High frequency monitoring of water quality in the North-Aquitanian estuaries: data from the Portets station

The French Atlantic coast hosts numerous macrotidal and turbid estuaries that flow into the Bay of Biscay that are natural corridors for migratory fishes. The two best known are those of the Gironde and the Loire. However, there are also a dozen estuaries set geographically among them, of a smaller scale. The physico-chemical quality of estuarine waters is a necessary support element for biological life and determines the distribution of species, on which many ecosystem services (e.g. professional or recreational fishing) depend. With rising temperatures and water levels, declining precipitation and population growth projected for the New Aquitaine region by 2030, the question of how the quality and ecological status of estuarine waters will evolve becomes increasingly critical. The MAGEST (Mesures Automatisées pour l’observation et la Gestion des ESTuaires nord aquitains) high-frequency monitoring of key physico-chemical parameters was first developed in the Gironde estuary in 2004 ; the Seudre and Charente estuaries were instrumented late 2020. First based on real-time automated systems, MAGEST is now equipped by autonomous multiparameter sensors. Depending of the stations, an optode is also deployed to secure dissolved oxygen measurement. By the end of 2020, MAGEST had 12 instrumented sites. Portets is a measuring station located in the upper Gironde estuary (Garonne subestuary, about 20 km upstream of the Bordeaux metropolis.

法国大西洋沿岸分布着众多汇入比斯开湾的大潮差浑浊河口，它们是洄游鱼类的天然洄游通道。其中最知名的当属吉伦特（Gironde）河口与卢瓦尔（Loire）河口。除此之外，该区域地理范围内还分布有十余座规模较小的河口。河口水体的理化质量是生物生存的必要支撑条件，同时决定了物种的分布格局，而诸多生态系统服务（如商业捕捞或休闲垂钓）均依托于此得以存续。到2030年，新阿基坦大区预计将面临气温与水位上升、降水量减少以及人口增长的多重压力，因此河口水体质量与生态状况的演化趋势问题愈发关键。MAGEST (Mesures Automatisées pour l’observation et la Gestion des ESTuaires nord aquitains) 针对关键理化参数的高频监测方案，最初于2004年在吉伦特河口搭建；2020年末，瑟德尔（Seudre）河口与夏朗德（Charente）河口也完成了监测设备的布设。该系统最初基于实时自动化监测系统搭建，如今已换装自主式多参数传感器。根据站点配置的不同，部分站点还部署了光学溶解氧传感器，以保障溶解氧的测量准确性。截至2020年末，MAGEST系统共设有12个监测点位。其中，波尔泰（Portets）站是位于吉伦特河口上游（加龙（Garonne）子河口，距离波尔多都会区上游约20公里）的监测站点。