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运输将物质从大陆转移到海洋。迄今为止，这些重要的陆海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个别要素进行了研究。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模型与全球海洋生物地球化学模型结合起来。他们将模拟海洋中营养物质硅酸盐、硝酸盐、铵、磷酸盐、铁和地壳示踪剂铝在大气中的沉积和溶解。这些关键营养物质调节着海洋浮游植物的生长速度、群落结构和初级生产，因此与碳循环和海气二氧化碳交换密切相关。海洋模式包括关键的浮游植物官能团和C、O、N、P、Si和Fe的生物地球化学循环的明确处理。自然和人为气溶胶的矿物学将因来源地区和粒径而异，沉积时的营养物溶解度将取决于气溶胶的非均质化学、化学风化和运输过程中的老化，以及沉积是湿的还是干的。科学家们将制作并传播这些营养物质沉积到海洋的全球地图。此外，他们还将在区域到全球尺度上估算每种营养物对浮游植物群落结构、营养物限制的时空格局、地表水碳输出和海气CO2通量的影响。他们的研究将是第一批在全球范围内估计海洋对这些模式的敏感性，并在一个耦合的地球系统模型框架中量化它们在推动海洋碳循环中的作用的研究。就更广泛的影响而言，更好地了解Si、Fe、N、P和C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运作的理解，并增强我们在不同排放和养分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关心（来自大气来源的）营养负荷对水质的影响的广泛的公共和私营实体，以及对二次生产、渔业和海洋资源管理以及海洋生态系统动力学感兴趣的实体将是有价值的。除了科学价值外，两名研究生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.