Abstract. Since the beginning of the industrial revolution, atmospheric carbon dioxide (CO2) concentrations have risen steadily and have induced a decrease of the averaged surface ocean pH by 0.1 units, corresponding to an increase in ocean acidity of about 30 %. In addition to ocean warming, ocean acidification poses a tremendous challenge to some marine organisms, especially calcifiers. The need for long-term oceanic observations of pH and temperature is a key element to assess the vulnerability of marine communities and ecosystems to these pressures. Nearshore productive environments, where a large majority of shellfish farming activities are conducted, are known to present pH levels as well as amplitudes of daily and seasonal variations that are much larger than those observed in the open ocean. Yet, to date, there are very few coastal observation sites where these parameters are measured simultaneously and at high frequency. To bridge this gap, an observation network was initiated in 2021 in the framework of the CocoriCO2 project. Six sites were selected along the French Atlantic and Mediterranean coastlines based on their importance in terms of shellfish production and the presence of high- and low-frequency monitoring activities. At each site, autonomous pH sensors were deployed, both inside and outside shellfish production areas, next to high-frequency CTD (conductivity–temperature–depth) probes operated through two operating monitoring networks. pH sensors were set to an acquisition rate of 15 min, and discrete seawater samples were collected biweekly in order to control the quality of pH data (laboratory spectrophotometric measurements) as well as to measure total alkalinity and dissolved inorganic carbon concentrations for full characterization of the carbonate system. While this network has been up and running for more than 2 years, the acquired dataset has already revealed important differences in terms of pH variations between monitored sites related to the influence of diverse processes (freshwater inputs, tides, temperature, biological processes). Data are available at https://doi.org/10.17882/96982 (Petton et al., 2023a).

中文翻译：

---

法国沿海碳酸盐系统监测网络：CocoriCO2 数据集

摘要。自工业革命开始以来，大气中二氧化碳（CO2）浓度稳步上升，导致海洋表面平均pH值下降0.1个单位，相当于海洋酸度增加约30%。除了海洋变暖之外，海洋酸化对一些海洋生物，特别是钙化物构成了巨大的挑战。需要对海洋 pH 值和温度进行长期观测，这是评估海洋群落和生态系统对这些压力的脆弱性的关键因素。大部分贝类养殖活动都在近岸生产环境中进行，众所周知，其 pH 水平以及每日和季节性变化的幅度比在公海中观察到的要大得多。然而，迄今为止，很少有沿海观测站能够同时、高频地测量这些参数。为了弥补这一差距，2021 年在 CocoriCO2 项目框架内启动了一个观测网络。根据其在贝类生产方面的重要性以及高频和低频监测活动的存在，在法国大西洋和地中海海岸线选择了六个地点。在每个地点，贝类生产区内外都部署了自主 pH 传感器，旁边是通过两个运行监测网络操作的高频 CTD（电导率-温度-深度）探头。 pH 传感器的采集速率设置为 15 分钟，每两周收集一次离散海水样品，以控制 pH 数据的质量（实验室分光光度测量）并测量总碱度和溶解的无机碳浓度，以全面表征碳酸盐体系。虽然该网络已经启动并运行了 2 年多，但所获取的数据集已经揭示了与不同过程（淡水输入、潮汐、温度、生物过程）的影响相关的监测地点之间 pH 值变化的重要差异。数据可在 https://doi.org/10.17882/96982 上获取（Petton 等人，2023a）。