火山口湖温室气体释放规模研究

Output of greenhouse gas from volcanic lakes

火山口湖是地球上最为壮观的自然地貌之一。作为连接地表系统和地球深部岩浆-水热系统的纽带,火山口湖是探索火山系统内部地质作用的重要窗口,也是地球深部碳循环的重要环节。本研究在全球火山湖温室气体排放研究的基础上,对火山口湖、玛珥湖和火山-构造有关的湖泊CO_(2)排放数据进行了甄别与梳理,对火山口湖和玛珥湖温室气体释放特征进行了初步探讨;同时,以我国长白山天池火山口湖为例,初步估算了天池火山口湖温室气体的释放规模,并就火山口湖温室气体释放研究进行了展望。初步研究结果表明,火山口湖的CO_(2)释放规模和释放速率整体上高于玛珥湖和火山-构造湖。火山口湖CO_(2)释放规模明显受火山活动的影响,对火山活动具有较高的灵敏度,是不可忽视的CO_(2)重要来源。作为我国典型的火山口湖,长白山天池通过水-气界面扩散向大气中输送的CO_(2)规模为3.44×10^(4)t/a,大量CO_(2)溶解于湖水中,湖水中溶解的CO_(2)规模为1.96×10^(5)t。结合以往研究,初步估算整个长白山天池火山区通过湿脱气系统向大气中释放的CO_(2)约占整个火山区CO_(2)释放总量的28%。虽然本研究仅对我国长白山天池火山口湖温室气体排放规模进行了初步估算,但是随着研究程度的不断深入、调查范围的不断扩大,火山口湖温室气体排放规模将会越来越精细,火山区温室气体碳排放研究也会越来越系统,火山区碳循环的路径也将会越来越清晰。

Crater lakes are one of the most spectacular natural landforms on the Earth,linking the Earth surface system and deep magma-hydrothermal system,and being also an important part of the global deep carbon cycle.In this study,we systematically collected 127 reported data of CO_(2) emissions from 76 volcanic lakes,including the volcanic lakes,maar lakes,and volcanic-tectonic lakes,and the characteristics of CO_(2) emission from crater lakes were analyzed.Also,the amounts of CO_(2) by water-air diffuse emission and CO_(2) dissolved in the Tianchi crater lake(42.01°N,128.05°E)in Mt.Changbai volcanic field were quantitatively estimated.The results indicate that the amount of CO_(2) emissions from crater lakes are higher than that from the maar lakes and volcanic-tectonic lakes.The CO_(2) emission of the volcanic lake is significantly affected by volcanic activity,which is much more sensitivity to volcanic activity.In the Tianchi crater lake,which is the largest crater lake in China,the amount of CO_(2) diffuse emission through the water-air surface is estimated to be 3.44×10^(4)t/a.The amount of CO_(2) dissolved into the lake water is estimated to be 1.96×10^(5)t,indicating large amounts of CO_(2) dissolved in the lake water.Comparing to the CO_(2) emissions from soil in the Mt.Changbai volcanic field,the result of this study indicates that the amount of CO_(2) from crater lake and maar lake plays an important role in the carbon budget in the Mt.Changbai volcanic field.Although this study is a preliminary estimate of the scale of greenhouse gas emissions from volcanic lake in China,with the deepening of the research and the expansion of the scope of investigation,the amount of greenhouse gas emissions from volcanic lakes will become more and more precise.