Fate of Phosphorus during Photochemical Cycling of Iron Oxyhydr(oxides) in the Upper Ocean

陆地来源的尘埃是海洋营养枯竭地区微量营养素铁(Fe)的重要来源。来自风沙输入的铁主要以氢氧化铁的形式存在，由于它对磷(P)有很强的亲和力，因此有相当数量的这种营养与之相关。这些营养物质加在一起会影响初级生产。一旦将粉尘引入阳光照射的地表水域，氢氧化铁颗粒就会发生光还原溶解，从而增强生物可利用铁，但这一过程对相关磷的影响尚不清楚。夏威夷大学的研究人员计划利用合成的氢氧化铁和天然粉尘样本进行一系列实验室实验，以确定这些颗粒物一旦被光化学还原，与其相关的磷的命运。这项研究的结果将确定富铁粉尘是现有生物可利用磷库的来源，还是由于海洋环境中氢氧化铁的重复光化学溶解/再沉淀循环而通过吸附清除而清除的汇。更广泛的影响：除了对磷循环提供新的见解外，这项研究还将支持和培训一名夏威夷血统的研究生。

Terrestrially-derived dust is an important source of the micronutrient iron (Fe) to nutrient-depleted regions of the oceans. The Fe from aeolian inputs is predominantly in the form of ferric oxyhydroxide which because of its strong affinity for phosphorus (P) have significant amounts of this nutrient associated with it. Together these nutrients can impact primary production. Once dust is introduced to sunlit surface waters, the ferric oxyhydroxide particles are subject to photoreductive dissolution which enhances bioavailable Fe but the impact of this process on the associated P is unknown. Researchers at the University of Hawaii plan to carry out a series of laboratory experiments using synthetic ferric oxyhydroxides and natural dust samples to determine the fate of P associated with these particles once they are photochemically reduced. Results from this study will establish whether Fe-rich dust is a source to the existing bioavailable pool of P or a sink due to removal via sorptive scavenging as a consequence of repetitive photochemical dissolution/re-precipitation cycles of ferric oxyhydroxides in the marine environment. Broader Impacts: Besides providing new insights on the phosphorus cycle, this research would support and train one graduate student of Hawaiian descent.