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Alexandru I. Petrisor, Alan W. Decho. Analysis of the Orientation of Cyanobacteria in Bahamian Stromatolite Mats Using a Digital Image Analysis and GIS-Based Approach. Studia Universitatis Babes-Bolyai - Biologia, 51(1), pp. 71-81, 2006.

Abstract: Oldest known macrofossils on Earth, marine stromatolites are known to result from microbially mediated processes, and are still forming in remote environments. The microbial mats of stromatolites are fueled by cyanobacterial autotrophy. Several studies documented that cyanobacteria are able to move within these environments. Previous observations of stromatolites documented a preferential orientation of cyanobacteria, but there was no mathematical model available to test it. This study quantitatively analyzed images obtained with a scanning confocal laser microscope using a combination of image analysis and Geographical Information Systems techniques in conjunction with a mathematical model to test whether there is a preferential orientation of cyanobacteria. Analyses indicate that the vertical orientation is significantly predominant in Type 1 mats (p=0.0010) and below the top of mats (p=0.0342). Even though there are limitations of this method due to the effects of microscale topology, mounting of samples for microscopic analyses, image classification aspects, and mathematical modeling, the approach used to address the research questions presented in this paper is the only quantitative one. Future studies should focus on examining the influence of several known factors, such as light conditions, on the orientation of cyanobacteria.

Keywords: stromatolites, cyanobacteria, phototaxis, GIS, digital image analysis


Posted by Alexandru-Ionut Petrisor


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