Largest known microbialites discovered in Lake Van, Turkey

摘要: MICROBIALITES are organosedimentary deposits produced by benthic microbial communities interacting with detrital or chemical sediments1. Calcareous cyanobacterial microbialites defined as stromatolites and thrombolites were common in ancient shallow marine environments2. Today, they restricted to a few lacustrine perimarine settings. This restriction may result from changes seawater chemistry through time3–6, particularly alteration supersaturation respect carbonate minerals7. The largest known calcareous (several metres high) formed the late Precambrian8. Here we report discovery of enormous (∼40 m tower-like alkaline (pH>9.7) Lake Van, eastern Anatolia. Growth is mats coccoid cyanobacteria (Pleurocapsa group) permineralizing situ aragonite inorganically precipitated calcite. Certain aspects these resemble Proterozoic stromatolites9.