长白山亚高山针叶林沼泽湿地碳源/汇沿水分环境梯度变化规律  

Variation of carbon source/sink of subalpine coniferous forested wetland along water environmental gradient in Changbai Mountains of China

作　　者：李美霖 牟长城[1] 孙梓淇 王婷[1] 王文婧 LI Meilin;MU Changcheng;SUN Ziqi;WANG Ting;WANG Wenjing(Center for Ecological Research,Northeast Forestry University,Harbin 150040,China)

机构地区：[1]东北林业大学生态研究中心,哈尔滨150040

出　　处：《生态学报》2024年第6期2256-2269,共14页Acta Ecologica Sinica

基　　金：国家重点研发计划项目(2016YFA0600803)。

摘　　要：高纬度和高海拔区为气候变化敏感区,该区域湿地碳循环与气候反馈关系倍受关注。为探究在全球变暖背景下高海拔区沼泽湿地碳源/汇功能是否发生了转化,以长白山高海拔区沿水分环境梯度分布的5种沼泽类型(草丛沼泽-C、灌丛沼泽-G、落叶松泥炭藓沼泽-LN、落叶松藓类沼泽-LX、落叶松苔草沼泽-LT)为对象,采用静态箱-气相色谱法和相对生长方程法,同步测定各沼泽类型全年尺度上的土壤异养呼吸碳排放量(CO_(2)和CH_(4))、植被年净固碳量及相关环境因子(温度、水位和土壤有机碳等),并依据生态系统净碳收支平衡,量化各沼泽类型的碳源/汇作用,揭示其沿水分环境梯度变化规律及形成机制。结果表明:(1)5种沼泽类型土壤CO_(2)年均通量((97.68±8.64)—(291.01±18.31)mg m^(-2)h^(-1))沿水分环境梯度呈阶梯式递增规律性(环境梯度上部生境地段的落叶松苔草沼泽和落叶松藓类沼泽最高,中部生境地段的落叶松泥炭藓沼泽和灌丛沼泽居中,草丛沼泽最低);(2)CH_(4)年均通量((-0.051±0.003)—(0.087±0.001)mg m^(-2)h^(-1))在水分环境梯度经常积水生境地段的草丛沼泽和灌丛沼泽表现出CH_(4)排放源,而在偶有积水生境地段的3种针叶林沼泽却表现为CH_(4)吸收汇;(3)这些沼泽类型土壤CO_(2)排放量均受5或10 cm土壤温度所促进(C和G还分别受土壤有机碳或水位所抑制);草丛沼泽和灌丛沼泽CH_(4)排放量分别受10 cm土壤温度促进或10 cm土壤温度和水位共同促进,而3种森林沼泽CH_(4)吸收量仅受0或5 cm土壤温度所促进;(4)植被年净固碳量((1.22±0.29)—(3.14±0.36)t C hm^(-2)a^(-1))沿水分环境梯度也呈阶梯式递增规律性;(5)5种沼泽类型均表现为碳的排放源((-3.84±0.20)—(-1.12±0.45)t C hm^(-2)a^(-1)),且均表现为气候变暖效应(GWP:(4.31±1.65)—(13.96±0.72)t CO_(2)hm^(-2)a^(-1)),二者沿水分环境梯度呈阶梯式递增规律性(环境梯度上部生The high latitude and altitude areas are sensitive to climate change,and the feedback relationship between the wetland carbon cycle and climate in these areas has attracted much attention.This article aimed to explore whether the carbon source/sink function of swamp wetlands has been transformed under the background of global warming in the high altitude area.The carbon emissions(CO_(2) and CH_(4))of soil heterotrophic respiration,annual net carbon sequestration of vegetation,and related environmental factors(e.g.,temperature,water level,and soil organic carbon)were measured over one year by the static chamber gas chromatography and the relative growth equation method in five kinds of natural swamps(Carex schmidtii marsh-C,Shrub Swamp-G,Larix olgensis-Sphagnum magellanicum swamp-LN,Larix olgensis-moss swamp-LX,and Larix olgensis-Carex schmidtii swamp-LT)distributed along the water environment gradient in the high altitude area of Changbai Mountain.According to the net carbon balance of the ecosystem,the carbon source/sink effect of each swamp type was quantified,and the change law and formation mechanism were revealed along the water environment gradient.The results showed that:(1)the annual average emission fluxes of CO_(2) from five swamps((97.68±8.64)—(291.01±18.31)mg m^(-2) h^(-1))increased by the stepped type along the water environment gradient(LT and LX were the highest in the upper habitat section of the environmental gradient,LN and G were in the middle while C was the lowest);(2)The annual average fluxes of CH_(4)((-0.051±0.003)—(0.087±0.001)mg m^(-2) h^(-1))from C and G showed CH_(4) emission sources at the lower moisture gradient;while three coniferous swamps showed CH_(4) absorption sink at the upper habitat;(3)The fluxes of CO_(2) emission from the five kinds of swamps were promoted by 5 or 10 cm soil temperature(C and G was inhibited by soil organic carbon or water level);the fluxes of CH_(4) emission from C and G were mainly promoted by 10 cm soil temperature or 10 cm soil temperature and

关 键 词：高海拔 沼泽湿地 温室气体排放 年净固碳量 碳源/汇 全球增温潜势 

分 类 号：X171.1[环境科学与工程—环境科学]