ENVS 202 1st Edition Lecture 7 Outline of Last Lecture I. Intro to Agriculture and Aquaculture II. Agriculture III. Soils IV. AquacultureOutline of Current Lecture I. Intro to WetlandsII. Wetlands and CarbonIII. Wetlands and ClimateCurrent LectureI. Intro to WetlandsWetland functions: removal/filtration of pollution, maintenance of high water table, long term surface water storage Global wetland area: primarily bogs and ferns around the equator; primarily bogs, swamps, floodplains more towards the polesWetland and aquatic areas and loss rates are highly uncertainWetlands = 8.9 x 10^6 km^2 (6% of land loss) (40% loss)Aquatic = 5.0 x 10^6 km^2 (3.3% of land mass)II. Wetlands and CarbonWetlands have very high soil carbon densitiesTerrestrial ecosystems range from 1-238 (Mg C ha^-1)These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.Boreal peat has a very high carbon concentration, accumulates over 10s of thousands of yearsWetland conversion oxidizes 1,183 Tg C yr^-1, with 460 Tg C yr^-1 coming from peatlandsWetlands have very high soil C accumulation rates (terrestrial ~1-5)Wetlands accumulate 38% and aquatic ecosystems 39% of global soil C sequestrationIII. Wetlands and ClimateWithin large error bounds, wetlands contain enormous amounts of CSome have exceptionally high rates of soil C sequestration, removing CO2 from the atmosphereDestruction of wetlands, specifically peatlands, gives off large amounts of CO2 from the atmosphereIPCC AR5 Global Warming Potentials for Methane (CH4)Without climate-carbon feedbacks: 20 years- 84 100 years- 28With climate-carbon feedbacks: 20 years- 86 100 years- 34All wetlands will eventually have a net cooling effect, but this could take hundreds to thousands of yearsWetlands produce about 1/3 of global methane emissionsTropical mineral-soil wetlands are a massive source of global CH4 emissionWarming effects: soil C oxidation, loss of soil C sequestration Cooling effects: decrease in CH4,
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