In this study, a terrestrial-estuarine-ocean biogeochemical modeling system (DLEM-ChesROMS-ECB) was used to investigate the impact of prevailing spring-to-summer winds on hypoxia in Chesapeake Bay. The modeling system was run continuously from 1985 to 2005 under realistic wind conditions. Correlation analysis based on the 21-year simulation results revealed that the durations of spring northeasterly winds and summer southerly winds were both positively correlated with the volume of summer hypoxia. Conversely, the duration of summer northeasterly winds was negatively correlated with hypoxia. We then conducted multiple idealized sensitivity experiments to explore the underlying mechanisms governing these relationships. The results indicated that prolonged northeasterly winds in spring promoted along-channel transport of oxygen-consuming materials from the upper to the lower Bay, leading to a higher level of oxygen consumption via water column respiration (WCR). This may have led to more severe hypoxic events in the following summer. During summer, northeasterly winds increase vertical mixing as the riverine freshwater is mostly restricted to the western bank, thereby preventing the occurrence of hypoxia. Furthermore, strengthened vertical mixing increased light availability, resulting more nutrients taken up by phytoplankton. Consequently, more dissolved oxygen was produced. When comparing the differences in mass budget terms under southerly winds, the oxygen production accounted for approximately 60% of the WCR. In contrast to previous studies that mostly examined the short-term episodic effects of wind, our study underscores the importance of the impact of prolonged seasonally variable winds and biological feedback on hypoxic volume in Chesapeake Bay, which helps in the development of appropriate nutrient management strategies in a changing climate.

中文翻译：

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季节性风况对切萨皮克湾缺氧演变的影响：陆地-河口-海洋生物地球化学模拟系统的结果

在这项研究中，利用陆地-河口-海洋生物地球化学模拟系统（DLEM-ChesROMS-ECB）来研究春夏盛行风对切萨皮克湾缺氧的影响。该建模系统从 1985 年到 2005 年在真实的风力条件下连续运行。根据21年的模拟结果进行相关分析发现，春季东北风和夏季南风持续时间均与夏季缺氧量呈正相关。相反，夏季东北风的持续时间与缺氧呈负相关。然后，我们进行了多次理想化敏感性实验，以探索控制这些关系的潜在机制。结果表明，春季持续的东北风促进了耗氧物质从上湾到下湾的沿航道输送，导致水柱呼吸（WCR）的耗氧量更高。这可能导致第二年夏天发生更严重的缺氧事件。夏季，东北风增加了垂直混合，河流淡水大多局限于西岸，从而防止了缺氧的发生。此外，加强垂直混合增加了光的可用性，导致浮游植物吸收更多的营养物质。因此，产生了更多的溶解氧。当比较南风下质量预算项的差异时，氧气产量约占 WCR 的 60%。与之前主要考察风的短期偶发效应的研究相比，我们的研究强调了长期季节性变化的风和生物反馈对切萨皮克湾缺氧量的影响的重要性，这有助于制定适当的营养管理策略在不断变化的气候中。