ENV100Y5 Lecture Notes - Lecture 16: Nitrogen Fixation, Phosphorus Cycle, Seafloor Spreading

• School: UTM
• Department: Environment
• Course: ENV100Y5
• Professor: Barbara Murck

Document Summary

Chapter 3 - ecosystem ecology (part 3) Tuesday, october 13, 2015. Sedimentary rock = largest carbon reservoir. Residence time: millions of years. Ocean is the second largest reservoir of carbon. Sources: atmosphere, terrestrial runoff, marine organisms, undersea volcanoes, hydrothermal vents. Carbon cycle functions on multiple timescales. Short:(100s of yrs): rates of photosynthesis and respiration. Medium: (1,000s to millions of yrs): rates of deposition and burial of organic matter. Long: (millions to billions of yrs): rates of weathering, limestone formation, and plate tectonics. [co2] were 4x higher than today. Mean global temp ~ 6. 2 c higher than today. Caused by rapid sea floor spreading. No glacial ice; 85% of earth"s surface was water. Things were alive, but it was a diff world (greenhouse earth) 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. When you lower sea levels you make land bridges.