ENV100Y5 Lecture Notes - Lecture 14: Phosphorus Cycle, Nitrogen Fixation, Nitrogen Cycle
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ENV100Y5 Full Course Notes
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Humans affect the carbon cycle: carbon mobilization, burning fossil fuels (geosphere -> atmosphere, move from one reservoir to another, deforestation, burning of biomass (biosphere -> atmosphere, cattle and rice production (biosphere -> atmosphere) Livestock produces 18% of greenhouse gases: 1. 5 billion cattle worldwide. Impact of intensive livestock farming on the environment is massive: atmospheric co2 reservoir, missing carbon sink: 1-2 billion metric tons of carbon are unaccounted for, plants or soils of northern temperate and boreal forests. Increased transfer from rivers to oceans; changes to estuaries, coastal ecosystems, and fisheries - eutrophication, algal blooms, hypoxia: eutrophication, nutrient over-enrichment -> algal blooms -> hypoxia (oxygen deficiency) Fossil fuel burning, deforestation, and agriculture contribute significantly to changes in biogeochemical cycles. Evolution, biodiversity and population ecology: populations change (evolve) over time, over time, populations may diverge and form new species. Darwin"s dangerous ideas: evolutionary change by descent with modification, natural selection produces adaptations. Evolution: change in the genetic composition of a population.