In this study, the influence of sea-level rise (SLR) on seasonal hypoxia and phytoplankton production in Chesapeake Bay is investigated using a 3D unstructured grid model. Three SLR scenarios (0.17, 0.5, and 1.0 m) were conducted from 1991 to 1995. Results show that the summer hypoxic volume (HV) increases about 2%, 8%, and 16%, respectively, for these three scenarios, compared with Base Scenario. The contributions of physical and biological processes on the increase in the HV were analyzed. With the projected SLR, enhanced gravitational circulation transports more oxygen-rich water in the bottom layer from the mouth. However, the pycnocline moves upwards along with increasing water depth, which largely prolongs the time for dissolved oxygen (DO) to be transported to the bottom. The altered physical processes contribute greatly to a larger HV bay-wide. Besides, SLR increases the whole Bay phytoplankton production, with a larger increase in shallow areas (e.g., 53% in areas with depth <1 m under SLR of 0.5 m). Enhanced light availability is suggested to be the major driver of blooming phytoplankton under SLR in shallow areas. While increased DO production over the euphotic zone is mostly released to the atmosphere and transported downstream, the increase in settled organic matter greatly promotes DO consumption in the water column. The increased respiration is another major cause of the HV increase besides the physical contributions.

中文翻译：

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海平面上升对切萨皮克湾缺氧和浮游植物生产的影响：模型预测和评估

在这项研究中，使用 3D 非结构化网格模型研究了海平面上升 (SLR) 对切萨皮克湾季节性缺氧和浮游植物生产的影响。从 1991 年到 1995 年进行了三种 SLR 情景（0.17、0.5 和 1.0 m）。结果表明，与基本情景。分析了物理和生物过程对 HV 增加的贡献。有了预计的SLR，增强的重力循环从口中输送了更多底层的富氧水。然而，随着水深的增加，密度跃层向上移动，这大大延长了溶解氧（DO）输送到底部的时间。改变后的物理过程极大地促进了更大的 HV 跨区范围。此外，SLR增加了整个海湾浮游植物的产量，浅水区增加较多（如SLR为0.5 m时，深度<1 m的区域增加了53%）。增强的光照可用性被认为是浅水区域 SLR 下浮游植物开花的主要驱动力。虽然透光区增加的 DO 产量大部分被释放到大气中并输送到下游，但沉降有机物的增加极大地促进了水体中 DO 的消耗。除了物理贡献外，呼吸增加是 HV 增加的另一个主要原因。增强的光照可用性被认为是浅水区域 SLR 下浮游植物开花的主要驱动力。虽然透光区增加的 DO 产量大部分被释放到大气中并输送到下游，但沉降有机物的增加极大地促进了水体中 DO 的消耗。除了物理贡献外，呼吸增加是 HV 增加的另一个主要原因。增强的光照可用性被认为是浅水区域 SLR 下浮游植物开花的主要驱动力。虽然透光区增加的 DO 产量大部分被释放到大气中并输送到下游，但沉降有机物的增加极大地促进了水体中 DO 的消耗。除了物理贡献外，呼吸增加是 HV 增加的另一个主要原因。