Evaluating the role of long-term anthropogenic changes on dissolved oxygen (DO) in coastal systems is often a challenge due to variability in a system and measurement sensitivity to spatial and temporal trends. Physical processes can significantly modify the DO variability and act as a major driver of uncertainty when it comes to quantifying the bio-chemical changes associated with the DO budget. Stratification has been observed to be a dominant factor in controlling the hypoxic conditions that can develop in Mobile Bay, AL, a shallow highly stratified estuary prone to episodic hypoxia. Using CTD transect data and long-term water quality monitoring stations the variability of DO was examined throughout Mobile Bay. This study examined the physical drivers of these trends and highlighted the role stratification, temperature, and advection play in driving the bay wide variability. Under stable conditions, the spatial trend in Mobile bay will reflect the along-estuary gradient. When stable conditions don't occur due to random episodic mixing events and cross estuary exchange, the Bay can be driven by a number of factors: the along-estuary gradients, time since the previous mixing event, level of stratification, and biochemical oxygen demand. The combination of these elements provides an increased understanding of the complex dynamics driving low DO in this system. Long-term trends show the DO is decreasing in Mobile Bay based on changes in DO in the shipping channel, northern region, and Bon Secour region.

由于系统的可变性和测量对空间和时间趋势的敏感性，评估长期人为变化对沿海系统中溶解氧 (DO) 的作用通常是一项挑战。在量化与 DO 预算相关的生化变化时，物理过程可以显着改变 DO 的可变性，并成为不确定性的主要驱动因素。已观察到分层是控制可在阿拉巴马州莫比尔湾发展的缺氧条件的主要因素，该地区是一个容易发生间歇性缺氧的浅层高度分层的河口。使用 CTD 横断面数据和长期水质监测站，在整个莫比尔湾检查了溶解氧的变化。这项研究检查了这些趋势的物理驱动因素，并强调了角色分层、温度、平流作用在推动海湾范围内的变化。在稳定条件下，莫比尔湾的空间趋势将反映沿河口的梯度。当由于随机偶发性混合事件和跨河口交换而没有出现稳定条件时，海湾可能受到许多因素的驱动：沿河口的梯度、自上次混合事件以来的时间、分层水平和生化需氧量. 这些元素的组合提供了对该系统中驱动低溶解氧的复杂动力学的更多理解。长期趋势表明，根据航道、北部地区和 Bon Secour 地区 DO 的变化，莫比尔湾的 DO 正在下降。由于随机偶发性混合事件和跨河口交换而发生，海湾可能受多种因素驱动：沿河口梯度、自上次混合事件以来的时间、分层水平和生化需氧量。这些元素的组合提供了对该系统中驱动低溶解氧的复杂动力学的更多理解。长期趋势表明，根据航道、北部地区和 Bon Secour 地区 DO 的变化，莫比尔湾的 DO 正在下降。由于随机偶发性混合事件和跨河口交换而发生，海湾可能受多种因素驱动：沿河口梯度、自上次混合事件以来的时间、分层水平和生化需氧量。这些元素的组合提供了对该系统中驱动低溶解氧的复杂动力学的更多理解。长期趋势表明，根据航道、北部地区和 Bon Secour 地区 DO 的变化，莫比尔湾的 DO 正在下降。这些元素的组合提供了对该系统中驱动低溶解氧的复杂动力学的更多理解。长期趋势表明，根据航道、北部地区和 Bon Secour 地区 DO 的变化，莫比尔湾的 DO 正在下降。这些元素的组合提供了对该系统中驱动低溶解氧的复杂动力学的更多理解。长期趋势表明，根据航道、北部地区和 Bon Secour 地区 DO 的变化，莫比尔湾的 DO 正在下降。