In Wave Tanks, Microbial Fragments Wrangle Sands into Wrinkle Structures

Abstract

Wrinkle structures, found in ancient sedimentary environments along the surfaces of sandy beds, can be formed experimentally by adding microbial fragments to sand layers within wave tanks, according to Giulio Mariotti of the Massachusetts Institute of Technology (MIT) in Cambridge and his collaborators there and at Smith College in Northampton, Mass. They say that wrinkle structures in natural sediments are “morphological biosignatures” of microbial fragments—inscribed at the sediment–water interface in wave-dominated environments, and not beneath larger microbial mats as previously thought. Those wrinkle structures likely formed early during the evolution of animals, possibly while they were grazing on microbial fragments. Details appeared 31 August 2014 in Nature Geoscience Letters (doi:10.1038/ngeo2229).