Stromatolites (biostromes) grow in profusion in the Great Salt Lake. Algae (really cyanobacteria) grow on the lake bottom and due to their photosynthesis the pH changes, and this causes limestone (calcium carbonate) to precipitate. Over decades and millennia, solid rock stromatolites are formed. In the Great Salt Lake they are the primary solid substrate in the lake, and thus serve as substrate for brine fly larvae and pupae.


Photo: Fremont Island, June 2008