of mineralised biofilms ranging in age from the early Archean to the present to demonstrate the hitherto unappreciated importance of this phenomenon in the rock record.

Bacteria mediate mineral formation by changing the physico-chemical conditions in their immediate environment and by providing attractive nucleation sites as organic templates for minerals. In addition, their extracellular polymeric secretions (EPS) can act as organic templates for mineral nucleation. It appears that mineralised biofilms in the geological fossil record may be more common in the rock record than the preservation of mineralised bacteria.

We are investigating the processes in which bacteria and EPS serve as organic templates and catalysts for mineral nucleation. Dissolved ions chelate to active groups on the surface of, and within, the organic template. Nucleation and growth of precipitated substances on or within bacteria or EPS may form amorphous masses or well crystallised minerals, or a combination of both.

We illustrate the mineralisation of bacteria and bacterial biofilms using both experimental studies and examples from the rock record: silicified bacteria and biofilms from the Early Archean Barberton greenstone belt in South Africa and the Pilbara block, Australia; phosphatised bacteria from the Early Eocene Messel Formation in S. Germany; silicified biofilms and bacteria from Early Miocene, South Atlantic, deep-sea sediments; silicified and calcified bacteria and biofilms from the hot springs, e.g. Yellowstone, Wyoming and New Mexico.

AAPG Search and Discovery Article #90928©1999 AAPG Annual Convention, San Antonio, Texas