ENV100Y5 Lecture Notes - Lecture 15: Food Chain, Subduction, Nitrogen Cycle
69
ENV100Y5 Full Course Notes
Verified Note
69 documents
Document Summary
Session 15: evolution, biodiversity and population ecology (i) (14-10-15) Ocean is the second largest reservoir of carbon (largest in hydro cycle) Sources: atmosphere, terrestrial runoff, marine organisms, undersea volcanoes, hydrothermal vents. Short: (100s of yrs): rates of photosynthesis and respiration. Medium: (1,000s to millions of yrs): rates of deposition and burial of organic. Long: (millions to billions of yrs): rates of weathering, limestone formation, and matter plate tectonics. Mean global temp ~ 6. 2 c higher than today. No glacial ice; 85% of earth"s surface was water. Ironically, high temps triggered a brief ice age. Increased evaporation led to high snowfall at high latitudes/altitudes. Sea levels dropped dramatically, creating land bridges. Nh3 (ammonia); nitrous oxides: no2 (nitrite), no3 nitrate) N2 (molecular nitrogen) = 78% of atmosphere, but is biologically inert. Largest reservoir is atmosphere; some in sedimentary rocks. Deforestation, burning of biomass (biosphere atmosphere) Cattle and rice production (biosphere atmosphere)
