SO RadeHydro-Point B time series : monitoring a fixed point in a coastal ecosystem, bay of Villefranche sur mer, Ligurian Sea (Western Mediterranean)

the bay of villefranche-sur-mer (french riviera) is a medium-sized bay (2 miles long by 0.8 wide) characterized by great depth (> 300 m at its mouth) and the absence of a continental shelf. it is sheltered from the prevailing east and west winds this oligotrophic to mesotrophic site is located in a highly urbanized area, subjected to seasonal anthropogenic influences: cruise ships, intense yachts traffic, increases of population. the roya (26 km e), paillon (4 km w) and var (30 km w) rivers are the closest freshwater inflows, with strong seasonal variability. this sampling site is exceptional in that, thanks to the absence of a continental shelf and the northerly current, oceanic organisms (e.g. gelatinous organisms) reach the coast via the offshore water masses that enter the bay. this privileged location has enabled a unique hydrological monitoring service to set up at a fixed station (point b; 43°41.00n/7°.19.000e; 80 m depth) near the institut de la mer in villefranche-sur-mer (imev) since 1957, and providing year-round temporal coverage with weekly sampling intervals.weekly samplings are conducted either at two (1 and 50m) or six (1, 10, 20, 30, 40, 50, 75 m) sampling depths. a multi-parameter autonomous profiler is deployed at each sampling time for the whole water column, and at each sampling depth, water samples are analyzed for a panel of biochemical oceanographic parameters (temperature, salinity, nutrients, ph, isotopes, suspended matter, cop, nop, chlorophyll a biomass; cytometry since 2009).in addition to sampling at point b, to characterize the regional autumn-winter mixing layer and winter water mass, weekly profiles of bio-physical parameters (temperatures, salinity, fluorescence, dissolved oxygen) at point b+ (43°41.00n/7°18.000e; 150 m) and at point c (43°40.550n/7°18.600e; 300 m depth), are carried out on the same day as point b, if weather permitting. parallel to the biogeochemical monitoring, zooplankton and microphytoplankton samples (as part of the phytobs and rephy networks) are taken, allowing us to follow the fluctuations of the communities at the multi-decadal scale. high-frequency monitoring (coast hf) of temperature, salinity and fluorescence measurements is also carried out from the autonomous eol platform located a few tens of meters from point b. thus, we have an original series of more than 60 years of biological, physical and chemical variables at the same sampling point.all these monitorings, carried out on the station boat with her staff, are provided by the observation staff of the imev with a contribution of staff from the laboratory of oceanology of villefranche (lov).

位于法国里维埃拉的法尔内斯湾（维尔弗朗什-sur-mer湾）是一座中等规模的港湾（长2英里，宽0.8英里），以其深邃的水域（入口处深度超过300米）和缺乏大陆架而著称。该寡营养至中营养型区域地处高度城市化的地带，受季节性人为因素影响显著：包括游轮、密集的游艇交通以及人口增长。罗亚河（东26公里）、帕伊翁河（西4公里）和瓦尔河（西30公里）是最近的淡水补给源，具有强烈的季节性变化。此采样点之所以独特，在于大陆架的缺失和北向洋流的共同作用，使得海洋生物（例如凝胶状生物）能够通过进入湾内的海流水团抵达海岸。这一得天独厚的地理位置使得自1957年以来，在维尔弗朗什-sur-mer（IMEV）的海洋研究所附近设立了一个固定监测站（B点；43°41.00N/7°19.000E；80米深度），提供全年无休的时空覆盖，每周进行采样。每周采样深度为两个（1米和50米）或六个（1米、10米、20米、30米、40米、50米、75米）。在每次采样时，部署多参数自主剖面仪对整个水柱进行监测，并在每个采样深度，对一系列生化海洋学参数（温度、盐度、营养物质、pH值、同位素、悬浮物质、溶解有机碳、氮氧化物、叶绿素a生物量；自2009年起进行细胞计数）进行分析。除了在B点进行采样外，为表征区域秋季冬季混合层和冬季水团，如果天气允许，当天在同一时间对B+点（43°41.00N/7°18.000E；150米）和C点（43°40.550N/7°18.600E；300米深度）的生物物理参数（温度、盐度、荧光、溶解氧）进行每周剖面监测。与生物地球化学监测并行，我们还采集浮游动物和微型浮游植物样本（作为phytobs和rephy网络的一部分），以追踪多十年尺度上的群落波动。此外，从位于B点数十米处的自主风能平台进行高频监测（海岸高频），对温度、盐度和荧光进行测量。因此，我们拥有超过60年的生物、物理和化学变量原始数据系列，这些数据在同一采样点收集。IMEV的观测人员及其来自维尔弗朗什海洋实验室（LOV）的员工，乘坐观测船，提供所有这些监测工作。