The distribution of dissolved manganese (dMn) in the northeast Pacific across the Line-P transect was evaluated to investigate the mechanisms responsible for the spatial and temporal variability of dMn. A total of 299 filtered seawater samples (< 0.4 μm) collected in August at the five major stations each year from 2010 to 2013 were analyzed. Vertical profiles of dMn showed a clear distinction between onshore and offshore stations. Within the Summer Mixing layer (SML), we observed high dMn concentrations in all years driven by external sources, such as river water, coastal sediments or eolian dust, as well as photo-reduction. At the onshore stations, the absolute concentration of dMn at the surface was annually variable, depending on the strength of the Ekman transport. Within the subsurface layer, dMn decreased rapidly with depth down to 150 m due to particle scavenging. Within the Oxygen Minimum Zone (OMZ), near the continental margin, we observed elevated and annually variable dMn. The high dMn concentration is likely due to mixing of remobilized Mn from the continental margin, which varies year-to-year depending on the intensity of sedimentary Mn reduction process. At the offshore stations, dMn showed subsurface maxima, within the Winter Mixing Layer (WML) rather than surface maxima. We attribute this to the combined effect of biological drawdown of dMn in the surface during the spring and summer, where iron (Fe) is depleted in this High Nutrient and Low Chlorophyll (HNLC) region, and remnant dMn deeper in the WML, from earlier in the year. Using a simple one-dimensional advection and diffusion model, we identified that dMn found in North Pacific Intermediate Water (NPIW) at the western end of the transect can be advected as far as the outermost of the onshore stations in 2011 and 2013, while dMn in the central area of the transect is likely diluted by low dMn water from the south in 2010 and 2012. Within the OMZ, dMn showed elevated and annually variable concentrations, yet the enhancement of dMn of this study area was found to be less intense than in other regions. Lastly, an eddy found in 2010 enhanced dMn concentrations within the surface mixing layers.

评估了Line-P断面东北太平洋中溶解锰（dMn）的分布，以研究造成dMn时空变化的机理。从2010年至2013年，每年八月在五个主要站点收集的299份过滤后的海水样品（<0.4μm）均进行了分析。dMn的垂直剖面显示了陆上和海上站点之间的明显区别。在夏季混合层（SML）中，我们观察到所有年份都受到外部因素（例如河水，沿海沉积物或风积尘埃以及减光作用）的驱使，dMn浓度很高。在陆上站，地表dMn的绝对浓度每年变化，这取决于埃克曼运输的强度。在地下层中，dMn由于清除了颗粒，深度下降到150 m时迅速下降。在大陆边缘附近的氧气最小区域（OMZ）内，我们观察到了dMn的升高和年度变化。dMn的高浓度很可能是由于大陆边缘混运的Mn混合造成的，该数量逐年变化，这取决于沉积Mn还原过程的强度。在离岸站，dMn表现出在冬季混合层（WML）内的地下最大值，而不是表面最大值。我们将其归因于春季和夏季dMn在表面的生物学回落的综合作用，其中铁（Fe）在该高营养和低叶绿素（HNLC）区域被耗尽，而dMn在WML较深处从早期开始耗尽。在这一年。使用简单的一维对流扩散模型，我们发现，在该样带西端的北太平洋中间水（NPIW）中发现的dMn可以平移到2011年和2013年最远的陆上站，而该样带中部地区的dMn可能会被稀释。 2010年和2012年，南部的dMn水很低。在OMZ地区，dMn的浓度升高且每年变化，但发现该研究区dMn的增强强度不及其他地区。最后，2010年发现的涡流增强了表面混合层中dMn的浓度。dMn浓度升高且每年变化，但该研究区的dMn增强作用不如其他地区强。最后，2010年发现的涡流增强了表面混合层中dMn的浓度。dMn浓度升高且每年变化，但该研究区的dMn增强作用不如其他地区强。最后，2010年发现的涡流增强了表面混合层中dMn的浓度。