In Situ Experimentation to Determine the Impact of Sinking Particles on Dentrification and Anammox in Suboxic Waters

研究表明，颗粒有机物的再矿化与氮损失过程有关，即反硝化和厌氧氨氧化，它们共同代表了海洋氮循环中最大的不确定性。不幸的是，目前还没有直接证据表明下沉颗粒动力学与缺氧区氮循环有关。为了弥补这一疏忽，华盛顿大学的科学家们计划用一种新型的漂流陷阱孵化系统进行现场实验，该系统能够培养有和没有下沉颗粒的水，同时通过同位素配对实验测量有机物质再矿化，以确定氮循环。这种新型孵育器，加上改进的同位素标记方法，将首次在东热带北太平洋和南太平洋对这些过程进行实地速率测量。此外，研究人员计划进行代谢组学分析，以评估各种氮途径中使用的代谢重要化合物的浓度和周转，以及蛋白质组学评估与特定氮途径相关的酶的产生和丰度。就更广泛的影响而言，这项研究将导致开发一种新的研究工具，可以帮助我们进一步了解氮循环。科学家们将与华盛顿大学海洋科学教育卓越中心——海洋学习社区项目和促进奇卡诺人和印第安人科学项目协会合作，创建一个双语网站，旨在向美国、墨西哥和秘鲁的本科生解释这项研究。作为该项目的一部分，将支持和培训一名研究生和两名本科生。

Studies have suggested that remineralization of particulate organic matter is linked to nitrogen loss processes, namely denitrification and anammox, which together represent the largest uncertainties in the nitrogen cycle of the ocean. Unfortunately, no direct evidence has been gathered to relate sinking particle dynamics to nitrogen cycling in suboxic zones. To remedy this oversight, scientists from the University of Washington plan to carry out in-situ experiment with a novel drifting trap-incubation system capable of incubating water with and without sinking particles and simultaneously measure organic matter remineralization with isotopic pairing experiments to determine nitrogen cycling. The novel incubators, coupled with the enhanced isotopic labeling approach, will yield the first in situ rate measurements for these processes in the Eastern Tropical North and South Pacific. In addition, the researchers plan to do metabolomic profiling to evaluate the concentrations and turnover of metabolically important compounds used in the various nitrogen pathways, as well as proteomic evaluation of the production and abundance of enzymes pertinent to specific nitrogen pathways. In terms of the broader impacts, this study will lead to the development of a new research tool that can help further our knowledge of the nitrogen cycle. The scientists will work with the University of Washington's Centers for Ocean Sciences Education Excellence-Ocean Learning Communities Program and the Society for the Advancement of Chicanos and Native Americans in Science Program to create a dual-language website aimed at explaining the research to be carried out to undergraduates both in the United States, as well as Mexico and Peru. One graduate student and two undergraduate students would be supported and trained as part of this project.