Stoichiometry of Oceanic Remineralization by Non-Linear Global Optimization on an Improved Data Set

基于改进数据集的非线性全局优化的海洋再矿化化学计量

• 批准号: 0727170
• 负责人: Jorge Sarmiento
• 金额: $ 43.46万
• 依托单位: Princeton University
• 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=0727170&HistoricalAwards=false
• 关键词: Stoichiometry; Oceanic; Remineralization; Non; Linear

Remineralization ratios represent the average stoichiometric relationships of elements released by decomposition of sinking particles as they fall thought the water column to the ocean floor. In theory, these ratios are similar, on appropriate temporal and spatial scales, to the ratios in which elements are taken up by phytoplankton. These ratios are often used in biogeochemical modeling and they permit linking the different cycles through simple proportionality. Although variations in the ratio in space or time can have large-scale oceanic impact, current consensus suggests that remineralization ratios are relatively constant in the deep ocean, but that significant variations exist in the more dynamic upper layers. If one is to correctly predict the impacts of iron fertilization, to measure the efficiency of the organic carbon pump, or to investigate the effects of climate change on oceanic biogeochemical cycles, and so make claims about the significance of these processes on anthropogenically relevant scales (decades), an accurate global depiction of organic matter remineralization is required. Researchers from Princeton University propose to carry out a global investigation of the pattern of water column remineralization of carbon, alkalinity, oxygen and the major nutrients (nitrate, phosphate, silicate) using a newly developed mathematical estimation scheme and the Global Ocean Data Analysis Project (GLODAP) data set. Using a newly developed method to solve a coupled system of equation describing mixing of multiple water masses and remineralization of particulate matter into dissolved nutrients, they can simultaneously solve for the water mass fractions and each remineralization ratio, without assuming ratio constancy, and propagate uncertainties in water mass characterization using a geographic Monte-Carlo approach. The broader impacts of this research will include providing the oceanographic community with a global database containing 1) the fractions of the major water masses constituting most water sample collected as part of the major oceanographic expeditions of the last few decades, 2) the remineralization ratios inferred from the dissolved nutrient fields, and 3) the faction of the measured concentrations that arises from biological respiration or dissolution. No centralized data repository containing this information currently exists, and existing methods used to compute these parameters are limited. In addition, a graduate student would be trained.

再矿化率表示下沉颗粒通过水柱落到海底时分解释放的元素的平均化学计量关系。从理论上讲，在适当的时间和空间尺度上，这些比率与浮游植物吸收元素的比率相似。这些比率经常用于地球化学建模，它们允许通过简单的比例将不同的循环联系起来。 尽管空间或时间比例的变化可能会对海洋产生大规模的影响，但目前的共识表明，深海中的再矿化率相对恒定，但在更具动态的上层存在显着变化。如果要正确预测铁施肥的影响，测量有机碳泵的效率，或调查气候变化对海洋生物地球化学循环的影响，并因此声称这些过程在生物学相关尺度（数十年）上的重要性，则需要准确描述有机物的全球化。 普林斯顿大学的研究人员提议，利用新开发的数学估算方案和全球海洋数据分析项目数据集，对碳、碱度、氧和主要营养物质（硝酸盐、磷酸盐、硅酸盐）的水柱矿化模式进行全球调查。使用一种新开发的方法来解决一个耦合系统的方程描述混合的多个水团和颗粒物的溶解营养素，他们可以同时解决水的质量分数和每个矿化比，而不假设比例恒定性，并传播不确定性水团表征使用地理蒙特-卡罗方法。这项研究的更广泛的影响将包括为海洋学界提供一个全球数据库，其中包括：1）构成过去几十年主要海洋学考察一部分收集的大多数水样的主要水团的分数，2）从溶解营养盐场推断的矿化率，和3）由生物呼吸或溶解产生的测量浓度的部分。目前不存在包含此信息的集中式数据存储库，并且用于计算这些参数的现有方法有限。此外，还将培训一名研究生。