Editing Stromatolite (section)

===Formation===
Time lapse photography of modern microbial mat formation in a laboratory setting gives some revealing clues to the behavior of cyanobacteria in stromatolites. Biddanda ''et al.'' (2015) found that cyanobacteria exposed to localized beams of light moved towards the light, or expressed [[phototaxis]], and increased their [[Photosynthesis|photosynthetic]] yield, which is necessary for survival.<ref name="Biddanda-2015">{{Cite journal|last1=Biddanda|first1=Bopaiah A.|last2=McMillan|first2=Adam C.|last3=Long|first3=Stephen A.|last4=Snider|first4=Michael J.|last5=Weinke|first5=Anthony D.|date=2015-01-01|title=Seeking sunlight: rapid phototactic motility of filamentous mat-forming cyanobacteria optimize photosynthesis and enhance carbon burial in Lake Huron's submerged sinkholes|journal= Frontiers in Microbiology|pages=930|doi=10.3389/fmicb.2015.00930|pmc=4561352|pmid=26441867|volume=6|doi-access=free}}</ref> In a novel experiment, the scientists projected a school logo onto a petri dish containing the organisms, which accreted beneath the lighted region, forming the logo in bacteria.<ref name="Biddanda-2015" /> The authors speculate that such motility allows the cyanobacteria to seek light sources to support the colony.<ref name="Biddanda-2015" /> 

In both light and dark conditions, the cyanobacteria form clumps that then expand outwards, with individual members remaining connected to the colony via long tendrils. In harsh environments where mechanical forces may tear apart the microbial mats, these substructures may provide evolutionary benefit to the colony, affording it at least some measure of shelter and protection. 

[[Lichen stromatolite]]s are a proposed mechanism of formation of some kinds of layered rock structure that are formed above water, where rock meets air, by repeated colonization of the rock by [[endolithic lichen]]s.<ref name="CKLS">Lichen Stromatolites: Criterion for Subaerial Exposure and a Mechanism for the Formation of Laminar Calcretes (Caliche), Colin F. Klappa, [[Journal of Sedimentary Petrology]], Vol. 49 (1979) No. 2. (June), Pages 387–400, [http://archives.datapages.com/data/sepm/journals/v47-50/data/049/049002/0387.htm?doi=10.1306%2F212F7752-2B24-11D7-8648000102C1865D] {{Webarchive|url=https://web.archive.org/web/20141028133556/http://archives.datapages.com/data/sepm/journals/v47-50/data/049/049002/0387.htm?doi=10.1306%2F212F7752-2B24-11D7-8648000102C1865D|date=28 October 2014}}</ref><ref name="TTKP">Paleobotany: The Biology and Evolution of Fossil Plants, Edith L. Taylor, Thomas N. Taylor, Michael Krings, page [http://archives.datapages.com/data/sepm/journals/v47-50/data/049/049002/0387.htm?doi=10.1306%2F212F7752-2B24-11D7-8648000102C1865D] {{Webarchive|url=https://web.archive.org/web/20141028133556/http://archives.datapages.com/data/sepm/journals/v47-50/data/049/049002/0387.htm?doi=10.1306%2F212F7752-2B24-11D7-8648000102C1865D|date=28 October 2014}}</ref>