A Terrestrial‐Aquatic Model Reveals Cross‐Scale Interactions Regulate Lateral Dissolved Organic Carbon Transport From Terrestrial Ecosystems
A Terrestrial‐Aquatic Model Reveals Cross‐Scale Interactions Regulate Lateral Dissolved Organic Carbon Transport From Terrestrial Ecosystems
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DOI：
10.1029/2021jg006604
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发表时间：
2022-05
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影响因子：
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通讯作者：
C. Talbot;D. Bolster;D. Medvigy;Stuart E. Jones
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作者：
C. Talbot;D. Bolster;D. Medvigy;Stuart E. Jones
横向碳迁移（LCT），即陆地碳通量输送到水生生态系统，在陆地-水生连续体中取代碳（C），并且与陆地净生态系统生产处于同一数量级。然而，很少有大陆尺度的 C 模型包含 LCT 或 LCT 建模所需的 C 水文联系。那些确实存在的模型借鉴了分水岭规模模型的流程和概念理解，假设 LCT 的大规模和小规模驱动因素是相同的。我们开发了 LCT 的概念框架，重点关注横向溶解有机碳（DOC）传输（LCT-DOC），并通过陆地-水生碳和水文耦合模型对其进行操作。将我们的 LCT-DOC 模型与之前根据美国本土景观尺度通量总和得出的估计进行比较后，我们使用模型实验来划分 LCT-DOC 驱动因素的重要性，包括年总降水量、气温和植物性状，这些因素在区域和地方尺度上相互作用。我们发现气候是 LCT-DOC 的最强驱动因素，其中 LCT-DOC 与降水量呈正相关，但与大陆尺度的温度呈负相关。然而，气候对 LCT-DOC 的净影响是气候和植被之间跨尺度相互作用的产物。植物性状还与气候产生强烈的相互作用，并对 LCT-DOC 有可测量的影响，其中水分利用效率是最有影响力的植物性状，因为它与陆地水和碳循环相结合。我们证明了我们的概念框架和相对简单的 LCT-DOC 链接 C-水文学过程模型可以为假设提供信息并预测 LCT-DOC。
Lateral carbon transport (LCT), the flux of terrestrial C transported to aquatic ecosystems, displaces carbon (C) across the terrestrial‐aquatic continuum and is on the same order of magnitude as terrestrial net ecosystem production. However, few continental scale C models include LCT or the C‐hydrology linkages necessary for modeling LCT. Those that do exist, borrow processes and conceptual understanding from watershed scale models, assuming that large‐scale and small‐scale drivers of LCT are the same. We develop a conceptual framework of LCT, which focuses on lateral dissolved organic carbon (DOC) transport (LCT‐DOC), and operationalize it with a coupled terrestrial‐aquatic C and hydrology model. After comparing our model LCT‐DOC to previous estimates derived from a summation of landscape scale fluxes for the Contiguous U.S., we use model experiments to partition the importance of LCT‐DOC drivers including total annual precipitation, air temperature, and plant traits, which interact across regional and local scales. We find that climate is the strongest driver of LCT‐DOC, where LCT‐DOC is positively related to precipitation but inversely related to temperature at continental scales. However, the net effect of climate on LCT‐DOC is the product of cross‐scale interactions between climate and vegetation. Plant traits also interact strongly with climate and have a measurable influence on LCT‐DOC, with water use efficiency as the most influential plant trait because it couples terrestrial water and C cycling. We demonstrate that our conceptual framework and relatively simple linked C‐hydrology process model of LCT‐DOC can inform hypotheses and predict LCT‐DOC.