The importance of hydrology in routing terrestrial carbon to the atmosphere via global streams and rivers.
The importance of hydrology in routing terrestrial carbon to the atmosphere via global streams and rivers.
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DOI：
10.1073/pnas.2106322119
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发表时间：
2022-03-15
影响因子：
11.1
通讯作者：
Raymond PA
中科院分区：
文献类型：
--
作者：
Liu S;Kuhn C;Amatulli G;Aho K;Butman DE;Allen GH;Lin P;Pan M;Yamazaki D;Brinkerhoff C;Gleason C;Xia X;Raymond PA
溪流/河流二氧化碳(CO2)排放具有显着的空间和季节变化，对于了解其宏观生态系统控制和陆地碳收支至关重要。我们依靠直接的河流二氧化碳分压测量以及随季节变化的气体传输速度和河网表面积估计来解决全球范围内达到水平的通量的季节性变化。分流到河流中的陆地初级生产力(GPP)的比例随着跨区域排放的增加而增加，这是因为河流中的CO2逃避对排放的响应比GPP更强。这突出了水文学的重要性，特别是水的吞吐量在陆地-河流碳转移中的重要性，以及在维持陆地碳收支时考虑这一影响的必要性。河流和河流二氧化碳(CO2)排放量的大小受流域生物地球化学和水文学季节性变化的影响。然而，全球对这一通量的估计是不确定的，依赖于二氧化碳的计算值，并且缺乏空间精度或季节变化，这对于理解通量的宏观生态系统控制至关重要。在这里，我们汇编了5,910个河流二氧化碳分压的直接测量结果，并根据流域特性对它们进行建模，以解决河流尺度下通量的月变化。然后，将直接测量与季节解析的气体传输速度和来自最近的全球水文数据集的河流表面积估计相结合，以限制每月尺度上的流量。在全球范围内，河流二氧化碳的排放量每月在112至209 Tg之间变化。北极和北温带河流的月流量变化比热带和南温带河流大得多(变异系数：46-95比6-12%)。每年河流二氧化碳排放量与陆地初级生产总值(GPP)的比率在不同地区之间差异很大，从微不足道的0.2%到18%不等。非线性回归表明，GPP呈饱和增长，跨区域排放的河流二氧化碳排放量呈非饱和、陡峭增长，这导致更高比例的GPP被分流到河流中，以躲避更潮湿的地区。这突出了水文学的重要性，特别是在通过全球排水网络将陆地碳输送到大气层方面。我们的结果表明，在估算陆地碳收支时，需要考虑陆地-大气和河流-大气碳交换的不同水文响应。
Stream/river carbon dioxide (CO2) emission has significant spatial and seasonal variations critical for understanding its macroecosystem controls and plumbing of the terrestrial carbon budget. We relied on direct fluvial CO2 partial pressure measurements and seasonally varying gas transfer velocity and river network surface area estimates to resolve reach-level seasonal variations of the flux at the global scale. The percentage of terrestrial primary production (GPP) shunted into rivers that ultimately contributes to CO2 evasion increases with discharge across regions, due to a stronger response in fluvial CO2 evasion to discharge than GPP. This highlights the importance of hydrology, in particular water throughput, in terrestrial–fluvial carbon transfers and the need to account for this effect in plumbing the terrestrial carbon budget. The magnitude of stream and river carbon dioxide (CO2) emission is affected by seasonal changes in watershed biogeochemistry and hydrology. Global estimates of this flux are, however, uncertain, relying on calculated values for CO2 and lacking spatial accuracy or seasonal variations critical for understanding macroecosystem controls of the flux. Here, we compiled 5,910 direct measurements of fluvial CO2 partial pressure and modeled them against watershed properties to resolve reach-scale monthly variations of the flux. The direct measurements were then combined with seasonally resolved gas transfer velocity and river surface area estimates from a recent global hydrography dataset to constrain the flux at the monthly scale. Globally, fluvial CO2 emission varies between 112 and 209 Tg of carbon per month. The monthly flux varies much more in Arctic and northern temperate rivers than in tropical and southern temperate rivers (coefficient of variation: 46 to 95 vs. 6 to 12%). Annual fluvial CO2 emission to terrestrial gross primary production (GPP) ratio is highly variable across regions, ranging from negligible (<0.2%) to 18%. Nonlinear regressions suggest a saturating increase in GPP and a nonsaturating, steeper increase in fluvial CO2 emission with discharge across regions, which leads to higher percentages of GPP being shunted into rivers for evasion in wetter regions. This highlights the importance of hydrology, in particular water throughput, in routing terrestrial carbon to the atmosphere via the global drainage networks. Our results suggest the need to account for the differential hydrological responses of terrestrial–atmospheric vs. fluvial–atmospheric carbon exchanges in plumbing the terrestrial carbon budget.
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影响因子：
16.6
作者：
Allen GH;Pavelsky TM;Barefoot EA;Lamb MP;Butman D;Tashie A;Gleason CJ
通讯作者：
Gleason CJ
影响因子：
20.6
作者：
Ciais P;Yao Y;Gasser T;Baccini A;Wang Y;Lauerwald R;Peng S;Bastos A;Li W;Raymond PA;Canadell JG;Peters GP;Andres RJ;Chang J;Yue C;Dolman AJ;Haverd V;Hartmann J;Laruelle G;Konings AG;King AW;Liu Y;Luyssaert S;Maignan F;Patra PK;Peregon A;Regnier P;Pongratz J;Poulter B;Shvidenko A;Valentini R;Wang R;Broquet G;Yin Y;Zscheischler J;Guenet B;Goll DS;Ballantyne AP;Yang H;Qiu C;Zhu D
通讯作者：
Zhu D
影响因子：
5.4
作者：
Brooks, Paul D.;Troch, Peter A.;Schlegel, Melissa
通讯作者：
Schlegel, Melissa
影响因子：
7.4
作者：
DAVISON, W;WOOF, C
通讯作者：
WOOF, C
影响因子：
18.3
作者：
Battin, Tom J.;Kaplan, Louis A.;Sabater, Francesc
通讯作者：
Sabater, Francesc