Dissolved iron concentration and the solubility inferred by humic-like fluorescent dissolved organic matter in the intermediate water in the North Pacific including the marginal seas
Dissolved iron concentration and the solubility inferred by humic-like fluorescent dissolved organic matter in the intermediate water in the North Pacific including the marginal seas
复制标题
北太平洋包括边缘海中间水体中的溶解铁浓度和类腐殖质荧光溶解有机物推断的溶解度
DOI：
10.1029/2022jg007159
复制
发表时间：
2023
影响因子：
3.7
通讯作者：
and J. Nishioka
中科院分区：
文献类型：
--
作者：
Yamashita;Y.;and J. Nishioka
人们发现边缘海是北太平洋通过中间水循环溶解铁（Fe）的重要外部来源。在这里，我们展示了从北太平洋（包括边缘海、鄂霍次克海和白令海）类腐殖质荧光溶解有机物（FDOMH）推断出的溶解铁浓度和 Fe(III) 溶解度的综合空间分布。 FDOMH 被用作中层和深水中溶解铁的化学形态的代表，其中先前观察到 FDOMH 和 Fe(III) 溶解度之间存在线性关系。当溶解的 Fe 浓度超过 Fe(III) 溶解度时，假设 Fe(III) 溶解度等于 FDOMH-Fe 络合物的浓度，超过 Fe(III) 溶解度的过量溶解 Fe 浓度假设为未与 FDOMH 络合的胶体 Fe。在中间水体中，溶解的Fe浓度超过了边缘海的Fe(III)溶解度，而中间水循环的下游明显存在过量的Fe(III)溶解度，这表明边缘海陆架和斜坡沉积物中溶解的Fe的主要化学形态从胶体Fe转变为FDOMH-Fe复合物。根据之前的研究结果，即鄂霍次克海和白令海中间水中的总铁中不稳定颗粒铁占主导地位，我们假设沉积物来源的铁的平均尺寸在中间水的运输过程中减小，很可能是由于可逆清除，其中不稳定颗粒铁的去除率最高，FDOMH-Fe复合物的去除率最低。
The marginal seas have been found to be important external sources of dissolved iron (Fe) in the North Pacific through circulation of intermediate water. Here, we show comprehensive spatial distributions of dissolved Fe concentrations and Fe(III) solubilities inferred from humic‐like fluorescent dissolved organic matter (FDOMH) over the North Pacific, including the marginal seas, the Sea of Okhotsk, and the Bering Sea. FDOMHwas used as a proxy of chemical speciation of dissolved Fe in the intermediate and deep waters where liner relationships were previously observed between FDOMHand Fe(III) solubility. When dissolved Fe concentration exceeds Fe(III) solubility, Fe(III) solubility is assumed to be equivalent to concentration of FDOMH‐Fe complexes, and excess dissolved Fe concentration above the Fe(III) solubility is assumed to be colloidal Fe which is not complexed with FDOMH. In the intermediate water, the dissolved Fe concentration exceeded the Fe(III) solubility in the marginal seas, while excess Fe(III) solubility was evident downstream of the intermediate water circulation, suggesting that the major dissolved Fe chemical form derived from shelf and slope sediments in the marginal seas changed from colloidal Fe to FDOMH‐Fe complexes. With the previous findings, namely the dominance of labile particulate Fe in total Fe in the intermediate water of the Sea of Okhotsk and the Bering Sea, we hypothesized that the average size of sediment‐derived Fe decreases during transportation by intermediate water, most likely due to reversible scavenging with the highest removal rate for labile particulate Fe and the lowest removal rate for FDOMH‐Fe complexes.