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Responses Of Greenhouse Gas Emissions To Simulated Warming In Lakeside Wetlands Ofqinghai Lake

Posted on:2020-08-08Degree:MasterType:Thesis
Country:ChinaCandidate:Q WangFull Text:PDF
GTID:2370330578964400Subject:Physical geography
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The wetland carbon cycle is an important link carbon cycle of terrestrial ecosystems for responsingto the global change.With the increasing temperatures of the global surface and tropospheric atmospheric,the carbon exchange has significantly changed ofthe process of soil,vegetation and atmosphere in wetland ecosystems.The alpine lakeside wetland is a direct reaction zone for climate change.After the temperature rises,how does the greenhouse gas emission flux change of the alpine lakeside wetland ecosystem?during the plant growing season.What factors are controlled?These are not clear.This brings great uncertainty to predicte and assess of the carbon balance of the alpine wetland ecosystem under the background of global warming.In this study,xiaopo lake alpine marsh meadow wetland was taken as the study area.The warming was achieved using open-topchambers?OTCs?,it was used to simulate climate warming.The emission fluxes of CO2,CH4 and N2O were analyzed by using the static box-meteorological chromatography method,and the influencing factors were analyzed.The results showed that:?1?CO2 and CH4 in alpine lakeside wetlands are net emissions,with an average emission flux of 100.77 mg·m-2h-1 and 1.66 mg·m-2h-1,and the maximum emission flux appears in July,during the growing season.The N2O is weak emission,and the flux is 1.05?g·m-2h-1.The maximum emission fluxes of CO2 and CH4 appeared at 14o'clock.The peak value of N2O emission appeared at 24 o'clock,and the peak value of its absorption appeared at about 18 o'clock.?2?OTC treatment reduced the CO2 emission flux in the growing season of lakeside wetland by 9.03 mg·m-2h-11 on average compared with the control condition,and reduced the CH4 by 49.10%.Warming has the greatest influence on the emission flux of N2O,which transforms from a weak source to a weak sink.?3?There was a positive correlation between CO2 and CH4,CO2 and N2O,CH4and N2O emission fluxes,and R was 0.55,0.13 and 0.09,respectively?P<0.01?.Soil temperature of 10 cm and 20 cm has the positive impact on CO2 and CH4 emission fluxes,respectively.There was no correlation between N2O emission flux and soil and air temperature.?4?OTC treatment make the 10 cm and 20 cm soil temperature increased by1.85?and 1.53?,respectively;the aboveground biomass increased by 9.81%.Gramineae and Bryophytes increased,and weeds decreased.The soil organic matter in030 cm soil depth were increased.Soil porosity,pH value and bulk density decreased.The research results are not only valuable for studying climate change on greenhouse gas release from alpine wetlands,but also provide relevant reference materials for forecasting,estimating and evaluating greenhouse gas emissions in Qinghai Lake wetland.Providing a scientific reference for adaptive management policies for emissions and control of greenhouse gas emissions.
Keywords/Search Tags:warming, qinghai lake, lakeside wetland, greenhouse gases, influencing factors
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