The discharge of rivers and the subsequent dispersion of their plumes play a pivotal role in the biogeochemical cycling of the Arctic Ocean. Based on the data collected during annual transects conducted in the autumn period (September-October) from 2015-2020, this study explores the effect of River Lena plume dispersion on the seasonal and interannual changes in the hydrophysical and biogeochemical structure of the southeastern Laptev Sea. The temperature-salinity relationship (T-S), Redfield ratio and multiparameter cluster analysis were used to investigate variations in the water mass structure along the transect. The results revealed that the plume’s interannual and seasonal spreading patterns play a crucial role in regulating the local physical, biogeochemical, and biological processes in the southern Laptev Sea. During September-October, the hydrochemical water mass structure along the transects shifted from highly stratified to unstratified as the plume’s mixing intensity increased. Anomalous hydrochemical distributions were observed due to coastal upwelling, which was primarily characterized by high total alkalinity and nitrate levels, and low organic phosphorus, nitrite, and ammonia levels in the seawater. Wind and cold weather conditions drive deep vertical mixing of seawater, causing the resuspension of bottom sediment and the subsequent enrichment of bottom water by nutrients. Multi-parameter cluster analysis is used to describe the details of water mass structures in the highly dynamic southern Laptev Sea, with water mass structures typically undergoing significant changes within two weeks between September and October. The migration and transformation of water masses throughout the seasons are influenced by the volume of river discharge, fall-winter cooling, and atmospheric circulation patterns. Furthermore, the general atmospheric circulation is confirmed to be the primary cause of the interannual variation in the spread of the Lena River plume over the southeast Laptev Sea.

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2015-2020年拉普捷夫海生物地球化学结构与勒拿河羽流相关

河流的排放和随后的羽流扩散在北冰洋的生物地球化学循环中起着举足轻重的作用。本研究基于 2015-2020 年秋季（9 月-10 月）年度横断面收集的数据，探讨了勒拿河羽流散布对拉普捷夫海东南部水文物理和生物地球化学结构的季节性和年际变化的影响. 温度-盐度关系 (TS)、Redfield 比率和多参数聚类分析用于研究横断面上水团结构的变化。结果表明，羽流的年际和季节性传播模式在调节拉普捷夫海南部的当地物理、生物地球化学和生物过程中起着至关重要的作用。9-10月期间，随着羽流混合强度的增加，沿横断面的水化学水团结构从高度分层转变为非分层。由于沿海上升流，观察到异常的水化学分布，其主要特征是海水中总碱度和硝酸盐含量高，有机磷、亚硝酸盐和氨含量低。风和寒冷的天气条件推动海水深度垂直混合，导致底部沉积物重新悬浮，随后底部水被营养物富集。多参数聚类分析用于描述高度动态的拉普捷夫海南部水团结构的细节，水团结构通常在 9 月至 10 月的两周内发生显着变化。水团在整个季节的迁移和转化受河流流量、秋冬降温和大气环流模式的影响。此外，一般大气环流被证实是拉普捷夫海东南部勒拿河羽流扩散年际变化的主要原因。