Collaborative proposal: Coupled biological and photochemical degradation of dissolved organic carbon in the Arctic

合作提案：北极溶解有机碳的生物和光化学耦合降解

• 批准号: 1754835
• 负责人: Byron Crump
• 金额: $ 49.52万
• 依托单位: Oregon State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-07-01 至 2025-06-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1754835&HistoricalAwards=false
• 关键词: Collaborative; proposal; Coupled; biological; photochemical

About half of the carbon that moves from land to streams, rivers, and lakes is lost to the atmosphere as carbon dioxide. Carbon from land is converted to CO2 mainly by microbial respiration and exposure to sunlight. Both processes happen in sunlit surface waters, but little is known about how they interact to produce CO2. For instance, previous research has shown that sunlight exposure can either increase or decrease microbial respiration. In addition, there is little known about how composition of microbial communities may influence microbial respiration. Understanding how microbes and sunlight interact is particularly important in the Arctic where thawing permafrost soils will release large amounts of carbon from land to water. Advancing our understanding of loss of this carbon to the atmosphere is critical to understanding the global carbon cycle. This project takes advantage of recent advances in microbial genomics and carbon chemistry to improve understanding of carbon cycling in Arctic freshwaters. This research will also engage high school teachers and students in scientific discovery and application. The PIs also plan to provide undergraduates with research opportunities through this project.Determining the controls on coupled photo-bio conversion of dissolved organic carbon (DOC) to CO2 is essential for understanding the drivers of CO2 fluxes to the atmosphere from inland waters in the Arctic. To gain this understanding, this project will use experiments to answer three questions: (Q1) How is microbial metabolism controlled by DOC chemistry? This question will be answered with incubations of microbial communities with DOC leached from surface soils and deeper permafrost soils from two dominant arctic landscapes. Microbial pathways of DOC conversion to CO2 will be identified by measuring microbial gene abundance and the expression of those genes, and molecular formulas of DOC that are consumed and produced during incubations identified by mass spectrometry; (Q2) How does DOC exposure to sunlight alter how microbes convert DOC to CO2? This question will be answered by exposing leached soil DOC to sunlight; (Q3) How does the longer-term adaptation of microbial communities affect the rate of DOC conversion to CO2? This question will be answered by measuring microbial abundance, respiration, production, and community composition (species) during the incubations. A detailed understanding of these processes is critical because conversion of permafrost soil carbon to CO2 has the potential to create a positive and accelerating feedback to atmospheric CO2 levels and resulting environmental changes.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.

从陆地转移到溪流、河流和湖泊的碳大约有一半以二氧化碳的形式消失在大气中。陆地上的碳主要通过微生物呼吸和阳光照射转化为二氧化碳。这两个过程都发生在阳光照射的地表水中，但人们对它们如何相互作用产生二氧化碳知之甚少。 例如，之前的研究表明，阳光照射可以增加或减少微生物呼吸。此外，人们对微生物群落的组成如何影响微生物呼吸知之甚少。 了解微生物和阳光如何相互作用在北极尤为重要，那里融化的永久冻土会将大量碳从陆地释放到水中。加深我们对碳流失到大气中的认识对于了解全球碳循环至关重要。 该项目利用微生物基因组学和碳化学的最新进展来增进对北极淡水碳循环的了解。这项研究还将吸引高中教师和学生参与科学发现和应用。 PI 还计划通过该项目为本科生提供研究机会。确定溶解有机碳 (DOC) 耦合光生物转化为 CO2 的控制对于了解 CO2 通量从北极内陆水域进入大气的驱动因素至关重要。为了获得这种理解，该项目将通过实验来回答三个问题：（Q1）DOC化学如何控制微生物代谢？ 这个问题将通过用从两个主要北极景观的表层土壤和更深的永久冻土中浸出的 DOC 培养微生物群落来回答。 通过测量微生物基因丰度和这些基因的表达，以及通过质谱法确定的孵化过程中消耗和产生的 DOC 的分子式，将确定 DOC 转化为 CO2 的微生物途径； (Q2) DOC 暴露在阳光下如何改变微生物将 DOC 转化为 CO2 的方式？ 通过将浸出的土壤 DOC 暴露在阳光下可以回答这个问题； (Q3) 微生物群落的长期适应如何影响 DOC 转化为 CO2 的速率？ 这个问题将通过测量孵化期间的微生物丰度、呼吸、生产和群落组成（物种）来回答。详细了解这些过程至关重要，因为永久冻土碳转化为二氧化碳有可能对大气二氧化碳水平和由此产生的环境变化产生积极且加速的反馈。该奖项反映了 NSF 的法定使命，并被认为值得通过评估获得支持利用基金会的智力优势和更广泛的影响审查标准。

项目成果

Preferential utilization of inorganic polyphosphate over other bioavailable phosphorus sources by the model diatoms Thalassiosira spp.

模型硅藻 Thalassiosira spp 优先利用无机多磷酸盐而不是其他生物可利用的磷源。

• DOI: 10.1111/1462
• 发表时间: 2019
• 期刊: Environmental Microbiology
• 影响因子: 5.1
• 作者: Diaz, Julia M.;Steffen, Rachel;Sanders, James G.;Tang, Yuanzhi;Duhamel, Solange
• 通讯作者: Duhamel, Solange

The Controls of Iron and Oxygen on Hydroxyl Radical (•OH) Production in Soils

铁和氧对土壤中羟自由基 (ⅢOH) 产生的控制

• DOI: 10.3390/soilsystems3010001
• 发表时间: 2019
• 期刊: Soil Systems
• 影响因子: 3.5
• 作者: Trusiak, Adrianna;Treibergs, Lija;Kling, George;Cory, Rose
• 通讯作者: Cory, Rose