Impact of Suboxia on Sinking Particles: Non-Redfield Diagenesis and its Potential Role in C fluxes and N Cycling

Suboxia 对沉降颗粒的影响：非红场成岩作用及其在碳通量和氮循环中的潜在作用

• 批准号: 0726522
• 负责人: Richard Keil
• 金额: $ 29.73万
• 依托单位: University of Washington
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-09-01 至 2011-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0726522&HistoricalAwards=false
• 关键词: Impact; Suboxia; Sinking; Particles; Non

The diagenesis of sinking particulate organic matter in suboxic water columns may be less efficient compared with the degradation rate that is observed in oxic water columns throughout the world's ocean. An alternative to differential degradation due to low oxygen concentration is that significant dust inputs in these same regimes might lead to enhanced organic carbon:mineral (ballast) fluxes. To test these ideas, a researcher from the University of Washington will participate in a cruise to the Arabian Sea aboard the R/V Revelle. To study whether degradation is less efficient, settling particles will be collected using drifting net traps and a series of ship-board experiments will be performed. Settling material will be incubated under oxic and suboxic conditions and the degradation rates and residual organic matter compositions of bulk settling material and specific organic components (proteins) will be measured. To evaluate the role of mineral ballast in generating enhanced fluxes, two approaches will be used; a) dust will be added to some trap incubations to probe whether adding mineral results in decreased organic matter diagenesis and thus enhanced carbon:mass ratios at the end of incubations, and b) trap and incubation samples will be probed for ballast types, mineral surface areas, and organic:mineral interactions using a combination of density fractionation, X-ray photoelectron spectroscopy, mineralogical and organic analyses.After the Arabian Sea cruise, the PI will visit the oxic, suboxic and anoxic basins of Nootka Sound, British Columbia to conduct a series of comparative experiments to the Arabian Sea. Nootka Sound is an ideal locale to compare with the Arabian Sea because unlike the Arabian Sea, Nootka Sound has inlets with deep water of varying redox conditions, making natural controlled experiments feasible. In addition to the broader impact arising from training a graduate student, this proposal will leverage an undergraduate mentoring program, the Apprenticeship Learning Program, where undergraduate researchers are mentored by two faculty members and receive multidisciplinary research training.

与在全世界海洋含氧水柱中观察到的降解速率相比，低氧水柱中下沉颗粒有机物的成岩作用可能效率较低。 由于低氧浓度导致的差异降解的另一种选择是，在这些相同的情况下大量的灰尘输入可能会导致有机碳：矿物（压载物）通量的增加。为了验证这些想法，华盛顿大学的一名研究人员将乘坐 R/V Revelle 号参加阿拉伯海巡航。 为了研究降解效率是否较低，将使用流网陷阱收集沉降颗粒，并进行一系列船上实验。沉降材料将在有氧和低氧条件下孵育，并测量散装沉降材料和特定有机成分（蛋白质）的降解率和残留有机物成分。 为了评估矿物压载物在产生增强通量方面的作用，将使用两种方法； a) 将在一些捕集器孵化中添加灰尘，以探讨添加矿物是否会导致有机质成岩作用减少，从而在孵化结束时提高碳质量比，b) 将结合密度分馏、X 射线光电子能谱、矿物学和有机分析，探测捕集器和孵化样品的压载物类型、矿物表面积以及有机物：矿物相互作用。 此次阿拉伯海巡航，PI将参观不列颠哥伦比亚省努特卡海峡的好氧、低氧和缺氧盆地，对阿拉伯海进行一系列对比实验。努特卡海峡是与阿拉伯海进行比较的理想地点，因为与阿拉伯海不同，努特卡海峡拥有不同氧化还原条件的深水入口，使得自然控制实验成为可能。除了培训研究生产生更广泛的影响外，该提案还将利用本科生指导计划，即学徒学习计划，本科生研究人员将由两名教员指导并接受多学科研究培训。