GEOG 3P85 Lecture Notes - Lecture 6: Radiative Forcing, Sodium Chloride, Ecosystem Services
16 Jul 2015
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Document Summary
Nitrogen: unreactive n is n2 (79% of earth"s atmosphere, reactive n (nr is all biol, chem & physically active n compounds in atmos. Agricultural, freshwater, coastal ecosystems: most n leaves agroecosystem as pollution, nr acidifies water = biodiversity loss, algal blooms, increased o2 demand (hypoxia, nox are greenhouse gases, nitrous oxides nox = smog, n2o speeds stratospheric o3 depletion. Other biogeochemical cycles: mining mobilizes toxic metals (e. g. , mercury, lead, cadmium, vehicle exhaust, car tires, road salt, pm10. Impacts vary: direct/indirect/insidious: some kill zones are obvious (sudbury?, organisms sense the change even if we don"t communities change, biomonitoring can be used to detect spatial trends. 10-30% of radiative forcing since 1750 largely due to methane and nitrous oxide). In 19th and early 20th century ecosystems were a net source of co2: methane (ch4 )preindustrial was 700 ppb, now is 1750 ppb.
