ENVR 200 Lecture Notes - Lecture 12: Primary Production, Lithosphere

• School: McGill University
• Department: Environment
• Course: ENVR 200
• Professor: George Mc Court

Document Summary

Patterns in atmospheric concentrations can be looked at on different time scales. Geologic processes and plate tectonics determine atmospheric co2 trends. C reservoirs are huge, but c turnover within them is very small (long residence time) Largest reservoirs are sedimentary rocks (limestone and organic carbon), oceanic bicar- bonate ion and fossil fuels. Weathering releases c and ocean sediment takes in c at equal rates. Net primary productivity = photosynthesis - plant respiration. Net ecosystem exchange = photosynthesis - all respiration. Co2 from the atmosphere is used for photosynthesis to create organic matter. Organic plant and animal c are rapidly buried. Buried plant matter may eventually form fossil fuels. Uplift, weathering and erosion release fossil fuel carbon back to the atmosphere. The burning of fossil fuels short circuits this cycle. Fossil fuels store the largest amount of organic carbon on earth. Significantly contributes to long-term trends in atmospheric co2. Makes up 75% of the earth/atmosphere co2 exchange.