Abstract Wet and dry depositions in the southern East China Sea (ECS) differ substantially in their relative proportion of high-molecular-weight organic nitrogen (HMW-ON) and low-molecular-weight organic nitrogen (LMW-ON). By distinguishing between ON with different molecular weights, this study proposes an improved calculation of the contributions of dry and wet depositions to the new production in surface seawater in the southern ECS. This study used 54 rainwater samples and 12 sets of size-fractionated atmospheric particles from the southern ECS, collected from January to December 2014. Dissolved or water-soluble samples were subjected to an ultrafiltration method to separate ON into HMW-ON and LMW-ON. The overall average concentration of ON was 56.5 ± 18.8 μM in wet deposition and 117.0 nmol m−3 in dry deposition. LMW-ON and HMW-ON constituted 82 ± 9% and 18 ± 9% of the total wet deposition, respectively; the respective percentages in dry deposition were 58 ± 11% and 42 ± 11%. In this study, we used C/N: 6.625 in the Redfield ratio, and assumed a HMW and LMW ON utilization rates of 20% and 80%, respectively. The new production potentially supported by the ocean's external nitrogen supply provided through atmospheric input was calculated to be equivalent to 17.5 g C m−2 yr−1; specifically, atmospheric deposition could contribute 26.6% of the total new production in the southern ECS.

中文翻译：

---

干湿大气沉降中无机和有机氮物种的组成和供应：使用有机氮组成来计算来自大气的海洋外部氮通量

摘要 东海南部（ECS）干湿沉降在高分子量有机氮（HMW-ON）和低分子量有机氮（LMW-ON）的相对比例上存在较大差异。通过区分不同分子量的 ON，本研究提出了一种改进的计算方法，即干沉降和湿沉降对 ECS 南部表层海水新产量的贡献。本研究使用了 2014 年 1 月至 2014 年 12 月收集的来自 ECS 南部的 54 个雨水样本和 12 组大小分级的大气颗粒。溶解或水溶性样本经过超滤方法将 ON 分离为 HMW-ON 和 LMW-ON . ON 的总体平均浓度在湿沉积中为 56.5 ± 18.8 μM，在干沉积中为 117.0 nmol m-3。LMW-ON 和 HMW-ON 分别占总湿沉积的 82±9% 和 18±9%；干沉降的百分比分别为 58 ± 11% 和 42 ± 11%。在本研究中，我们在 Redfield 比率中使用 C/N：6.625，并假设 HMW 和 LMW ON 利用率分别为 20% 和 80%。通过大气输入提供的海洋外部氮供应可能支持的新产量计算相当于 17.5 g C m-2 yr-1；具体而言，大气沉降可占 ECS 南部总新产量的 26.6%。通过大气输入提供的海洋外部氮供应可能支持的新产量计算相当于 17.5 g C m-2 yr-1；具体而言，大气沉降可占 ECS 南部总新产量的 26.6%。通过大气输入提供的海洋外部氮供应可能支持的新产量计算相当于 17.5 g C m-2 yr-1；具体而言，大气沉降可占 ECS 南部总新产量的 26.6%。