Quantifying Acidification Mechanisms of Saharan Dust Aerosols in the Northeastern Subtropical Atlantic: Implications for Iron Solubility and Marine Primary Productivity

将研究东部副热带大西洋上空尘埃气溶胶的硫和氮酸化途径，以深入了解铁的溶解以及生物地球化学和气候反馈的这些过程。西班牙RODA号巡航期间，将在东北副热带大西洋收集不同大小的气溶胶和雨水，并分析硫酸盐和硝酸盐的主要离子浓度和同位素。将使用全球化学传输模式GEOS-CHEM对测量结果进行定量解释。对气溶胶和海洋样品中铁的形态和浮游植物丰度的协同测量为研究大气酸化对铁在尘埃气溶胶中的溶解度的作用及其对海洋初级生产力的潜在影响提供了机会。对尘埃大气酸化机制的制约将有助于理解海洋生物地球化学循环和相关的气候反馈。该项目将大气化学测量与海洋生物指标相结合，涉及来自美国和西班牙的团体，为促进国际合作提供了机会。更广泛的影响还包括在跨学科和国际背景下对一名研究生进行地球化学分析和化学运输建模方面的培训，以及对一名博士后研究员的支持。

Sulfur and nitrogen acidification pathways of dust aerosols over the eastern subtropical Atlantic will be studied to provide insight into these processes for iron solubility and biogeochemical and climate feedbacks. Size-segregated aerosols and rainwater will be collected during the Spanish RODA (English translation = Oceanic Eddies and Atmospheric Deposition in the Canary Current) cruise in the northeastern subtropical Atlantic Ocean, and major ion concentrations and isotopes of sulfate and nitrate will be analyzed. The global chemical transport model GEOS-CHEM will be used for quantitative interpretation of the measurements. Collaborative measurements of iron speciation in aerosol and ocean samples and phytoplankton abundance provide the opportunity to investigate the role of atmospheric acidification on the solubility of iron in dust aerosols and its potential effects on marine primary productivity. Constraints on atmospheric acidification mechanisms of dust will aid in understanding marine biogeochemical cycles and associated climate feedbacks. This project combines measurements of atmospheric chemistry with marine biological indicators involving groups from the U.S. and Spain, providing an opportunity to foster international collaboration. Broader impacts also include the training of one graduate student in geochemical analysis and chemical transport modeling in an interdisciplinary and international context, and support for a postdoctoral researcher.