Complexation by dissolved organic ligands affects the bioavailability and distribution of copper and other bioactive trace metals in seawater. However, relatively little is known about the origin and identity of marine copper-complexing ligands, particularly in Arctic waters. We used immobilized copper(II)-ion affinity chromatography (IMAC) to isolate dissolved (< 0.2 μm) copper ligands from seawater samples collected during the 2015 Canadian Arctic GEOTRACES expedition. UV detection at 254 nm was employed to monitor elution of the compounds retained by IMAC. The areas of the resulting peaks were used to generate depth profiles that show, for the first time, how copper ligands are distributed across the Canadian Arctic. Copper ligand concentrations ranged from 0.9 to 4.8 nM, the depth of highest ligand concentration often coinciding with the chlorophyll maximum depth. Correlations between ligand concentration and in situ chlorophyll-a fluorescence suggest that marine phytoplankton or cyanobacteria could be an important source of copper ligands. A correlation was also observed between copper ligand and dissolved copper concentrations in Baffin Bay. Comparison of these results with published data for humic substances and other dissolved organic matter suggests that terrestrial input contributes to the pool of ligands captured by IMAC, particularly in the Canada Basin and Canadian Arctic Archipelago.

溶解的有机配体的络合作用会影响铜和其他生物活性痕量金属在海水中的生物利用度和分布。但是，关于海洋铜络合配体的起源和种类知之甚少，尤其是在北极水域。我们使用固定化铜离子（II）-离子亲和色谱（IMAC）从2015年加拿大北极GEOTRACES探险队收集的海水样品中分离出溶解的（<0.2μm）铜配体。254 nm处的UV检测用于监测IMAC保留的化合物的洗脱。所得峰的面积用于生成深度剖面，这首次显示了铜配体如何在加拿大北极地区分布。铜配体浓度范围为0.9到4.8 nM，最高配体浓度的深度通常与叶绿素的最大深度一致。配体浓度与原位叶绿素-a荧光表明海洋浮游植物或蓝细菌可能是铜配体的重要来源。还观察到铜配体与巴芬湾中溶解的铜浓度之间存在相关性。将这些结果与腐殖质和其他溶解有机物的公开数据进行比较表明，地面输入有助于IMAC捕获的配体库，特别是在加拿大盆地和加拿大北极群岛。