Network-scale streamflow intermittence controls on dissolved organic carbon concentrations and processes

对溶解有机碳浓度和过程的网络规模水流间歇控制

• 批准号: 1935839
• 负责人: Rebecca Hale
• 金额: $ 20万
• 依托单位: Idaho State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-07-01 至 2023-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1935839&HistoricalAwards=false
• 关键词: Network; scale; streamflow; intermittence; controls

Streams are important in the cycling of carbon. Almost half of the carbon in watersheds enter streams and rivers where it is converted to a carbon gas or transported downstream. Understanding of these processes come largely from studying continually flowing streams and rivers. Nearly 60% of streams in the United States are intermittent or ephemeral, and all stream and river networks have intermittent streamflow in their contributing networks. Yet little is known about the role that these periodically dry streams play in the processing and movement of carbon through the stream network. This award will address the question of how and when do spatial and temporal patterns of intermittence affect carbon concentrations and characteristics. The researchers will explore flow intermittence effects on dissolved organic carbon and the relative influence of legacy effects of drying during conditions when instream processes control dissolved organic carbon (e.g., growing season) and via connectivity to terrestrial sources during conditions when dissolved organic carbon is typically controlled by flow (e.g., high flows). The broader impacts include training of students, working with local watershed managers, coordinating with research networks, and producing a museum exhibit.Network scale approaches to understanding stream carbon cycling often make assumptions that are not appropriate for intermittent networks (e.g., homogeneous instream processing rates), and continental and global assessments of stream carbon cycling ignore the role of these streams, potentially missing a major component of the global carbon cycle. This award will transform approaches to thinking about streamflow intermittence and its effects on carbon cycling and transport by integrating network thinking and intermittency effects on biogeochemistry. This award will develop the conceptual and empirical basis for understanding when, where, and how streamflow intermittence affects instream process rates, connectivity to upstream carbon sources, and carbon concentrations and export. The research has two specific aims: Aim 1: Assess spatial and temporal effects of streamflow intermittence on spatial patterns of dissolved organic carbon. This will be accomplished through combining spatially extensive continuous flow presence/absence monitoring with detailed synoptic characterization of dissolved organic carbon concentrations and characteristics across an intermittent stream network. Aim 2: Assess how and when intermittence affects instream process rates and instream process controls on dissolved organic carbon concentrations. The researchers will use high-frequency monitoring of streamflow, dissolved organic carbon concentrations, and instream metabolism. The research will lay the groundwork for integrating heterogeneity into network models of stream carbon cycling.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

溪流在碳循环中很重要。流域中几乎一半的碳进入溪流和河流，在那里转化为碳气体或输送到下游。对这些过程的理解主要来自于对不断流动的溪流和河流的研究。美国近 60% 的溪流是间歇性或短暂性的，所有溪流和河流网络的贡献网络中都有间歇性的水流。然而，人们对这些周期性干燥的溪流在碳通过溪流网络的加工和移动中所发挥的作用知之甚少。该奖项将解决间歇性的空间和时间模式如何以及何时影响碳浓度和特征的问题。研究人员将探索流动间歇性对溶解有机碳的影响，以及在河流过程控制溶解有机碳的条件下（例如生长季节）干燥遗留效应的相对影响，以及在通常控制溶解有机碳的条件下通过与陆地来源的连接按流量（例如，高流量）。更广泛的影响包括培训学生、与当地流域管理者合作、与研究网络协调以及制作博物馆展览。理解河流碳循环的网络规模方法经常做出不适合间歇性网络的假设（例如，同质的河流处理速率） ），大陆和全球对河流碳循环的评估忽略了这些河流的作用，可能遗漏了全球碳循环的一个主要组成部分。该奖项将通过整合网络思维和生物地球化学的间歇性影响，改变对水流间歇性及其对碳循环和运输影响的思考方法。该奖项将为理解水流间歇性何时、何地以及如何影响河内过程速率、与上游碳源的连通性以及碳浓度和出口奠定概念和经验基础。该研究有两个具体目标： 目标 1：评估水流间歇性对溶解有机碳空间格局的空间和时间影响。这将通过将空间广泛的连续流存在/不存在监测与间歇流网络中溶解的有机碳浓度和特征的详细天气特征相结合来实现。目标 2：评估间歇性如何以及何时影响流内过程速率以及对溶解有机碳浓度的流内过程控制。研究人员将对水流、溶解有机碳浓度和河内代谢进行高频监测。该研究将为将异质性整合到河流碳循环网络模型中奠定基础。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

Non-perennial stream networks as directed acyclic graphs: The R-package streamDAG

作为有向无环图的非常年流网络：R 包streamDAG

• DOI: 10.1016/j.envsoft.2023.105775
• 发表时间: 2023-09-01
• 期刊: Environ. Model. Softw.
• 作者: Ken Aho;C. Kriloff;S. Godsey;Rob Ramos;Chris Wheeler;Y. You;S. Warix;D. Derryberry;S. Zipper;R. Hale;Charles T. Bond;K. Kuehn
• 通讯作者: K. Kuehn