Modeling sediment diagenesis processes on riverbed to better quantify aquatic carbon fluxes and stocks in a small watershed of the Mid-Atlantic region

IF 3.9 3区环境科学与生态学 Q2 ENVIRONMENTAL SCIENCES

Carbon Balance and Management Pub Date : 2020-07-06 DOI:10.1186/s13021-020-00148-1

Junyu Qi, Xuesong Zhang, Sangchul Lee, Yiping Wu, Glenn E. Moglen, Gregory W. McCarty

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引用次数: 11

Abstract

Despite the widely recognized importance of aquatic processes for bridging gaps in the global carbon cycle, there is still a lack of understanding of the role of riverbed processes for carbon flows and stocks in aquatic environments. Here, we added a sediment diagenesis and sediment carbon (C) resuspension module into the SWAT-C model and tested it for simulating both particulate organic C (POC) and dissolved organic C (DOC) fluxes using 4?years of monthly observations (2014–2017) in the Tuckahoe watershed (TW) in the U.S. Mid-Atlantic region.

Sensitivity analyses show that parameters that regulate POC deposition in river networks are more sensitive than those that determine C resuspension from sediments. Further analyses indicate that allochthonous contributions to POC and DOC are about 36.6 and 46?kgC?ha^?1?year^?1, respectively, while autochthonous contributions are less than 0.72?kgC?ha^?1?year^?1 for both POC and DOC (less than 2% of allochthonous sources). The net deposition of POC on the riverbed (i.e., 11.4?kgC?ha^?1?year^?1) retained ca. 31% of terrestrial inputs of POC. In addition, average annual buried C was 0.34?kgC?ha^?1?year^?1, accounting for only 1% of terrestrial POC inputs or 3% of net POC deposition. The results indicate that about 79% of deposited organic C was converted to inorganic C (CH₄ and CO₂) in the sediment and eventually released into the overlying water column.

This study serves as an exploratory study on estimation of C fluxes from terrestrial to aquatic environments at the watershed scale. We demonstrated capabilities of the SWAT-C model to simulate C cycling from uplands to riverine ecosystems and estimated C sinks and sources in aquatic environments. Overall, the results highlight the importance of including carbon cycle dynamics within the riverbed in order to accurately estimate aquatic carbon fluxes and stocks. The new capabilities of SWAT-C are expected to serve as a useful tool to account for those processes in watershed C balance assessment.

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中大西洋地区小流域河床沉积成岩过程模拟，以更好地量化水生碳通量和储量

尽管人们普遍认识到水生过程在弥合全球碳循环缺口方面的重要性，但人们仍然缺乏对河床过程在水生环境中碳流动和储量中的作用的了解。在此，我们在SWAT-C模型中加入了沉积物成岩作用和沉积物碳(C)再悬浮模块，并使用4?2014-2017年美国中大西洋地区图卡霍流域(TW)的月度观测数据。敏感性分析表明，调节河网中POC沉积的参数比决定沉积物中C再悬浮的参数更敏感。进一步分析表明，外来对POC和DOC的贡献分别约为36.6和46 kgC / ha /年。而本地贡献小于0.72 kgC / ha / 1年。POC和DOC均为1(低于2%的外来来源)。POC在河床上的净沉积(即11.4 kgC / ha /年)保留了约31%的陆地输入POC。此外，年平均埋碳量为0.34 kgC / ha /年。1，仅占陆地POC输入的1%或净POC沉积的3%。结果表明，沉积物中约79%的有机C转化为无机C (CH4和CO2)，并最终释放到上覆水柱中。本研究是在流域尺度上估算陆地到水生环境碳通量的探索性研究。我们展示了SWAT-C模型模拟从高地到河流生态系统的碳循环的能力，并估计了水生环境中的碳汇和碳源。总体而言，研究结果强调了在河床内纳入碳循环动态的重要性，以便准确估计水生碳通量和储量。SWAT-C的新功能有望成为解释流域C平衡评估中这些过程的有用工具。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Carbon Balance and Management Environmental Science-Management, Monitoring, Policy and Law

CiteScore

7.60

自引率

0.00%

发文量

审稿时长

14 weeks

期刊介绍： Carbon Balance and Management is an open access, peer-reviewed online journal that encompasses all aspects of research aimed at developing a comprehensive policy relevant to the understanding of the global carbon cycle. The global carbon cycle involves important couplings between climate, atmospheric CO2 and the terrestrial and oceanic biospheres. The current transformation of the carbon cycle due to changes in climate and atmospheric composition is widely recognized as potentially dangerous for the biosphere and for the well-being of humankind, and therefore monitoring, understanding and predicting the evolution of the carbon cycle in the context of the whole biosphere (both terrestrial and marine) is a challenge to the scientific community. This demands interdisciplinary research and new approaches for studying geographical and temporal distributions of carbon pools and fluxes, control and feedback mechanisms of the carbon-climate system, points of intervention and windows of opportunity for managing the carbon-climate-human system. Carbon Balance and Management is a medium for researchers in the field to convey the results of their research across disciplinary boundaries. Through this dissemination of research, the journal aims to support the work of the Intergovernmental Panel for Climate Change (IPCC) and to provide governmental and non-governmental organizations with instantaneous access to continually emerging knowledge, including paradigm shifts and consensual views.