MCA: Characterizing Rhizosphere Decomposition with Novel Techniques in Contrasting Salt Marshes

MCA：用对比盐沼中的新技术表征根际分解

• 批准号: 2121019
• 负责人: Amanda Spivak
• 金额: $ 37.03万
• 依托单位: University of Georgia Research Foundation Inc
• 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 2024-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2121019&HistoricalAwards=false
• 关键词: MCA; Characterizing; Rhizosphere; Decomposition; Novel

Salt marshes provide several important ecosystem services to coastal communities. One of the most valuable services is buffering coasts from damage due to rising sea levels and coastal storms. Marshes provide this service by building soils and growing vertically. Marsh soils are mostly made of minerals delivered by rivers and organic matter from marsh grasses. Delivery of these materials can be put at risk by human activities. This places additional importance on efficient burial and long-term preservation of organic matter in maintaining marsh elevation. This research examines the small-scale mechanisms controlling soil organic matter preservation. Laboratory and field experiments are testing how three preservation mechanisms operate under controlled and natural conditions. Results help explain spatial variability in soil carbon stocks and may inform models predicting salt marsh survival with sea-level rise. The expertise gained through this project provides both career development and advances in coastal carbon science. High school students and undergraduate students are also gaining exposure to this science project through an outreach program in Georgia. Three mechanisms affecting decomposition — oxygen availability, mineral protection, and root exudate priming — are being investigated using novel geochemical and isotope tracing and imaging techniques. The experiments are based at two Long-Term Ecological Research sites – Georgia Coastal Ecosystems and Plum Island Ecosystems – which have similar tidal ranges, marsh grasses, and production rates but different carbon storage rates. In the lab, mineral and organic rhizosphere soils are maintained under oxic or anoxic conditions to test how soil carbon is preserved. A field experiment is being deployed at both sites, to manipulate tidally-driven redox conditions. The research is adding knowledge about how redox conditions affect carbon transformations. The fate of root exudates through microbial incorporation or soil particle stabilization helps discover what makes both mineral and organic salt marshes resilient to changing coastal conditions.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.

盐沼为沿海社区提供了几种重要的生态系统服务。其中最有价值的服务之一是缓冲因海平面上升和沿海风暴造成的海岸破坏。沼泽通过建造土壤和垂直生长来提供这种服务。沼泽土壤主要由河流输送的矿物质和沼泽草中的有机物组成。这些材料的运输可能会受到人类活动的威胁。这使得有效掩埋和长期保存有机物质在保持沼泽高程方面更加重要。本研究探讨了控制土壤有机质保存的小尺度机制。实验室和实地试验正在测试三种保存机制在受控和自然条件下的运作情况。研究结果有助于解释土壤碳储量的空间变异性，并可能为预测海平面上升时盐沼生存的模型提供信息。通过该项目获得的专业知识为沿海碳科学提供了职业发展和进步。高中生和本科生也通过乔治亚州的外展项目接触到这个科学项目。利用新的地球化学和同位素示踪和成像技术，正在研究影响分解的三个机制-氧气有效性、矿物保护和根渗出物启动。这些实验是在两个长期生态研究地点进行的——乔治亚海岸生态系统和梅岛生态系统——这两个地点有相似的潮汐范围、沼泽草和产量，但碳储存率不同。在实验室里，矿物质和有机根际土壤被维持在有氧或无氧条件下，以测试土壤碳是如何保存的。目前正在两个地点进行现场实验，以控制潮汐驱动的氧化还原条件。这项研究增加了关于氧化还原条件如何影响碳转化的知识。通过微生物结合或土壤颗粒稳定，根渗出物的命运有助于发现是什么使矿物和有机盐沼能够适应不断变化的海岸条件。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识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

Peat Decomposition and Erosion Contribute to Pond Deepening in a Temperate Salt Marsh

泥炭分解和侵蚀导致温带盐沼池塘加深

• DOI: 10.1029/2022jg007063
• 发表时间: 2023
• 期刊: Journal of Geophysical Research: Biogeosciences
• 作者: Luk, Sheron;Eagle, Meagan J.;Mariotti, Giulio;Gosselin, Kelsey;Sanderman, Jonathan;Spivak, Amanda C.
• 通讯作者: Spivak, Amanda C.

Ephemeral microbial responses to pulses of bioavailable carbon in oxic and anoxic salt marsh soils

• DOI: 10.1016/j.soilbio.2023.109157
• 发表时间: 2023-08
• 期刊: Soil Biology and Biochemistry
• 影响因子: 9.7
• 作者: A. Spivak;A. Pinsonneault;C. Hintz;J. Brandes;J. Megonigal