Estuaries are productive ecosystems that support extensive vertebrate and invertebrate communities, but some have suffered from an accelerated pace of acidification in their bottom waters. A major challenge in the study of estuarine acidification is strong temporal and spatial variability of carbonate chemistry resulting from a wide array of physical forces such as winds, tides and river flows. Most past studies of carbonate system dynamics were limited to the along channel direction, while lateral dynamics received less attention. Recent observations in Chesapeake Bay showed strong lateral asymmetry in the partial pressure of carbon dioxide (pCO2) and air-sea CO2 flux during a single wind event, but comparable responses to different wind events has yet to be investigated. In this work, a coupled hydrodynamic-carbonate chemistry model is used to understand wind-driven variability in the estuarine carbonate system. It is found that wind-driven lateral upwelling ventilates high DIC (Dissolved Inorganic Carbon) and CO2 deep water and raises surface pCO2, thereby modifying the air-sea CO2 flux. The upwelling also advects low pH water onto the adjacent shoals and reduces the aragonite saturation state Ωarag in these shallow water environments, producing large temporal pH fluctuations and low pH events. Regime diagrams are constructed to summarize the effects of wind events on temporal pH and Ωarag fluctuations and the lateral gradients in DIC, pH, and pCO2 in the estuary. This modeling study provides a mechanistic explanation for the observed wind-driven lateral variability in DIC and pCO2 and reproduces large pH and Ωarag fluctuations that could be driven by physical forcing. Given that current and historic mainstem Bay oyster beds are located in shallow shoals affected by this upwelling, a large fraction of the oyster beds (100–300 km2) could be exposed to carbonate mineral under-saturated (Ω

中文翻译：

---

风驱动横向上升流对河口碳酸盐化学的影响

河口是多产的生态系统，支持广泛的脊椎动物和无脊椎动物群落，但有些河口的底层水域酸化速度加快。河口酸化研究的一个主要挑战是由风、潮汐和河流流动等多种物理力引起的碳酸盐化学的强烈时空变异性。以往对碳酸盐岩系统动力学的研究大多局限于沿河道方向，而横向动力学研究较少。最近在切萨皮克湾的观测表明，在单个风事件期间，二氧化碳分压 (pCO2) 和海气 CO2 通量存在强烈的横向不对称性，但对不同风事件的可比响应尚待研究。在这项工作中，耦合的流体动力-碳酸盐化学模型用于了解河口碳酸盐系统中风驱动的变异性。研究发现，风驱动的横向上升流使高 DIC（溶解无机碳）和 CO2 深水通风，并提高了表面 pCO2，从而改变了海气 CO2 通量。上升流还将低 pH 值水平流到相邻的浅滩上，并降低了这些浅水环境中的文石饱和状态 Ωarag，产生大的时间 pH 值波动和低 pH 值事件。构建了制度图来总结风事件对时间 pH 值和 Ωarag 波动以及河口 DIC、pH 和 pCO2 的横向梯度的影响。该建模研究为观察到的 DIC 和 pCO2 中观察到的风驱动横向变化提供了机械解释，并再现了可能由物理强迫驱动的大 pH 值和 Ωarag 波动。鉴于当前和历史上的主干湾牡蛎床位于受此上升流影响的浅滩中，大部分牡蛎床（100-300 平方公里）可能暴露于不饱和碳酸盐矿物（Ω