Collaborative Research: Deciphering drivers and variability in salt marsh lateral carbon export

合作研究：破译盐沼横向碳输出的驱动因素和变异性

• 批准号: 2242114
• 负责人: Joseph Tamborski
• 金额: $ 49.92万
• 依托单位: Old Dominion University Research Foundation
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-08-01 至 2026-07-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2242114&HistoricalAwards=false
• 关键词: Collaborative; Research; Deciphering; drivers; variability

Tidal wetlands remove large amounts of carbon dioxide from the atmosphere. Some portion of this carbon is buried as soil, often referred to as “blue carbon.” However, another portion of this carbon is exported to the coastal ocean through tidal flushing of wetland sediments. The amount of carbon exported from tidal marshes is not well known. This project investigates the processes that control carbon exports from salt marshes using state-of-the-art methods. The overarching goal of this study is to develop the first predictive model of carbon exports. This model will provide a tool for predicting future changes in coastal carbon budgets with continued sea level rise. Inclusion of lateral carbon exports as a “blue carbon” sink would greatly increase the inventory of tidal wetland carbon sinks and add to the suite of ecosystem services that are preserved through conservation and restoration of wetlands. This project will train two PhD students and provide research opportunities for multiple undergraduate students. The researchers will participate in local outreach activities to increase awareness of the science related to this project.Lateral carbon (C) exports are thought to greatly exceed C burial globally, and by as much as a factor of five along the eastern coast of North America. However, these estimates are based on limited data. At present the mechanistic drivers and environmental variables that control lateral C and total alkalinity (TA) fluxes across sites are a knowledge gap that limits scaling or modeling efforts beyond averaging a limited number of field observations. The objective of this project is to investigate the role of marsh platform inundation frequency and flooding duration, as determined by elevation within the tidal frame, as a driver and predictor of lateral C and TA exports. This project will test the hypothesis that DOC, DIC and TA export increases with decreasing marsh platform elevation within the tidal frame due to: 1) increased porewater drainage and 2) a greater proportion of dissolved C flux versus CO2 evasion. A total of six New England marsh sites at unique elevations within the tidal frame will be evaluated during a one-month summer period, capturing peak C and TA exports modulated by spring-neap tidal variation and episodic events. Variability across each site will be constrained from local measurements of respiration rates and net ecosystem exchange, soil C content and accumulation rates, and local environmental conditions. This study will quantify lateral C and TA flux through tidal creeks from high-resolution, time-series surface water measurements using an in-situ dissolved inorganic carbon (DIC) sensor, biogeochemical and physical sensors. The depths of marsh drainage and DOC/DIC/TA export will be determined from sediment 224Ra:228Th disequilibria and will be compared with fluxes determined using the surface water approach. Overall, this project will provide a comprehensive framework for the evaluation of lateral DOC/DIC/TA exports from tidal wetlands and serve as a basis for the prediction of flux magnitude and variability into a future, warmer climate.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.

潮汐湿地从大气中清除了大量二氧化碳。该碳的某些部分被埋葬为土壤，通常称为“蓝色碳”。但是，通过湿地沉积物的潮汐冲洗，该碳的另一部分被出口到沿海海洋。从潮汐沼泽出口的碳量并不众所周知。该项目研究了使用最先进的方法从盐沼中控制碳出口的过程。这项研究的总体目标是开发碳出口的第一个预测模型。该模型将提供一种工具，以预测随着海平面上升的持续增长，沿海碳预算的未来变化。将外侧碳出口包含作为“蓝色碳”水槽将大大增加潮汐湿地碳汇的清单，并增加通过保护和恢复湿地来保存的生态系统服务套件。该项目将培训两名博士学位学生，并为多位本科生提供研究机会。研究人员将参加当地的外展活动，以提高人们对与该项目有关的科学的认识。侧面碳（C）出口在全球范围内超过C墓葬，北美东海岸的五倍高达5倍。但是，这些估计基于有限的数据。目前，控制横向C和跨站点的总碱度（TA）通量的机械驱动因素和环境变量是一个知识差距，它限制了缩放或建模工作，而不是平均有限的现场观测值。该项目的目的是研究沼泽平台基础设施频率和洪水持续时间的作用，这取决于潮汐框架内的升高，作为横向C和TA出口的驱动程序和预测指标。该项目将检验以下假设：DOC，DIC和TA导出会随着潮汐框架内的沼泽平台高度的降低而增加，这是由于：1）增加孔隙水排水以及2）溶解的C通量与CO2进化的比例更大。在一个月的夏季，将评估潮汐框架内部独特海拔的六个新英格兰沼泽地，捕获了由春季北极潮汐变化和情节事件调节的峰值C和TA出口。每个站点之间的可变性将受到呼吸率和净生态系统交换，土壤C含量和累积率以及当地环境条件的局部测量的限制。这项研究将通过使用原位溶解的无机碳（DIC）传感器，生物地球化学和物理传感器来定量通过高分辨率，时间序列地表水测量的潮汐小溪的侧向C和TA通量。沼泽排水和DOC/DIC/TA导出的深度将根据Sediment 224RA：228th then nodequilibria确定，并将与使用地表水方法确定的通量进行比较。总体而言，该项目将为评估潮汐湿地的外侧DOC/DIC/TA出口提供一个全面的框架，并作为对未来的通量幅度和可变性预测的基础，该奖项反映了NSF的法定任务，并认为通过该基金会的知识优点和广泛的criperia criperia criperia criperia criperia criptia criperia criptia the Priews take the奖项。