Biogeochemical evolution

Most of the water on Earth s surfece is in the ocean relatively little is present in the atmosphere or on land. Because of its chemical and physical properties, this water has had a great influence on the continuing biogeochemical evolution of our planet. Most notably, water is an excellent solvent. As such, the oceans contain at least a little bit of almost every substance present on this planet. Reaction probability is enhanced if the reactants are in dissolved fitrm as compared with their gaseous or solid phases. Many of the chemical changes that occur in seawater and the sediments are mediated by marine organisms. In some cases, marine organisms have developed unique biosynthetic pathways to help them survive the environmental conditions fitimd only in the oceans. Some of their metabolic products have proven useful to humans as pharmaceuticals, nutraceuticals, food additives, and cosmeceuticals. 

This influence has continued for about 3.5-3.S billion years and the specific form of material entity, the living matter, has originated and accumulated during this period. For this reason, living matter plays the most important role in biogeochemical evolution of the outer layer of the Earth (see Chapter 2). 

The problems related to life s origin in the Earth are central and crucial in any discussion of biogeochemical evolution. Theoretical and experimental analyses of the origins of life occupied a considerable fraction of human thoughts and efforts. Until now it remains the central problem of many sciences, from theosophy to biology. 

Discuss the main peculiarities of carbon biogeochemical evolution. Present the isotopic record of this evolution in various fossil rocks. 

Quaternary 3 Myr Repeated glaciations. North and South America join mass extinctions of large mammals, evolution of Homo rise of civilizations, humans begin to modify biogeochemical cycles... 

The evolution of life on Earfh has depended on a sustained supply of nutrients provided by the physical environment. Life, in turn, has profoundly influenced the availability and cycling of these nutrients hence the inclusion of bio in biogeochemical cycles. The involvement of the biosphere with biogeochemical cycles has been determined by the evolution of life s biochemical properties in the context of the physical and chemical properties of planet Earth. 

Schetagne R, Verdon R. 1999. Post-impoundment evolution of fish mercury levels at the La Grande complex, Quebec, Canada (from 1978 to 1996). In Lucotte M, Schetagne R, Therien N, Langlois C, Tremblay A, editors. Mercury in the biogeochemical cycle. Berlin, Germany Springer, p. 235-258. 

Nutrient (biogeochemical) cycles Development and evolution Control... 

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