Global Atmospheric Nutrient Deposition and Ocean Biogeochemistry

硅、氮、磷和铁的生物地球化学循环涉及通过自然和人为气溶胶的大气传输将物质从大陆转移到海洋。迄今为止，这些重要的陆地-海洋联系及其对海洋生态系统和生物地球化学循环的影响仅针对单个元素进行了研究。在这项研究中，来自加州大学欧文分校的研究人员将把大气化学和气溶胶输送的模型与全球海洋生物地球化学模型结合起来。他们将模拟大气中营养物质硅酸盐、硝酸盐、铵、磷和铁以及地壳示踪剂铝在海洋中的沉积和溶解。这些关键营养物质调节着海洋中浮游植物的生长速度、群落结构和初级生产力，因此与碳循环和海气二氧化碳交换密切相关。海洋模型包括关键的浮游植物功能群和对C、O、N、P、Si和Fe的生物地球化学循环的显式处理。天然和人为气溶胶的矿物学将随来源区域和颗粒大小而变化，沉积时的营养物质溶解度将取决于气溶胶的非均质化学、运输过程中的化学风化和老化以及沉积是湿的还是干的。科学家们将制作并发布每一种营养物质向海洋沉积的全球地图。此外，他们还将评估每种营养物质对浮游植物群落结构、营养物质限制的时空模式、表层水域的碳输出以及区域到全球尺度的大气-海洋二氧化碳通量的影响。他们的研究将率先在全球范围内估计海洋对这些模式的敏感性，并在耦合地球系统模式框架中量化它们在推动海洋碳循环方面的作用。在更广泛的影响方面，更好地了解硅、铁、氮、磷和碳的生物地球化学循环之间的联系将提高我们对当今地球系统如何工作的理解，并增强我们在不同排放和营养负荷情景下预测未来气候变化的能力。所开发的模型工具和结果对于对营养物质负荷(来自大气来源)对水质的影响感兴趣的各种公共和私人实体以及对初级生产、渔业和海洋资源管理以及海洋生态系统动态感兴趣的实体将是有价值的。除了科学上的优点，两名研究生还将接受最新建模技术的培训。

ABSTRACTOCE-0452972The biogeochemical cycles of silicon, nitrogen, phosphorus, and iron involve substantial transfer of materials from the continents to the oceans through atmospheric transport of natural and anthropogenic aerosols. To date, these important land-ocean links and their influence on ocean ecosystems and biogeochemical cycling have only been studied for individual elements. In this study, investigators from the University of California at Irvine will couple models of atmospheric chemistry and aerosol transport to a global ocean biogeochemical model. They will simulate the atmospheric deposition and dissolution in the oceans of the nutrients silicate, nitrate, ammonium, phosphate, and iron, and the crustal tracer aluminum. These key nutrients regulate phytoplankton growth rates, community structure, and primary production in the oceans and hence are intimately linked with carbon cycling and air-sea CO2 exchange. The ocean model includes key phytoplankton functional groups and explicit treatment of the biogeochemical cycling of C, O, N, P, Si, and Fe. Mineralogy of both natural and anthropogenic aerosols will vary by source region and particle size, and the nutrient solubility upon deposition will vary dependent on aerosol heterogeneous chemistry, chemical weathering and aging during transport, and whether the deposition is wet or dry. The scientists will produce and disseminate global maps of deposition to the oceans for each of these nutrients. In addition, they will estimate the impact of each nutrient on phytoplankton community structure, spatio-temporal patterns of nutrient limitation, carbon export from surface waters, and air-sea CO2 flux at regional to global scales. Their studies will be among the first to estimate the ocean sensitivity to these patterns globally and to quantify their roles in driving the ocean carbon cycle in a coupled Earth System model framework. In terms of broader impacts, a better understanding of the links between the biogeochemical cycling of Si, Fe, N, P, and C will improve our understanding of how the Earth system works today and enhance our ability to predict future climate change under different emission and nutrient loading scenarios. The model tools developed and the results will be valuable to a wide array of public and private entities interested in the effects of nutrient loading (from atmospheric sources) on water quality, and for those interested in secondary production, fisheries and marine resource management, and ocean ecosystem dynamics. In addition to the scientific merit, two graduate students will be trained in the latest modeling techniques.