Marine environmental station database of Daoulas bay

Located in Northwestern France, the Bay of Brest constitutes a coastal macrotidal and semi-enclosed ecosystem (total area of 180 km2, maximum tidal amplitude of 8 m, average depth of 8 m) influenced by both freshwater inputs from rivers (to its east-side) and fast mixing exchanges with the Atlantic Ocean through a narrow (1.8 km of wide) and deep (40 m) channel (to its west-side). The average flushing time of the system is around 25 days. The shallowness of the bay and the water mixing induced by tidal currents prevent the ecosystem from vertical stratification and nutrient accumulation and therefore limit eutrophication. This environment is still very rich and shelters numerous species, macrobenthic communities and remarkable habitats (for instance: maerl beds, scallops and brittlestars sandy-shelly muds, flat oysters beds associated with black scallops, slipper limpet mixed sediments, zostera beds, intertidal pacific oyster population...). Nevertheless, this ecosystem is also under the pressure of human activities: the north of the system shelters a population of 400 000 inhabitants whereas the south is more influenced by intensive agricultural activities. Marine resources are also intensively exploited by professional fishing, shellfish aquaculture and recreational activities (diving, fishing and picking). One of the most productive area within the bay of Brest is the Daoulas bay – a very shallow embayment (max depth 8 m) - that receives the freshwater inputs of « The mignonne » river. This small bay harbours various aquaculture and fishing activities and also a protected marine area managed by Natura 2000. To better understand physical and biological processes within this bay and their evolution under the context of global change, an observation station has been set up since 2006. At the beginning, only water temperature was measured with the help of automatic probes. Nowadays, this observatory system includes a real time monitoring of the following environmental parameters: temperature, salinity, in vivo fluorescence (chlorophyll a), oxygen concentration, pH and turbidity. Data are acquired with probes fixed on metallic structure at 50 cm over the sediment bottom on the foreshore in the intertidal zone. Since 2006, several type of probes were used and are listed in the data: EBI 85 from Global Water (http://www.globalw.com) ; DS5 Hydrolab from OTT (http://www.ott.com) ; SP2T, STPS or SMATCH from NKE (http://www.nke-instrumentation.fr). For each of them, temperature and salinity accuracies are also available. Time frequency of recording can differ from one probe to another but tends to be 15 minutes.

布雷斯特湾（Bay of Brest）位于法国西北部，是一处潮差显著的沿海半封闭生态系统（coastal macrotidal and semi-enclosed ecosystem），总面积180平方千米，最大潮差8米，平均水深8米。该生态系统同时受到东侧河流淡水输入，以及西侧宽1.8千米、深40米的狭窄水道与大西洋的快速水体交换的双重影响，平均换水周期约25天。海湾的浅水环境与潮流引发的水体混合，有效阻止了该生态系统出现垂直分层与营养盐积累，进而抑制了富营养化（eutrophication）的发生。该海域仍具有极高的生物多样性，孕育了丰富的物种种群、大型底栖生物群落（macrobenthic communities）与特色生境，例如：珊瑚藻床（maerl beds）、扇贝与阳遂足（brittlestars）砂质泥底生境、与黑扇贝共生的扁平牡蛎床、履螺混合沉积物生境、鳗草床（zostera beds）、潮间带太平洋牡蛎种群等。
尽管如此，该生态系统仍面临人类活动的多重胁迫：海湾北侧聚居着40万人口，南侧则受集约化农业活动影响更为显著；海洋资源同时受到专业捕捞、贝类养殖以及休闲活动（潜水、垂钓与贝类采集）的高强度开发利用。布雷斯特湾内生产力最高的区域之一为道拉斯湾（Daoulas bay）——这是一处最大水深仅8米的极浅海湾，接纳了米农河（The mignonne river）的淡水输入。该小海湾兼具多种养殖与捕捞活动，同时也是由Natura 2000（欧盟自然保护区网络）管理的海洋保护区域。
为深入解析该海湾内的物理与生物过程及其在全球变化背景下的演化规律，研究团队于2006年起设立了长期观测站。建站初期，仅通过自动监测探头（automatic probes）采集水温数据。如今，该观测系统已实现对以下环境参数的实时监测（real time monitoring）：水温、盐度、活体荧光（in vivo fluorescence，叶绿素a）、溶解氧浓度（oxygen concentration）、pH值与浊度（turbidity）。数据由安装于潮间带前滩沉积物底床（sediment bottom）上方50厘米处的金属结构上的监测探头采集。自2006年以来，观测使用过多款监测探头，具体型号详见数据集：Global Water公司的EBI 85（官网：http://www.globalw.com）；OTT公司的DS5 Hydrolab（官网：http://www.ott.com）；NKE公司的SP2T、STPS或SMATCH（官网：http://www.nke-instrumentation.fr）。各探头的水温与盐度测量精度均有公开记录。不同探头的采样时间频率存在差异，目前普遍采用15分钟的采样间隔。