Lyngbya aestuarii , an oscillatoriacean cyanophyte, forms surficial mats in portions of the salt marsh and evaporite flat at Laguna Mormona, a closed coastal lagoon on the Pacific coast of Baja California. Aggregations of this alga produce structures ranging from small-diameter mounds to tufts, rounded ridges, sharp-crested ridges, large-diameter flat-topped mounds, and rings. The specific structural type seems to be controlled largely by the overall filament abundance, flooding history, and water depth. Study of these Lyngbya aestuarii mats and associated tufted structures produced by other oscillatoriacean cyanophytes have a bearing on certain problems in Precambrian paleontology, including: the formation of the stromatolite Conophyton ; the origin of "molar-tooth" structure; and the effect of environmental factors on algal-mat structure.

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