Physico-chemical dataset from an in situ mesocosm experiment simulating extreme climate events in Lake Geneva (MESOLAC)

This dataset corresponds to the physico-chemical parameters data series produced during the MESOLAC experimental project. The presented dataset is composed of: 1. In situ profiles (0-3m) of temperature, conductivitivy, pH, oxygen (concentration et saturation). 2. In situ measures of light spectral UV/VIS/IR irradiance (300-950 nm wavelength range) taken at 0, 0.25, 0.5, 1, 1.5, 2 and 2.5m. 3. Laboratory chemical analysis of samples collected at 0 and 2 m (conductivity, pH, total alkalinity, NH4, NO2, NO3, Ntot, Npart, PO4, Ptot, Ppart, Ctot, Cpart-org, Cpart-tot, Cl, SO4, SiO2). 4. Laboratory analysis of pigments extracted from samples collected at 0 and 2 m (Chla, Chlc, carotenoids, phaeopigments). The experiment consisted of nine pelagic mesocosms (about 3000 L, 3m depth) deployed in July 2019 in Lake Geneva near the shore of Thonon les Bains, France, to simulate predicted climate scenarios (i.e. extreme events) and assess the response of pelagic communities, ecosystem functioning and resilience. The experiment lasted 4 weeks (July 4 – 30, 2019) and the design included three treatments each replicated 3 times: a control treatment (no treatment applied – named C) and two different treatments simulating extreme weather events of different intensities. The high intensity treatment (named H) aimed at reproducing short and intense weather events such as violent storms. It consisted of a short-term intense stress applied during the first week, with high pulse of dissolved organic carbon (DOC 5x increased concentration compared to the control), light reduction up the 95% and water column manual mixing daily for 15 mins. The medium intensity treatment (named M), simulated less intense and more prolonged exposures such as during flood events. It was maintained during the 4 weeks and consisted of 1.5x increased concentration of DOC compared to the control, light reduction up to 70 % and water column manual mixing daily for 5 mins. During the experiment, physical parameters were measured twice a week and samples were collected at the same date at the depth of 0 and 2m for subsequent chemical laboratory analyses. These data are presented in the dataset file, ordered by sampling event (numbered from S1 to S8), treatment (Control-C, High-H and Medium-M) and replicates (1 to 3). For each time point the measured parameters are listed in columns, missing data are marked as NA.

本数据集对应MESOLAC实验项目（MESOLAC）产生的理化参数时间序列数据。本数据集包含以下内容：
1. 0~3米深度的原位剖面数据，涵盖温度、电导率、pH、溶解氧（浓度与饱和度）；
2. 在0、0.25、0.5、1、1.5、2、2.5米处原位测量的紫外/可见/红外（UV/VIS/IR）光谱辐照度，测量波长范围为300~950 nm；
3. 对0米与2米深度采集的样品开展的实验室化学分析，检测指标包括电导率、pH、总碱度、NH4、NO2、NO3、总氮（Ntot）、颗粒态氮（Npart）、PO4、总磷（Ptot）、颗粒态磷（Ppart）、总碳（Ctot）、颗粒有机碳（Cpart-org）、总颗粒碳（Cpart-tot）、Cl、SO4、SiO2；
4. 对0米与2米深度采集的样品提取的色素开展的实验室分析，检测指标包括叶绿素a（Chla）、叶绿素c（Chlc）、类胡萝卜素、脱镁色素（phaeopigments）。

本实验共设置9个浮游中型实验生态系（pelagic mesocosms），单个生态系体积约3000升，水深3米，于2019年7月部署在法国托农莱班（Thonon les Bains）附近的日内瓦湖沿岸，旨在模拟预测的气候情景（即极端事件），并评估浮游群落、生态系统功能与恢复力的响应。实验周期为4周（2019年7月4日至7月30日），实验设计包含3种处理组，每组均重复3次：对照组（无额外干预，编号C），以及两组模拟不同强度极端天气事件的处理组。
- 高强度处理组（编号H）：旨在重现短时强极端天气事件（如强风暴），于实验第一周施加短期强胁迫：溶解有机碳（dissolved organic carbon, DOC）浓度较对照组提升5倍，光照削弱幅度达95%，每日对水柱进行15分钟人工混合。
- 中强度处理组（编号M）：旨在模拟强度更低、持续时间更长的暴露情景（如洪水事件），该处理贯穿全部4周实验：溶解有机碳浓度较对照组提升1.5倍，光照削弱幅度达70%，每日对水柱进行5分钟人工混合。

实验期间，物理参数每周测量两次，且于相同采样日期在0米与2米深度采集样品，用于后续实验室化学分析。本数据集文件中的数据按采样事件（编号S1至S8）、处理组（对照组C、高强度组H、中强度组M）以及重复样本（1至3）进行排序。每个时间点的测量参数以列形式呈现，缺失数据以NA标记。