The Proterozoic Biosphere: Modern Mat-Building Microbial Communities: a Key to the Interpretation of Proterozoic Stromatolitic Communities

摘要: Introduction Modern microbial mats are structurally coherent macroscopic accumulations of microorganisms. Mats widely distributed on earth. They found in a surprisingly large number diverse environments from the equatorial zones to both polar regions. vary size extensive terrestrial and hypersaline that cover areas several square kilometers extent minute only few centimeters area small thermal springs. thickness massive measured meters, such as those Persian Gulf Red Sea region, thin films less than millimeters thickness. In addition being highly varied size, modern also very morphology, community structure, physiological characteristics. What do have common? Under what conditions they form? is basis their diversity? insight provide, if any, interpretation widespread stromatolites Proterozoic? A Terminology Microbial accretionary cohesive communities which often laminated growing at sediment-water (occasionally sediment-air) interface. Most stabilize unconsolidated sediment. The comprised various microorganisms accumulate along with metabolic products. most conspicuous these products usually copious amount extracellular polysaccharide helps hold cells together form structure.