朱先進(jìn),于貴瑞,王秋鳳,高艷妮,趙新全,韓士杰,閆俊華

(1. 中國(guó)科學(xué)院地理科學(xué)與資源研究所生態(tài)網(wǎng)絡(luò)觀測(cè)與模擬重點(diǎn)實(shí)驗(yàn)室CERN綜合研究中心, 北京 100101; 2. 中國(guó)科學(xué)院大學(xué), 北京 100049; 3. 中國(guó)科學(xué)院西北高原生物研究所, 西寧 810001; 4. 中國(guó)科學(xué)院沈陽(yáng)應(yīng)用生態(tài)研究所, 沈陽(yáng) 110016; 5. 中國(guó)科學(xué)院華南植物園, 廣州 510650)

典型森林和草地生態(tài)系統(tǒng)呼吸各組分間的相互關(guān)系

朱先進(jìn)1,2,于貴瑞1,*,王秋鳳1,高艷妮1,2,趙新全3,韓士杰4,閆俊華5

(1. 中國(guó)科學(xué)院地理科學(xué)與資源研究所生態(tài)網(wǎng)絡(luò)觀測(cè)與模擬重點(diǎn)實(shí)驗(yàn)室CERN綜合研究中心, 北京 100101; 2. 中國(guó)科學(xué)院大學(xué), 北京 100049; 3. 中國(guó)科學(xué)院西北高原生物研究所, 西寧 810001; 4. 中國(guó)科學(xué)院沈陽(yáng)應(yīng)用生態(tài)研究所, 沈陽(yáng) 110016; 5. 中國(guó)科學(xué)院華南植物園, 廣州 510650)

生態(tài)系統(tǒng)呼吸是陸地生態(tài)系統(tǒng)碳收支的重要組成部分,分析其組分間的相互關(guān)系對(duì)理解生態(tài)系統(tǒng)呼吸過(guò)程和精確評(píng)價(jià)生態(tài)系統(tǒng)碳收支具有重要意義,也是當(dāng)前碳循環(huán)研究工作的一大難點(diǎn)。利用ChinaFLUX的長(zhǎng)白山溫帶針闊混交林(CBS),鼎湖山亞熱帶常綠闊葉林(DHS)和海北灌叢草甸(HBGC)3個(gè)典型生態(tài)系統(tǒng)的通量觀測(cè)數(shù)據(jù),分析了經(jīng)驗(yàn)統(tǒng)計(jì)方法在中國(guó)典型生態(tài)系統(tǒng)中的適用性及敏感性,揭示了生態(tài)系統(tǒng)呼吸各組分的動(dòng)態(tài)變化特征及相互關(guān)系。結(jié)果表明：采用呼吸組分拆分方法所獲結(jié)果與理論推測(cè)及實(shí)測(cè)數(shù)據(jù)大致相同,拆分結(jié)果對(duì)凈初級(jí)生產(chǎn)力與總初級(jí)生產(chǎn)力比值(NPP/GPP)的變化較為敏感,NPP/GPP變化0.1時(shí),自養(yǎng)呼吸在生態(tài)系統(tǒng)呼吸中的比例(Ra/RE)改變0.05。各生態(tài)系統(tǒng)中,生態(tài)系統(tǒng)呼吸及其組分在年內(nèi)均表現(xiàn)出明顯的單峰型變化特征,在夏季生長(zhǎng)旺盛的時(shí)節(jié)達(dá)到最大值。異養(yǎng)呼吸與生態(tài)系統(tǒng)呼吸的比值(Rh/RE)也具有明顯的季節(jié)變化,但在生態(tài)系統(tǒng)間表現(xiàn)出明顯差異,CBS和HBGC分別表現(xiàn)出先增大后減小和先減小后增大的變化趨勢(shì),DHS則相對(duì)穩(wěn)定,在0.5附近波動(dòng), Ra/RE的季節(jié)動(dòng)態(tài)與Rh/RE相反。在年總量上,HBGC主要通過(guò)異養(yǎng)呼吸向大氣排放CO2,異養(yǎng)呼吸占生態(tài)系統(tǒng)呼吸的60%,而CBS和DHS的自養(yǎng)呼吸和異養(yǎng)呼吸所占比重大致相似,異養(yǎng)呼吸占生態(tài)系統(tǒng)呼吸的49%。這說(shuō)明,經(jīng)驗(yàn)統(tǒng)計(jì)學(xué)模型可以用來(lái)進(jìn)行生態(tài)系統(tǒng)呼吸組分的拆分,進(jìn)而可以為生態(tài)系統(tǒng)碳循環(huán)過(guò)程的精細(xì)研究提供參考數(shù)據(jù),但今后應(yīng)加強(qiáng)NPP/GPP的測(cè)定,以提高生態(tài)系統(tǒng)呼吸拆分的精度。

陸地生態(tài)系統(tǒng)；生態(tài)系統(tǒng)呼吸；渦度相關(guān)；碳通量；自養(yǎng)呼吸；異養(yǎng)呼吸

生態(tài)系統(tǒng)呼吸(RE)是碳循環(huán)的重要分量[1],與氣候變化間存在著正反饋效應(yīng)[2- 3],不僅在當(dāng)前全球碳收支中占有較大的比重,而且在未來(lái)還會(huì)呈現(xiàn)不斷增大的趨勢(shì)[4]。已有研究表明,全球的RE約為103 PgC a-1[5],占全球總初級(jí)生產(chǎn)力(GPP)總量(123 PgC a-1[6])的83.74%。

按照呼吸底物的不同,RE可分為自養(yǎng)呼吸(Ra)和異養(yǎng)呼吸(Rh)。其中,Ra是植物維持自身生命活動(dòng)所必需的新陳代謝過(guò)程,又分為維持呼吸和生長(zhǎng)呼吸。維持呼吸與溫度相關(guān),隨著溫度的增加呈指數(shù)增加[7]；生長(zhǎng)呼吸與溫度沒(méi)有直接關(guān)系,但與GPP呈一定的比例[8]。Rh是殘存有機(jī)質(zhì)分解并向大氣釋放CO2的過(guò)程[9],主要受土壤溫濕度和有機(jī)質(zhì)含量的影響[10]。因而,影響RE組分的因素存在差異,拆分RE的各個(gè)組分、分析各組分間的相互關(guān)系有助于深入認(rèn)識(shí)生態(tài)系統(tǒng)碳循環(huán)的過(guò)程機(jī)理,也可為陸地生態(tài)系統(tǒng)碳收支的精確評(píng)估提供理論依據(jù)。同時(shí),Ra的變化對(duì)大氣CO2濃度具有重要影響[11],科學(xué)界迫切需要拆分和評(píng)估RE的各組分,為評(píng)價(jià)Ra對(duì)大氣CO2濃度變化的貢獻(xiàn)提供數(shù)據(jù)。

目前,拆分RE組分的方法有許多種。第1種是將箱式法與渦度相關(guān)系統(tǒng)觀測(cè)相結(jié)合,分別獲取土壤呼吸(Rs)和RE,實(shí)現(xiàn)RE組分的拆分[12- 14]。然而,基于箱式法獲取的Rs包含了Ra和Rh,對(duì)Rs進(jìn)行拆分也是一項(xiàng)艱巨的工作。第2種是利用生物量調(diào)查法獲取生態(tài)系統(tǒng)凈初級(jí)生產(chǎn)力(NPP),結(jié)合渦度相關(guān)觀測(cè)結(jié)果估算Ra和Rh[15- 17],但生物量調(diào)查和渦度相關(guān)觀測(cè)的時(shí)間尺度不一致,并且生物量調(diào)查法耗費(fèi)大量的人力物力,難以獲得持續(xù)的、高質(zhì)量觀測(cè)數(shù)據(jù)。第3種是基于過(guò)程機(jī)理模型模擬Ra和Rh,但該方法所需參數(shù)較多,結(jié)果也受到模型設(shè)計(jì)者對(duì)RE過(guò)程理解程度的限制[10]?；谕凰胤逐s比也可以實(shí)現(xiàn)對(duì)RE組分的拆分[18- 19],但所需儀器設(shè)備非常昂貴。Schwalm等[20]提出了基于通量觀測(cè)數(shù)據(jù)的統(tǒng)計(jì)學(xué)拆分方法,并對(duì)其不確定性進(jìn)行了分析。結(jié)果表明,該方法具有很好的穩(wěn)定性,不同參數(shù)方案間沒(méi)有明顯差異,這為利用通量觀測(cè)數(shù)據(jù)分析RE組分提供了新的技術(shù)途徑。

中國(guó)陸地生態(tài)系統(tǒng)通量觀測(cè)網(wǎng)絡(luò)(ChinaFLUX)自2002年建立以來(lái),已積累了大量的觀測(cè)數(shù)據(jù),構(gòu)建了學(xué)術(shù)界普遍認(rèn)可的通量數(shù)據(jù)處理流程[21]。然而,現(xiàn)有通量數(shù)據(jù)處理僅將生態(tài)系統(tǒng)碳通量分解為GPP和RE,尚沒(méi)有拆分RE的組分。因此,本研究利用Schwalm等[20]分析方法,拆分并評(píng)價(jià)我國(guó)典型森林和草地生態(tài)系統(tǒng)的RE組分及其相互關(guān)系,進(jìn)而闡明：(1)不同生態(tài)系統(tǒng)Ra和Rh的動(dòng)態(tài)特征,(2)Rh/RE的年內(nèi)動(dòng)態(tài)變化特征,(3)不同生態(tài)系統(tǒng)間Ra和Rh年總量的差異。該研究可以為生態(tài)系統(tǒng)碳循環(huán)過(guò)程研究提供基礎(chǔ)數(shù)據(jù),也為通量數(shù)據(jù)處理過(guò)程中RE拆分方法的確定提供依據(jù)。

1 研究地點(diǎn)與研究方法

1.1 站點(diǎn)介紹

本研究選擇ChinaFLUX中3個(gè)陸地生態(tài)系統(tǒng)為研究對(duì)象,分別為：長(zhǎng)白山溫帶針闊混交林(CBS)、鼎湖山亞熱帶常綠闊葉林(DHS)和海北高寒灌叢草甸(HBGC),各生態(tài)系統(tǒng)的基本信息如表1所示。

表1 研究站點(diǎn)基本信息

CBS：長(zhǎng)白山溫帶針闊混交林Changbai Mountains temperate conifer and broadleaf mixed forest；HBGC：海北灌叢草甸Haibei alpine Shrub；DHS：鼎湖山亞熱帶常綠闊葉林Dinghu Mountains subtropical evergreen broadleaf forest

3個(gè)生態(tài)系統(tǒng)均利用開(kāi)路式渦度相關(guān)系統(tǒng)(OPEC)進(jìn)行生態(tài)系統(tǒng)碳水通量觀測(cè),原始采樣頻率為10 Hz,通過(guò)數(shù)據(jù)采集器計(jì)算并儲(chǔ)存30 min的通量數(shù)據(jù)。同時(shí)觀測(cè)溫度、濕度、降水、輻射等氣象要素并計(jì)算30 min平均值儲(chǔ)存[21- 24]。此外,輔以靜態(tài)箱-氣相色譜法測(cè)定土壤呼吸,每隔7—10 d測(cè)定1次[25- 27]。

1.2 數(shù)據(jù)處理

1.2.1 通量數(shù)據(jù)處理

采用ChinaFLUX通用數(shù)據(jù)處理流程對(duì)30 min通量數(shù)據(jù)進(jìn)行處理[21],包括三次坐標(biāo)旋轉(zhuǎn)、WPL校正、儲(chǔ)存項(xiàng)計(jì)算及降水剔除、閾值剔除和方差剔除等,并根據(jù)Reichstein等[28]的方法確定夜間u*臨界值、實(shí)現(xiàn)夜間數(shù)據(jù)剔除、完成數(shù)據(jù)質(zhì)量控制。利用非線性回歸方法對(duì)碳通量數(shù)據(jù)進(jìn)行插補(bǔ),并將碳通量拆分為GPP和RE。

1.2.2 自養(yǎng)呼吸和異養(yǎng)呼吸的拆分

本研究根據(jù)自養(yǎng)呼吸與生態(tài)系統(tǒng)呼吸的比值(Ra/RE)對(duì)RE進(jìn)行拆分[20]。具體做法為：假設(shè)凈生態(tài)系統(tǒng)生產(chǎn)力(NEP)與RE的比值為θ,Ra/RE為β,則：

(1)

因而,根據(jù)式(1)可以得到β,即：

(2)

已有研究表明,NPP/GPP介于0.47—0.60之間[20],因而,β的范圍可以表示為：

(3)

在生態(tài)學(xué)研究中,Schwalm等[20]將Ra/RE或Rh/RE的最小值Ω設(shè)為0.10,并分析了Ω上下浮動(dòng)0.05后的結(jié)果,他發(fā)現(xiàn)基于不同Ω得到的β沒(méi)有明顯差異,因而此處Ω設(shè)為0.10。

當(dāng)β取最小值(0.10)時(shí),θ=-0.75；當(dāng)β取最大值(0.90)即Rh/RE取最小值(0.10)時(shí),θ=0.70。因而,θlt;-0.75或者θgt;0.70時(shí),公式(3)不再適用。當(dāng)θ=-0.75時(shí),βlower為0.10,βupper為0.13；當(dāng)θ=0.70時(shí),βlower為0.68,βupper為0.90。針對(duì)不同的θ值,設(shè)定不同的β范圍,具體范圍如表2所示。

表2 不同θ值下的β范圍

根據(jù)θ值,在β給定的范圍內(nèi)隨機(jī)選取1000個(gè)數(shù)據(jù),取其平均值為β。夜間時(shí),θ=-1,利用公式(3)無(wú)法獲取β值,因而將當(dāng)日白天最后一個(gè)有效的β和次日最早一個(gè)有效的β進(jìn)行線性內(nèi)插的方法獲取夜間β。

最后,根據(jù)β值和RE計(jì)算Ra和Rh,即：

Ra=β×RE
Rh=(1-β)×RE

(4)

1.3 生態(tài)系統(tǒng)呼吸拆分結(jié)果的驗(yàn)證

為了驗(yàn)證該方法的合理性,利用靜態(tài)箱-氣相色譜法觀測(cè)的土壤呼吸(Rs)數(shù)據(jù)與本研究獲取的Rh進(jìn)行對(duì)比。由于靜態(tài)箱-氣相色譜法的觀測(cè)時(shí)間是9：00—11:00,因此,Rh選用9:00—11:30的平均值。

1.4 數(shù)據(jù)統(tǒng)計(jì)

采用單因素方差分析法評(píng)價(jià)不同生態(tài)系統(tǒng)間RE組分的差異,采用線性回歸分析拆分結(jié)果與靜態(tài)箱-氣相色譜法所獲結(jié)果的差異。所有數(shù)據(jù)統(tǒng)計(jì)分析過(guò)程均在matlab7.7中進(jìn)行。

2 結(jié)果與分析

2.1 生態(tài)系統(tǒng)呼吸及其組分的季節(jié)動(dòng)態(tài)

生態(tài)系統(tǒng)碳通量具有明顯的季節(jié)變化特征[29- 31]。由于年際間生態(tài)系統(tǒng)的季節(jié)動(dòng)態(tài)特征相似[32- 34],本文以2003年數(shù)據(jù)為例分析中國(guó)典型森林和草地生態(tài)系統(tǒng)碳通量的季節(jié)動(dòng)態(tài)(圖1)。

圖1 2003年典型生態(tài)系統(tǒng)氣溫及碳通量的季節(jié)變化特征Fig.1 Seasonal dynamics of air temperature and carbon fluxes in typical ecosystems in 2003

氣溫(Ta)在3個(gè)典型生態(tài)系統(tǒng)均表現(xiàn)出單峰型變化(圖1),最大值出現(xiàn)在7月份前后,但不同生態(tài)系統(tǒng),其年內(nèi)氣溫的變化幅度存在明顯差異,DHS常年保持較高的氣溫,北方兩個(gè)生態(tài)系統(tǒng)(CBS和HBGC)年內(nèi)氣溫變幅較大。不同生態(tài)系統(tǒng),GPP的季節(jié)動(dòng)態(tài)有所差異(圖1),北方生態(tài)系統(tǒng)(CBS和HBGC)表現(xiàn)出明顯的單峰型特點(diǎn),但DHS的GPP在秋冬季節(jié)較高,在6—8月因溫度過(guò)高而略低,這與已有結(jié)果[23]相一致。NEP的季節(jié)動(dòng)態(tài)與GPP相似(圖1),但峰值出現(xiàn)時(shí)間較GPP略有提前。

3個(gè)生態(tài)系統(tǒng)的RE均表現(xiàn)出明顯的單峰型變化,峰值均出現(xiàn)在7—8月份(圖1),與氣溫的季節(jié)動(dòng)態(tài)(圖1)相似,這是因?yàn)?生態(tài)系統(tǒng)尺度上,氣溫的波動(dòng)決定了RE的季節(jié)動(dòng)態(tài)[35]。生態(tài)系統(tǒng)間,最大呼吸速率存在差異,CBS可以達(dá)到9.20 gC m-2d-1,DHS和HBGC明顯小于CBS,均不足4 gC m-2d-1。這主要是生產(chǎn)力的差異引起的,生產(chǎn)力與RE存在著密切的耦合關(guān)系[35- 37]。

與RE的動(dòng)態(tài)特征相似,Ra和Rh也表現(xiàn)出單峰型的季節(jié)動(dòng)態(tài)(圖1),峰值出現(xiàn)的時(shí)間也與RE相似,峰值大小約為RE峰值的一半。

2.2 生態(tài)系統(tǒng)呼吸組分與生態(tài)系統(tǒng)呼吸比值(Rh/RE和Ra/RE)的季節(jié)動(dòng)態(tài)

異養(yǎng)呼吸與生態(tài)系統(tǒng)呼吸的比值(Rh/RE)表現(xiàn)出明顯的季節(jié)波動(dòng),但在生態(tài)系統(tǒng)間表現(xiàn)出不同的變化特征(圖2)。

Rh/RE在CBS表現(xiàn)為年初和年末略低、生長(zhǎng)季開(kāi)始和結(jié)束時(shí)略有增加的趨勢(shì),在生長(zhǎng)旺盛時(shí)節(jié)大致維持在0.5左右,DHS全年均在0.5附近波動(dòng)。與兩個(gè)森林生態(tài)系統(tǒng)的變化趨勢(shì)不同,Rh/RE在HBGC表現(xiàn)出明顯的單峰型動(dòng)態(tài),非生長(zhǎng)季可以達(dá)到0.9,隨著生長(zhǎng)季的開(kāi)始,Rh/RE逐漸降低,并在生長(zhǎng)旺季達(dá)到0.5左右的最小值,隨著生長(zhǎng)季的結(jié)束,異養(yǎng)呼吸占據(jù)主導(dǎo),Rh/RE又開(kāi)始增大。

自養(yǎng)呼吸與生態(tài)系統(tǒng)呼吸的比值(Ra/RE)表現(xiàn)出與Rh/RE相反的季節(jié)變化趨勢(shì)。

圖2 2003年三個(gè)典型生態(tài)系統(tǒng)的生態(tài)系統(tǒng)呼吸組分在生態(tài)系統(tǒng)呼吸中所占比例(Rh/RE, Ra/RE)的季節(jié)動(dòng)態(tài)特征Fig.2 Seasonal dynamics of the ratio of autotrophic respiration and heterotrophic respiration to ecosystem respiration (Ra/RE, Rh/RE) in typical ecosystems in 2003

2.3 生態(tài)系統(tǒng)呼吸及其組分的年總量

生態(tài)系統(tǒng)呼吸的組分反映了生態(tài)系統(tǒng)消耗碳量的不同途徑。中國(guó)3個(gè)典型生態(tài)系統(tǒng)的RE及其組分的年總量如表3所示。

生態(tài)系統(tǒng)間,RE、Ra和Rh均存在顯著差異,均表現(xiàn)為CBS最高,DHS居中,HBGC最低。生態(tài)系統(tǒng)間Rh/RE的差異表現(xiàn)為：兩個(gè)森林生態(tài)系統(tǒng)(CBS和DHS)間沒(méi)有明顯差別,約為0.49,但顯著小于HBGC的0.60。Ra/RE表現(xiàn)出相反的特征,即HBGC的數(shù)值為0.40,明顯小于CBS和DHS的0.51。

表3 典型生態(tài)系統(tǒng)的生態(tài)系統(tǒng)呼吸及其組分的年總量

表中數(shù)據(jù)為2003—2005年的平均值,括號(hào)內(nèi)數(shù)值為2003—2005年的標(biāo)準(zhǔn)差

3 討論

3.1 生態(tài)系統(tǒng)呼吸拆分結(jié)果的不確定性

本研究采用的方法是Schwalm等[20]對(duì)加拿大森林RE進(jìn)行研究時(shí)提出的,目前尚沒(méi)有在其他生態(tài)系統(tǒng)中應(yīng)用。但相對(duì)于其他研究方法,本方法結(jié)構(gòu)簡(jiǎn)單、可操作性強(qiáng)并具有一定的生態(tài)學(xué)理論基礎(chǔ)。

理論上來(lái)說(shuō),當(dāng)NPP/GPP保持恒定的比值時(shí),Ra/RE隨著NEP/RE的增加而增大,即隨著NEP/RE的增加,RE中的Rh組分降低,從圖2可知,Ra/RE的變化與NEP的變化有相似的規(guī)律,這證實(shí)了該方法在理論上是可行的。

在理論分析的基礎(chǔ)上,用靜態(tài)箱-氣相色譜法觀測(cè)的Rs與本研究中拆分得到的Rh作對(duì)比(圖3),以驗(yàn)證該方法的拆分效果。

從圖3可以看出,在CBS,Rh與Rs的比值為0.34(圖3),這在之前研究結(jié)果[38- 39]的范圍內(nèi),并與東北林區(qū)其他研究[40]相似。在DHS和HBGC,Rh與Rs間沒(méi)有明顯的關(guān)系。這是因?yàn)?在CBS,利用箱式法觀測(cè)的Rs是生態(tài)系統(tǒng)呼吸的一部分(圖3),可以反映RE的動(dòng)態(tài),但在DHS和HBGC,箱式法觀測(cè)到的Rs幾乎與該時(shí)段的RE相一致,這可能是由箱式法本身觀測(cè)的誤差引起的。

進(jìn)一步整理了已發(fā)表文獻(xiàn)的NPP數(shù)據(jù),結(jié)合渦度相關(guān)觀測(cè)的碳通量結(jié)果,估算RE及其組分年總量間的相互關(guān)系。在CBS,張娜等[41]模擬發(fā)現(xiàn),1995年該生態(tài)系統(tǒng)Ra/RE高達(dá)0.82,高于本研究結(jié)果(表3),這可能是他們估算的NEP過(guò)高及NPP偏小導(dǎo)致的,NEP值高達(dá)392 gC m-2a-1[41],比渦度相關(guān)觀測(cè)結(jié)果[34]高54%。在DHS,2003—2004年的NPP為970 gC m-2a-1[42],結(jié)合Yu等[34]的結(jié)果可以看到,這兩年該生態(tài)系統(tǒng)的Ra/RE為52.33%,與本研究結(jié)果(表3)相似。

雖然Piao等[11]總結(jié)已有研究結(jié)果[1, 43- 44]發(fā)現(xiàn),Ra與GPP的比值雖然表現(xiàn)出隨著溫度的增加先降低后增大,但具有較大的變異性,基于本研究的方法,CBS、DHS、HBGC的Ra/GPP分別為0.40、0.31、0.35,也在Piao等[11]的范圍之內(nèi)。

因而,本研究所用方法具有簡(jiǎn)便易行、無(wú)需額外測(cè)定即可準(zhǔn)確拆分RE,這為分析碳收支組分及其影響因素提供了可能,可以在生態(tài)系統(tǒng)碳循環(huán)研究中應(yīng)用。

3.2 生態(tài)系統(tǒng)呼吸拆分結(jié)果對(duì)NPP/GPP的敏感性

本研究將NPP/GPP的值設(shè)為0.47—0.60,但Litton等[43]整理文獻(xiàn)數(shù)據(jù)發(fā)現(xiàn),NPP/GPP變異很大,最小甚至可能低于0.20。因而有必要進(jìn)一步分析NPP/GPP的變化對(duì)RE組分拆分的影響。

此處設(shè)定兩個(gè)方案,即將NPP/GPP(θ)的上下限(0.47—0.60)分別下調(diào)0.10(方案I)和上調(diào)0.10(方案II),相應(yīng)的RE/NEP(β)的臨界比值發(fā)生改變(表4)。

表4 不同處理方案下θ值下的β范圍

基于不同數(shù)據(jù)處理方案獲得了生態(tài)系統(tǒng)呼吸組分相互關(guān)系的季節(jié)動(dòng)態(tài)(圖4),Ra/RE及Rh/RE的季節(jié)動(dòng)態(tài)與圖2沒(méi)有明顯差異,說(shuō)明不同NPP/GPP的變化不會(huì)對(duì)Ra/RE及Rh/RE的季節(jié)動(dòng)態(tài)產(chǎn)生明顯影響。

圖4 2003年不同NPP/GPP的典型生態(tài)系統(tǒng)的生態(tài)系統(tǒng)呼吸組分在生態(tài)系統(tǒng)呼吸中所占比例(Rh/RE, Ra/RE)的季節(jié)動(dòng)態(tài)特征Fig.4 Seasonal dynamics of the ratio of autotrophic respiration and heterotrophic respiration to ecosystem respiration (Ra/RE, Rh/RE) in typical ecosystems in 2003 with different NPP/GPP

不同數(shù)據(jù)處理方案下,生態(tài)系統(tǒng)呼吸組分在生態(tài)系統(tǒng)呼吸中所占的比例發(fā)生一定的波動(dòng)(表5),NPP/GPP每改變0.1,Ra/RE變化0.05,Ra/RE隨著NPP/GPP的增加而降低。

表5不同數(shù)據(jù)處理方案生態(tài)系統(tǒng)呼吸組分在生態(tài)系統(tǒng)呼吸中所占比例

Table5Theratioofautotrophicrespirationandheterotrophicrespirationtoecosystemrespiration(Ra/RE, Rh/RE)underdifferentdatatreatments

處理Treatment自養(yǎng)呼吸與生態(tài)系統(tǒng)呼吸的比值Ra/RE長(zhǎng)白山CBS鼎湖山DHS海北灌叢HBGC異養(yǎng)呼吸與生態(tài)系統(tǒng)呼吸的比值Rh/RE長(zhǎng)白山CBS鼎湖山DHS海北灌叢HBGC本研究Thisstudy0．51(0．01)0．51(0．01)0．40(0．00)0．49(0．01)0．49(0．01)0．60(0．01)方案ⅠTreatmentⅠ0．56(0．01)0．55(0．01)0．43(0．01)0．44(0．01)0．45(0．02)0．57(0．01)方案ⅡTreatmentⅡ0．46(0．01)0．45(0．01)0．36(0．00)0．54(0．01)0．55(0．02)0．64(0．00)

表中數(shù)據(jù)為2003—2005年的平均值,括號(hào)內(nèi)數(shù)值為觀測(cè)期間的標(biāo)準(zhǔn)差

生態(tài)系統(tǒng)間,不管NPP/GPP發(fā)生何種變化,HBGC的Ra/RE均小于CBS和DHS,并且該值始終小于0.5,因而HBGC的生態(tài)系統(tǒng)呼吸以異養(yǎng)呼吸為主。隨著NPP/GPP的變化,CBS和DHS中Ra/RE在0.5上下浮動(dòng),表明森林生態(tài)系統(tǒng)中自養(yǎng)和異養(yǎng)呼吸所占的比例大致相似。

可見(jiàn),NPP/GPP影響著RE組分拆分,生物量調(diào)查獲取的NPP將為生態(tài)系統(tǒng)碳通量組分的拆分提供重要基礎(chǔ)數(shù)據(jù)。

3.3 生態(tài)系統(tǒng)呼吸各組分間的相互關(guān)系

在季節(jié)動(dòng)態(tài)上,Ra/RE隨著NEP的增加有增大的趨勢(shì)[20],表明隨著植物生長(zhǎng)的開(kāi)始,生態(tài)系統(tǒng)在不斷固碳的基礎(chǔ)上通過(guò)自養(yǎng)呼吸向外排放的碳量也在增加。這是因?yàn)镽a中的維持呼吸與溫度相關(guān),隨著溫度的增加呈指數(shù)增加[7]；生長(zhǎng)呼吸與溫度沒(méi)有直接關(guān)系,但與GPP呈一定的比例關(guān)系[8]；而Rh受土壤溫濕度和有機(jī)質(zhì)含量的影響。因此,在生長(zhǎng)季開(kāi)始后,隨著GPP和氣溫的增大,Ra增加速度快于Rh,導(dǎo)致Ra/RE開(kāi)始增加。

生態(tài)系統(tǒng)之間,Ra年總量與RE年總量的比值也明顯不同,森林生態(tài)系統(tǒng)明顯高于草地生態(tài)系統(tǒng),表明森林生態(tài)系統(tǒng)Ra所占比例高于草地生態(tài)系統(tǒng),與Schwalm等[20]的結(jié)果相同。這是因?yàn)?森林生態(tài)系統(tǒng)具有較高的NEP,NEP/RE也較高,導(dǎo)致Ra/RE高。比較中國(guó)與加拿大森林生態(tài)系統(tǒng)間[20]的Ra/RE的差異可以發(fā)現(xiàn),中國(guó)森林生態(tài)系統(tǒng)的Ra/RE明顯高于加拿大森林生態(tài)系統(tǒng),這也是由中國(guó)森林生態(tài)系統(tǒng)中NEP/RE高于加拿大所決定的。

4 結(jié)論

基于ChinaFLUX3個(gè)陸地生態(tài)系統(tǒng)(CBS：長(zhǎng)白山溫帶混交林,DHS：鼎湖山亞熱帶常綠闊葉林,HBGC：海北高寒灌叢草甸)的渦度相關(guān)觀測(cè)數(shù)據(jù),利用統(tǒng)計(jì)分析方法拆分了RE組分,分析了該方法在中國(guó)陸地生態(tài)系統(tǒng)的適用性及對(duì)NPP/GPP的敏感性,闡明了RE組分的動(dòng)態(tài)特征及其相互關(guān)系。結(jié)果表明：基于渦度相關(guān)觀測(cè)數(shù)據(jù)及NPP/GPP的比值,可以準(zhǔn)確拆分中國(guó)典型生態(tài)系統(tǒng)的RE,但該方法對(duì)NPP/GPP較為敏感。3個(gè)生態(tài)系統(tǒng)中,RE及其組分年內(nèi)均表現(xiàn)出單峰型的變化,在生長(zhǎng)旺盛時(shí)節(jié)(7月份)達(dá)到最大值。異養(yǎng)呼吸在生態(tài)系統(tǒng)呼吸中所占的比例(Rh/RE)表現(xiàn)出明顯的季節(jié)變化,CBS表現(xiàn)出先增大后減小的季節(jié)特征,DHS則常年維持為0.5左右,HBGC表現(xiàn)出先降低后增大的特點(diǎn)。年總量上,Rh/RE因生態(tài)系統(tǒng)的不同而不同,CBS和DHS兩個(gè)森林生態(tài)系統(tǒng)的自養(yǎng)和異養(yǎng)呼吸大致相當(dāng),HBGC的碳排放則主要通過(guò)異養(yǎng)呼吸來(lái)實(shí)現(xiàn)。該方法可以拆分RE組分,進(jìn)而為生態(tài)系統(tǒng)碳循環(huán)的過(guò)程研究提供參考數(shù)據(jù),但今后應(yīng)加強(qiáng)NPP/GPP的測(cè)定,以提高生態(tài)系統(tǒng)呼吸拆分的精度。

Referrences:

[1] Luyssaert S, Inglima I, Jung M, Richardson A D, Reichsteins M, Papale D, Piao S L, Schulzes E D, Wingate L, Matteucci G, Aragao L, Aubinet M, Beers C, Bernhoffer C, Black K G, Bonal D, Bonnefond J M, Chambers J, Ciais P, Cook B, Davis K J, Dolman A J, Gielen B, Goulden M, Grace J, Granier A, Grelle A, Griffis T, Grunwald T, Guidolotti G, Hanson P J, Harding R, Hollinger D Y, Hutyra L R, Kolar P, Kruijt B, Kutsch W, Lagergren F, Laurila T, Law B E, Le Maire G, Lindroth A, Loustau D, Malhi Y, Mateus J, Migliavacca M, Misson L, Montagnani L, Moncrieff J, Moors E, Munger J W, Nikinmaa E, Ollinger S V, Pita G, Rebmann C, Roupsard O, Saigusa N, Sanz M J, Seufert G, Sierra C, Smith M L, Tang J, Valentini R, Vesala T, Janssens I A. CO2balance of boreal, temperate, and tropical forests derived from a global database. Global Change Biology, 2007, 13(12): 2509- 2537.

[2] Davidson E A, Janssens I A, Luo Y Q. On the variability of respiration in terrestrial ecosystems: moving beyond Q10. Global Change Biology, 2006, 12(2): 154- 164.

[3] Houghton R A, Davidson E A, Woodwell G M. Missing sinks, feedbacks, and understanding the role of terrestrial ecosystems in the global carbon balance. Global Biogeochemical Cycles, 1998, 12(1): 25- 34.

[4] Cox P M, Betts R A, Jones C D, Spall S A, Totterdell I J. Acceleration of global warming due to carbon-cycle feedbacks in a coupled climate model. Nature, 2000, 408(6809): 184- 187.

[5] Yuan W P, Luo Y Q, Li X L, Liu S G, Yu G R, Zhou T, Bahn M, Black A, Desai A R, Cescatti A, Marcolla B, Jacobs C, Chen J Q, Aurela M, Bernhofer C, Gielen B, Bohrer G, Cook D R, Dragoni D, Dunn A L, Gianelle D, Grünwald T, Ibrom A, Leclerc M Y, Lindroth A, Liu H P, Marchesini L B, Montagnani L, Pita G, Rodeghiero M, Rodrigues A, Starr G, Stoy P C. Redefinition and global estimation of basal ecosystem respiration rate. Global Biogeochemical Cycles, 2011, 25: GB4002, doi: 10.1029/2011gb004150.

[6] Beer C, Reichstein M, Tomelleri E, Ciais P, Jung M, Carvalhais N, Rodenbeck C, Arain M A, Baldocchi D, Bonan G B, Bondeau A, Cescatti A, Lasslop G, Lindroth A, Lomas M, Luyssaert S, Margolis H, Oleson K W, Roupsard O, Veenendaal E, Viovy N, Williams C, Woodward F I, Papale D. Terrestrial gross carbon dioxide uptake: global distribution and covariation with climate. Science, 2010, 329(5993): 834- 838.

[7] Ryan M G. A simple method for estimating gross carbon budgets for vegetation in forest ecosystems. Tree Physiology, 1991, 9(1/2): 255- 266.

[8] Chen J M, Liu J, Cihlar J, Goulden M L. Daily canopy photosynthesis model through temporal and spatial scaling for remote sensing applications. Ecological Modelling, 1999, 124(2/3): 99- 119.

[9] Trumbore S. Carbon respired by terrestrial ecosystems-recent progress and challenges. Global Change Biology, 2006, 12(2): 141- 153.

[10] Yu G R. Scientific Frontier on Human Activities and Ecosystem Changes. Beijing: Higher Education Press, 2009.

[11] Piao S L, Luyssaert S, Ciais P, Janssens I A, Chen A P, Cao C, Fang J Y, Friedlingstein P, Luo Y Q, Wang S P. Forest annual carbon cost: a global-scale analysis of autotrophic respiration. Ecology, 2010, 91(3): 652- 661.

[12] Irvine J, Law B E, Martin J G, Vickers D. Interannual variation in soil CO2efflux and the response of root respiration to climate and canopy gas exchange in mature ponderosa pine. Global Change Biology, 2008, 14(12): 2848- 2859.

[13] Nagy Z, Pintér K, Pavelka M, Darenová E, Balogh J. Carbon fluxes of surfaces vs. ecosystems: advantages of measuring eddy covariance and soil respiration simultaneously in dry grassland ecosystems. Biogeosciences, 2011, 8(9): 2523- 2534.

[14] Griffis T J, Black T A, Gaumont-Guay D, Drewitt G B, Nesic Z, Barr A G, Morgenstern K, Kljun N. Seasonal variation and partitioning of ecosystem respiration in a southern boreal aspen forest. Agricultural and Forest Meteorology, 2004, 125(3/4): 207- 223.

[15] Law B E, Thornton P E, Irvine J, Anthoni P M, Van Tuyl S. Carbon storage and fluxes in ponderosa pine forests at different developmental stages. Global Change Biology, 2001, 7(7): 755- 777.

[16] Luyssaert S, Reichstein M, Schulze E D, Janssens I A, Law B E, Papale D, Dragoni D, Goulden M L, Granier A, Kutsch W L, Linder S, Matteucci G, Moors E, Munger J W, Pilegaard K, Saunders M, Falge E M. Toward a consistency cross-check of eddy covariance flux-based and biometric estimates of ecosystem carbon balance. Global Biogeochemical Cycles, 2009, 23: GB3009, doi: 10.1029/2008gb003377.

[17] Tan Z H, Zhang Y P, Yu G R, Sha L Q, Tang J W, Deng X B, Song Q H. Carbon balance of a primary tropical seasonal rain forest. Journal of Geophysical Research, 2010, 115: D00H26, doi: 10.1029/2009jd012913.

[18] Riveros-Iregui D A, Hu J, Burns S P, Bowling D R, Monson R K. An interannual assessment of the relationship between the stable carbon isotopic composition of ecosystem respiration and climate in a high-elevation subalpine forest. Journal of Geophysical Research, 2011, 116: G02005, doi: 10.1029/2010jg001556.

[19] Schuur E A G, Trumbore S E. Partitioning sources of soil respiration in boreal black spruce forest using radiocarbon. Global Change Biology, 2006, 12(2): 165- 176.

[20] Schwalm C R, Black T A, Morgenstern K, Humphreys E R. A method for deriving net primary productivity and component respiratory fluxes from tower-based eddy covariance data: a case study using a 17-year data record from a Douglas-fir chronosequence. Global Change Biology, 2007, 13(2): 370- 385.

[21] Yu G R, Fu Y L, Sun X M, Wen X F, Zhang L M. Recent progress and future directions of ChinaFLUX. Science in China Series D: Earth Sciences, 2006, 49(Suppl II): 1- 23.

[22] Zhang J H, Yu G R, Han S J, Guan D X, Sun X M. Seasonal and annual variation of CO2flux above a broad-leaved Korean pine mixed forest. Science in China Series D: Earth Sciences, 2006, 49(Suppl II): 63- 73.

[23] Wang C L, Yu G R, Zhou G Y, Yan J H, Zhang L M, Wang X, Tang X L, Sun X M. CO2flux evaluation over the evergreen coniferous and broad-leaved mixed forest in Dinghushan, China. Science in China Series D: Earth Sciences, 2006, 49(Suppl II): 127- 138.

[24] Li Y N, Sun X M, Zhao X Q, Zhao L, Xu S X, Gu S, Zhang G F, Yu G R. Seasonal variations and mechanism for environmental control of NEE of CO2concerning thePotentillafruticosain alpine shrub meadow of Qinghai-Tibet Plateau. Science in China Series D: Earth Sciences, 2006, 49(Suppl II): 174- 185.

[25] Zheng Z M, Yu G R, Sun X M, Cao G M, Wang Y S, Du M Y, Li J, Li Y N. Comparison of eddy covariance and static chamber/gas chromatogram methods in measuring ecosystem respiration. Chinese Journal of Applied Ecology, 2008, 19(2): 290- 298.

[26] Lin L S, Han S J, Wang Y S, Gu Z J. Soil CO2flux in several typical forests of Mt. Changbai. Chinese Journal of Ecology, 2004, 23(5): 42- 45.

[27] Zhang D Q, Sun X M, Zhou G Y, Yan J H, Wang Y S, Liu S Z, Zhou C Y, Liu J X, Tang X L, Li J, Zhang Q M. Seasonal dynamics of soil CO2effluxes with responses to environmental factors in lower subtropical forests of China. Science in China Series D: Earth Sciences, 2006, 49(Suppl II): 139- 149.

[28] Reichstein M, Falge E, Baldocchi D, Papale D, Aubinet M, Berbigier P, Bernhofer C, Buchmann N, Gilmanov T, Granier A, Grunwald T, Havrankova K, Ilvesniemi H, Janous D, Knohl A, Laurila T, Lohila A, Loustau D, Matteucci G, Meyers T, Miglietta F, Ourcival J M, Pumpanen J, Rambal S, Rotenberg E, Sanz M, Tenhunen J, Seufert G, Vaccari F, Vesala T, Yakir D, Valentini R. On the separation of net ecosystem exchange into assimilation and ecosystem respiration: review and improved algorithm. Global Change Biology, 2005, 11(9): 1424- 1439.

[29] Law B E, Williams M, Anthoni P M, Baldocchi D D, Unsworth M H. Measuring and modelling seasonal variation of carbon dioxide and water vapour exchange of aPinusponderosaforest subject to soil water deficit. Global Change Biology, 2000, 6(6): 613- 630.

[30] Valentini R, Gamon J A, Field C B. Ecosystem ags-exchange in a California grassland-seasonal patterns and implications for scaling. Ecology, 1995, 76(6): 1940- 1952.

[31] Guan D X, Wu J B, Zhao X S, Han S J, Yu G R, Sun X M, Jin C J. CO2fluxes over an old, temperate mixed forest in northeastern China. Agricultural and Forest Meteorology, 2006, 137(3/4): 138- 149.

[32] Barr A G, Black T A, Hogg E H, Griffis T J, Morgenstern K, Kljun N, Theede A, Nesic Z. Climatic controls on the carbon and water balances of a boreal aspen forest, 1994—2003. Global Change Biology, 2007, 13(3): 561- 576.

[33] Polley H W, Frank A B, Sanabria J, Phillips R L. Interannual variability in carbon dioxide fluxes and flux-climate relationships on grazed and ungrazed northern mixed-grass prairie. Global Change Biology, 2008, 14(7): 1620- 1632.

[34] Yu G R, Zhang L M, Sun X M, Fu Y L, Wen X F, Wang Q F, Li S G, Ren C Y, Song X, Liu Y F, Han S J, Yan J H. Environmental controls over carbon exchange of three forest ecosystems in eastern China. Global Change Biology, 2008, 14(11): 2555- 2571.

[35] Wen X F, Wang H M, Wang J L, Yu G R, Sun X M. Ecosystem carbon exchanges of a subtropical evergreen coniferous plantation subjected to seasonal drought, 2003—2007. Biogeosciences, 2010, 7(1): 357- 369.

[36] Wang X C, Wang C K, Yu G R. Spatio-temporal patterns of forest carbon dioxide exchange based on global eddy covariance measurements. Science in China Series D: Earth Sciences, 2008, 51(8): 1129- 1143.

[37] Lasslop G, Reichstein M, Detto M, Richardson A D, Baldocchi D D. Comment on Vickers et al.: self-correlation between assimilation and respiration resulting from flux partitioning of eddy-covariance CO2fluxes. Agricultural and Forest Meteorology, 2010, 150(2): 312- 314.

[38] Subke J A, Inglima I, Francesca Cotrufo M. Trends and methodological impacts in soil CO2efflux partitioning: a metaanalytical review. Global Change Biology, 2006, 12(6): 921- 943.

[39] Zhan X Y, Yu G R, Zheng Z M, Wang Q F. Carbon emission and spatial pattern of soil respiration of terrestrial ecosystems in China: based on geostatistic estimation of flux measurement. Progress in Geography, 2012, 31(1): 97- 108.

[40] Wang C K, Yang J Y. Rhizospheric and heterotrophic components of soil respiration in six Chinese temperate forests. Global Change Biology, 2007, 13(1): 123- 131.

[41] Zhang N, Yu G R, Zhao S D, Yu Z L. Carbon budget of ecosystem in Changbai Mountain natural reserve. Environmental Science, 2003, 24(1): 24- 32.

[42] Yan J H, Wang Y P, Zhou G Y, Zhang D Q. Estimates of soil respiration and net primary production of three forests at different succession stages in South China. Global Change Biology, 2006, 12(5): 810- 821.

[43] Litton C M, Raich J W, Ryan M G. Carbon allocation in forest ecosystems. Global Change Biology, 2007, 13(10): 2089- 2109.

[44] DeLucia E H, Drake J E, Thomas R B, Gonzalez-Meler M. Forest carbon use efficiency: is respiration a constant fraction of gross primary production?. Global Change Biology, 2007, 13(6): 1157- 1167.

[10] 于貴瑞. 人類活動(dòng)與生態(tài)系統(tǒng)變化的前沿科學(xué)問(wèn)題. 北京: 高等教育出版社, 2009.

[25] 鄭澤梅, 于貴瑞, 孫曉敏, 曹廣民, 王躍思, 杜明遠(yuǎn), 李俊, 李英年. 渦度相關(guān)法和靜態(tài)箱/氣相色譜法在生態(tài)系統(tǒng)呼吸觀測(cè)中的比較. 應(yīng)用生態(tài)學(xué)報(bào), 2008, 19(2): 290- 298.

[26] 林麗莎, 韓士杰, 王躍思, 谷志靜. 長(zhǎng)白山四種林分土壤CO2釋放通量的研究. 生態(tài)學(xué)雜志, 2004, 23(5): 42- 45.

[39] 展小云, 于貴瑞, 鄭澤梅, 王秋鳳. 中國(guó)區(qū)域陸地生態(tài)系統(tǒng)土壤呼吸的碳排放及空間格局——基于通量觀測(cè)的地學(xué)統(tǒng)計(jì)評(píng)估. 地理科學(xué)進(jìn)展, 2012, 31(1): 97- 108.

[41] 張娜, 于貴瑞, 趙士洞, 于振良. 長(zhǎng)白山自然保護(hù)區(qū)生態(tài)系統(tǒng)碳平衡研究. 環(huán)境科學(xué), 2003, 24(1): 24- 32.

Theinteractionbetweencomponentsofecosystemrespirationintypicalforestandgrasslandecosystems

ZHU Xianjin1,2, YU Guirui1, *, WANG Qiufeng1, GAO Yanni1,2, ZHAO Xinquan3, HAN Shijie4, YAN Junhua5

1SynthesisResearchCenterofCERN,KeyLaboratoryofEcosystemNetworkObservationandModeling,InstituteofGeographicSciencesandNaturalResourcesResearch,ChineseAcademyofSciences,Beijing100101,China2UniversityofChineseAcademyofSciences,Beijing100049,China3NorthwestPlateauInstituteofBiology,ChineseAcademyofSciences,Xining810001,China4InstituteofAppliedEcology,ChineseAcademyofSciences,Shenyang110016,China5SouthChinaBotanicalGarden,ChineseAcademyofSciences,Guangzhou510650,China

Ecosystem respiration (RE), the release of carbon from an ecosystem into the atmosphere, is a key component of the terrestrial ecosystem carbon budget and plays an important role in the global carbon balance. Analyzing the interaction between RE components is essential to understand RE and to accurately evaluate the ecosystem carbon budget. There are many methods for separating RE into autotrophic respiration (Ra) and heterotrophic respiration (Rh), but each approach has disadvantages. Large RE data have obtained through long-term eddy covariance measurements, while the interaction between Ra and Rh is poorly documented, which inhibits the accurate assessment of global carbon budget. In this study, we used an empirical statistical method to separate RE into its two components and to examine component relationships and seasonal dynamics at three ChinaFLUX sites: 1) Changbaishan temperate mixed forest (CBS); 2) Dinghushan subtropical evergreen broad-leaf forest (DHS); and 3) Haibei shrub meadow (HBGC). The applicability and sensitivity of this method in typical ecosystems of China were also evaluated. The method used in this study was based on the ratio of Ra to RE (Ra/RE). The range of Ra/RE was obtained by calculating two ratios: the ratio of RE to net ecosystem productivity (NEP) (RE/NEP) and that of net primary productivity (NPP) to gross primary productivity (GPP) (NPP/GPP). Within the range of Ra/RE, 1000 Ra/REs were randomly selected and the value of Ra/RE used in this study was set as the mean of the 1000 random Ra/REs. Ra and Rh were then calculated using Ra/RE and RE.

Our study showed that the RE separating method produced consistent results with those obtained through static chamber/gas chromatographic techniques at the same sites, as well as with biomass surveys and theoretical speculation. The interaction of RE components was sensitive to the variation of NPP/GPP: a ten-percent increase of NPP/GPP led to a five-percent decrease of Ra/RE. In all three ecosystems, RE and its components showed similar seasonal dynamics, with a single-peak pattern achieving its maximum midway through the growing season. The ratio of Rh to RE (Rh/RE) also showed different seasonal dynamic among the three ecosystems. In CBS, Rh/RE increased during the first half of the year, reached its peak during the growing season then decreased. However, Rh/RE in HBGC decreased during the first half of the year and increased again later in growing-season. In DHS, Rh/RE was relatively stable at approximately 0.5. Seasonal dynamics of Ra/RE were opposite to those in Rh/RE. The annual total Rh accounted for 60% of the RE in HBGC, suggesting that a large proportion of emitted carbon was released by Rh in this ecosystem. In CBS and DHS, Rh was only 49% of RE, indicating that the release of carbon through Ra and Rh was nearly the same in these two forest ecosystems. Results indicate that this statistical method, which requires detailed observations of NPP/GPP, can successfully separate RE into Rh and Ra and can provide necessary data for the detailed analysis of the ecosystem carbon cycle.

terrestrial ecosystem; ecosystem respiration; eddy covariance; carbon fluxes; autotrophic respiration; heterotrophic respiration

國(guó)家重點(diǎn)基礎(chǔ)研究發(fā)展規(guī)劃資助項(xiàng)目(2010CB833504); 國(guó)家自然科學(xué)基金資助項(xiàng)目(31061140359, 30590380); 中國(guó)科學(xué)院戰(zhàn)略性先導(dǎo)科技專項(xiàng)資助項(xiàng)目(XDA05050601)

2012- 07- 13;

2013- 06- 21

*通訊作者Corresponding author.E-mail: yugr@igsnrr.ac.cn

10.5846/stxb201207130988

朱先進(jìn),于貴瑞,王秋鳳,高艷妮,趙新全,韓士杰,閆俊華.典型森林和草地生態(tài)系統(tǒng)呼吸各組分間的相互關(guān)系.生態(tài)學(xué)報(bào),2013,33(21):6925- 6934.

Zhu X J, Yu G R, Wang Q F, Gao Y N, Zhao X Q, Han S J, Yan J H.The interaction between components of ecosystem respiration in typical forest and grassland ecosystems.Acta Ecologica Sinica,2013,33(21):6925- 6934.