OCE-PRF Effects of below-ground complexity on seagrass sediment structure and function

OCE-PRF 地下复杂性对海草沉积物结构和功能的影响

• 批准号: 2126708
• 负责人: Kara Gadeken
• 金额: $ 21.09万
• 依托单位: SUNY at Stony Brook
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-12-01 至 2024-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2126708&HistoricalAwards=false
• 关键词: OCE; PRF; Effects; below; ground

This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2).Marine sediments control the fate of carbon in the ocean by either metabolizing (“breaking down”) organic matter or burying it away. However, sediments are somewhat of a “black box”. Chemistry and ecology are closely connected in sediments, making it difficult to identify which processes control metabolism. This problem is even more pronounced in seagrass beds which are important coastal ecosystems and sites of very high carbon burial. Seagrass roots create complex structures that exchange nutrients and oxygen with the surrounding sediment, and burrowing animals can increase sediment metabolism by mixing and flushing water through sediments. This results in variability in seagrass sediment metabolism that is currently not well explained. The proposed research will link differences in seagrass root structure and animal communities to variation in sediment metabolism rates. The results of this research will inform strategies to manage and protect seagrass beds and anticipate changes in their valuable ecosystem services. Undergraduates from underrepresented groups will be involved in the research and mentored in their own research projects. The findings of the project will be adapted into a middle/high school level lesson plan on “Hidden Complexity” to teach students about the relationships between physical structure, chemistry and ecology in nature. The overarching goal of the proposed research is to integrate the complex physical structure and geochemical activity of seagrass roots and rhizomes into a model of the seagrass below-ground environment to assess which features of that environment affect sediment metabolism. Dense, complex root mats may oxygenate sediments more and drive higher sediment metabolism rates, and the 3D structure of the roots may control what fauna can live there and by extension the metabolism-enhancing activities the fauna perform. Specific goals of the project are to; (1) determine how the physical-chemical environment created by seagrass roots and rhizomes influences macrofaunal functional diversity, (2) assess how variation in the sediment physical-chemical environment at different locations in an expanding seagrass bed corresponds to variation in sediment metabolism, and (3) assess how differences in the sediment physical-chemical environment between seagrass taxa corresponds to variation in sediment metabolism. Physical structure will be characterized using CT imaging and geochemical patterns will be measured using planar optode imaging and targeted microprofiling. The structural and geochemical data will be integrated together using multiphysics modeling techniques to simulate geochemical permeance into the sediment around seagrass roots. These model results will then be compared to measurements of sediment metabolism from in situ benthic chambers to draw conclusions about the influence of roots on total sediment oxygenation and faunal behavior. The combination of non-destructive CT and planar optode imaging into a unified model will provide valuable information on the 3D structuring of seagrass sediments previously only described to a limited extent. The developed methodologies will also be of use to other researchers studying complexity in “opaque” systems, such as marshes, mangroves, and soils. By describing variation in below-ground structure, this work will provide a mechanistic understanding of its processes that can then be connected to larger-scale patterns in seagrass ecosystems, generating valuable knowledge for seagrass conservation, restoration, and management, and informing on seagrass susceptibility to climate change.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.

该奖项的全部或部分资金来自《2021年美国救援计划法案》(公法117-2)。海洋沉积物通过代谢(分解)有机物或将其掩埋来控制海洋中碳的命运。然而，沉积物在某种程度上是一个“黑匣子”。在沉积物中，化学和生态密切相关，因此很难确定哪些过程控制新陈代谢。这个问题在海草床上更加明显，海草床是重要的沿海生态系统，也是非常高碳埋藏的地点。海草根创造了复杂的结构，与周围的沉积物交换营养和氧气，穴居动物可以通过混合和冲洗沉积物中的水来增加沉积物的新陈代谢。这导致了海草沉积物代谢的变异性，目前还没有得到很好的解释。这项拟议的研究将把海草根结构和动物群落的差异与沉积物代谢率的变化联系起来。这项研究的结果将为管理和保护海草床的战略提供参考，并预测其宝贵的生态系统服务的变化。来自代表性不足群体的本科生将参与研究，并在自己的研究项目中得到指导。该项目的研究结果将被改编成初中/高中水平的《隐藏的复杂性》课程计划，向学生传授物理结构、化学和自然生态之间的关系。拟议研究的首要目标是将海草根和根茎的复杂物理结构和地球化学活动纳入海草地下环境模型，以评估该环境的哪些特征影响沉积物新陈代谢。密集、复杂的根垫可能会给沉积物带来更多氧气，并推动更高的沉积物代谢率，而根部的3D结构可能控制着哪些动物可以在那里生活，进而控制动物进行的新陈代谢促进活动。该项目的具体目标是：(1)确定海草根和根茎创造的物理化学环境如何影响大型动物功能多样性；(2)评估不断扩大的海草床不同位置的沉积物物理化学环境的变化如何与沉积物新陈代谢的变化相对应；(3)评估海草分类群之间的沉积物物理化学环境的差异如何与沉积物新陈代谢的变化相对应。物理结构将使用CT成像进行表征，地球化学模式将使用平面光电成像和定向显微剖面图进行测量。将使用多物理建模技术将结构和地球化学数据整合在一起，以模拟海草根部周围沉积物中的地球化学渗透。然后将这些模型结果与现场海底洞穴的沉积物新陈代谢测量结果进行比较，以得出关于根部对总沉积物氧合和动物行为的影响的结论。将无损CT和平面光电成像结合到一个统一的模型中，将为以前仅在有限程度上描述的海草沉积物的三维结构提供有价值的信息。开发的方法也将对其他研究“不透明”系统中的复杂性的研究人员有用，例如沼泽、红树林和土壤。通过描述地下结构的变化，这项工作将提供对其过程的机械理解，然后可以与海草生态系统中更大规模的模式相联系，为海草保护、恢复和管理产生宝贵的知识，并提供海草对气候变化的敏感性的信息。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。