MRI: Acquisition of a Nuclear Magnetic Resonance Spectrometer for Marine Biogeochemical Research

海洋生产力，我们星球的健康，以及我们现代社会的许多基础资源，在很大程度上是非常微小的单细胞微生物在海洋中制造和降解有机化合物的副产品。 海洋微生物每天合成大量的蛋白质、糖和脂肪。 在这样做的过程中，它们制造了我们呼吸的大部分氧气，它们从大气中去除有害的二氧化碳，并且它们是许多具有商业重要性的海洋鱼类和甲壳类动物的食物。 微生物“清洁”海水中的污染物，并作为海洋生态系统的基础。 然而，海洋微生物生活在一个竞争激烈的环境中。 微生物生长和茁壮成长所需的营养物质极其稀缺，而营养物质循环效率极高。 即使是微生物营养循环中的小干扰也会产生重大后果;海水中的氧气可能消失，生态系统可能崩溃。 为了了解微生物循环的运作方式，我们需要识别和跟踪维持微生物生命的关键有机化合物和营养物质。 在此，我们请求提供资金，用于对一台核磁共振光谱仪进行翻新和现代化改造，以便在一系列旨在了解微生物营养循环的海洋生物地球化学研究中使用。 该仪器将允许伍兹霍尔海洋研究所（WHOI）的一些科学家，学生和工作人员确定微生物用于从海水中提取营养物质的关键有机营养化合物，抵御捕食，并保护自己免受有害的紫外线辐射。 该仪器还将通过WHOI博士后和暑期学生奖学金计划以及WHOI/麻省理工学院海洋科学联合研究生计划培训下一代海洋科学家。铁和磷是两种限制和塑造大片海洋中海洋微生物群落的营养物质。 海洋铁和磷的化学形式在很大程度上是未知的，在接下来的几年里，我们建议使用NMR光谱来识别含铁，铜，钴和磷的有机化合物。 初步结果使我们能够表明，有机膦酸酯的降解是大气甲烷和乙烯的来源，而铁载体，海洋微生物合成的化合物，从环境中提取铁，在铁稀缺的海洋区域活跃地产生。 我们将通过美国的GEOTRACES计划继续这项工作，该计划将测量从阿拉斯加到塔希提岛的太平洋上的痕量金属和营养物质丰度。 许多有机化合物和有机营养物是由灰尘和河流排入海洋边缘提供的。 确定进入海洋的陆地有机物的化学特性及其对海洋微生物群落的可用性是了解微生物营养循环的关键。 我们在未来几年的第二个研究重点将是使用增强的核磁共振技术，以更好地表征陆地有机物质的性质和转化，因为它进入海洋。这个奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。

Ocean productivity, the health of our planet, and many of the resources foundational to our modern society, are in large part by-products by how very tiny, single celled microbes manufacture and degrade organic compounds in the ocean. Each day ocean microbes synthesize enormous quantities of proteins, sugars, and fats. In doing so, they manufacture a large share of the oxygen we breathe, they remove harmful carbon dioxide from the atmosphere, and they serve as food for many commercially important species of marine fish and crustaceans. Microbes "clean" seawater of pollutants, and serve as the base of marine ecosystems. However, marine microbes live a very competitive environment. The nutrients that microbes need to grow and thrive are extremely scarce, and nutrient cycling is extraordinarily efficient. Even small disturbances in microbial nutrient cycles can have major consequences; oxygen in seawater can disappear, and ecosystems can collapse. To understand how microbial cycles operate, we need to identify and track organic compounds and nutrients that are key to sustaining microbial life. Here we request funds to refurbish and modernize a nuclear magnetic resonance (NMR) spectrometer for use in a broad suite of marine biogeochemical studies designed to understand microbial nutrient cycles. The instrument will allow a number of scientists, students and staff at the Woods Hole Oceanographic Institution (WHOI) to identify key organic nutrient compounds that microbes use to extract nutrients from seawater, fend off predation, and shield themselves from harmful UV radiation. The instrument will also be critical to training the next generation of marine scientists through the WHOI postdoctoral and summer student fellowship programs, and the WHOI/MIT Joint Graduate Program in ocean sciences.Iron and phosphorus are two nutrients that limit and shape marine microbial communities across large tracts of the ocean. The chemical forms of marine iron and phosphorus are largely unknown, and over the next few years, we propose use the NMR spectroscopy to identify iron, copper, cobalt, and phosphorus containing organic compounds. Initial results have allowed us to show that the degradation of organic phosphonates is a source of atmospheric methane and ethylene, and that siderophores, compounds synthesized by marine microbes to extract iron from the environment, are actively produced in regions of the ocean where iron is scarce. We will continue this work through the US GEOTRACES program, which will measure trace metal and nutrient abundances across the Pacific Ocean from Alaska to Tahiti. Many organic compounds and organic nutrients are supplied by dust and river discharge into ocean margins. Determining the chemical identity of terrestrial organic matter entering the ocean, and its availability to marine microbial communities is key to understanding microbial nutrient cycles. A second focus of our research over the next few years will be in using enhanced NMR techniques to better characterize the nature and transformations of terrestrial organic matter as it enters the ocean.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.