湖泊甲烷释放特征及其影响因素研究进展

Research progress on methane emission characteristics and influencing factors in lakes

湖泊被认为是重要的且被低估了的温室气体释放源,而甲烷(CH_(4))是湖泊释放温室气体的重要组成。研究表明,湖泊生态系统中CH_(4)的产生和氧化过程主要受水体和沉积物中产甲烷菌和甲烷氧化菌的活动所控制。水温、pH、溶解氧浓度、营养盐等因素都可能影响湖泊CH_(4)释放通量。本文利用Web of Science与CNKI作为检索平台,调研了全球不同地区80个湖泊水-气界面CH_(4)释放通量。结果表明,CH_(4)平均释放通量为2.56 mmol·m^(-2)·d^(-1)(范围为0.001~40.3 mmol·m^(-2)·d^(-1))。其中南美洲地区和欧洲地区湖泊CH_(4)释放通量显著高于非洲地区湖泊,富营养湖泊向大气释放的CH_(4)显著高于中营养湖泊和贫营养湖泊,面积<1 km^(2)的湖泊向大气释放的CH_(4)显著高于面积10~<100 km^(2)和面积≥100 km^(2)的湖泊,低海拔地区湖泊向大气释放的CH_(4)显著高于高海拔地区湖泊和超高海拔地区湖泊,夏季湖泊向大气释放的CH_(4)显著高于春季湖泊、秋季湖泊和冬季湖泊。在温暖季节低海拔地区的富营养化和小型浅水湖泊是CH_(4)释放的热点区域,未来需进一步结合微生物产生和氧化CH_(4)机制分析加强CH_(4)释放通量的日变化研究,为估算全球气候变暖背景下湖泊CH_(4)释放量提供科学依据。

Greenhouse gases released by lakes are considered important and are underestimated sources of greenhouse gas emissions.Methane is an important component of greenhouse gas emissions from lakes.Previous studies have shown that the CH_(4)production and oxidation processes in lake ecosystems are mainly controlled by the activities of methanogens and methane-oxidizing bacteria in water bodies and sediments.Factors such as water temperature,pH,dissolved oxygen concentration,and nutritional status may affect the CH_(4)emission flux in lakes.This study used the Web of Science and CNKI as search platforms to investigate the CH_(4)emission flux at the water air interface of 80 lakes in different regions of the world.The results showed that the CH_(4)emission flux was 2.56 mmol·m^(-2)·d^(-1)(ranging from 0.001 to 40.3 mmol·m^(-2)·d^(-1)).The CH_(4)emission flux from lakes in South America and Europe was significantly higher than that of lakes in Africa,and the CH_(4)emissions from eutrophic lakes to the atmosphere was significantly higher than that from medium and poornutrient lakes.Lakes with an area of less than 1 km^(2)emitted significantly more CH_(4)into the atmosphere than lakes with an area of 10 km^(2)to 100 km^(2)and lakes with an area of more than 100 km^(2).The release of CH_(4)into the atmosphere from lakes in low altitude areas was significantly higher than that from lakes in high altitude areas and lakes at ultra-high altitudes.Methane emissions into the atmosphere by lakes in summer was significantly higher than that in spring,autumn,and winter.During the warm season,eutrophication in low altitude areas and small shallow lakes were hot spots for CH_(4)emissions.In the future,further integration of microbial production and CH_(4)oxidation mechanisms and strengthening of research on daily variation is needed to estimate CH_(4)emission flux to provide a scientific basis for studying the amount of CH_(4)emissions from lakes considering global climate change.