CMMB 343 Lecture Notes - Lecture 5: Macrophyte, Soil Horizon, Stromatolite
22 Jan 2019
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Generally only occur today in extreme environments that eukaryotes are not adapted to (shark bay, pavilion lake, etc. ), probably because they cannot be grazed on by animals and do not need to compete with macrophyte algae for light. Predominant in the ancient fossil record before the rise of multicellular organisms (1200 ma. When microbial mats grow in big agglomerates, they are called microbialite. Mircobialite is made from a variety of things. Cyanobacteria grow in stromatolite structures where there are no fish around. Fossil stromatolites have been found up to 3. 5 ga-old with typical laminar structure caused by alternating layers of cells and cemented debris (carbonate) Shark bay: cut off from the ocean, as the water evaporates, it becomes hyper saline and you get massive growths of cyanobacteria because fish can"t survive in that environment. Layers: main lines of evidence that cyanobacterial life came at least 3. 5 billion years ago. Inorganic mineral matter (~ 40% of soil volume)
