Earth and Ocean Science, National Oceanography Centre Southampton, University of Southampton, Southampton, SO14 3ZH, UK.
GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, 24148, Germany.
Sci Rep. 2018 Jan 19;8(1):1283. doi: 10.1038/s41598-018-19472-1.
Iron (Fe) is an essential micronutrient for marine microbial organisms, and low supply controls productivity in large parts of the world's ocean. The high latitude North Atlantic is seasonally Fe limited, but Fe distributions and source strengths are poorly constrained. Surface ocean dissolved Fe (DFe) concentrations were low in the study region (<0.1 nM) in summer 2010, with significant perturbations during spring 2010 in the Iceland Basin as a result of an eruption of the Eyjafjallajökull volcano (up to 2.5 nM DFe near Iceland) with biogeochemical consequences. Deep water concentrations in the vicinity of the Reykjanes Ridge system were influenced by pronounced sediment resuspension, with indications for additional inputs by hydrothermal vents, with subsequent lateral transport of Fe and manganese plumes of up to 250-300 km. Particulate Fe formed the dominant pool, as evidenced by 4-17 fold higher total dissolvable Fe compared with DFe concentrations, and a dynamic exchange between the fractions appeared to buffer deep water DFe. Here we show that Fe supply associated with deep winter mixing (up to 103 nmol m d) was at least ca. 4-10 times higher than atmospheric deposition, diffusive fluxes at the base of the summer mixed layer, and horizontal surface ocean fluxes.
铁（Fe）是海洋微生物的必需微量元素，在世界海洋的大部分地区，低铁供应控制着生产力。北大西洋高纬度地区季节性缺铁，但铁的分布和源强度受到很大限制。2010 年夏季，研究区域的表层海洋溶解铁（DFe）浓度较低（<0.1 nM），2010 年春季，由于艾雅法拉火山（Eyjafjallajökull）爆发，冰岛海域的 DFe 浓度高达 2.5 nM，对生物地球化学产生了重大影响。雷克雅内斯脊系统附近的深水浓度受到明显沉积物再悬浮的影响，并表明存在额外的热液喷口输入，随后铁和锰羽流的侧向输送长达 250-300 公里。颗粒态铁是主要的铁库，这一点可以从总可溶解铁（4-17 倍高于 DFe 浓度）与 DFe 浓度之间的关系中得到证明，各分数之间的动态交换似乎缓冲了深水 DFe。本研究表明，与深冬混合（高达 103 nmol m d）相关的铁供应至少是大气沉降、夏季混合层底部的扩散通量和表层海洋水平通量的 4-10 倍。
