A floristic survey was performed on a temporary pond, “Laqui du Seignavoux”, situated in the Mont-Dore massif of the French Massif Central, between 2017 and 2019. Except in 2017, each year, we performed four sampling campaigns from April/May to December. Water samples and diatoms were collected. The temporary pond evolved from a poorly mineralized ecosystem due to snow, inducing oligotrophic and oligosaprobic water, well oxygenated in spring, to a more mineralized, less oxygenated, eutrophic–hypereutrophic, and polysaprobic environment in summer. This change in abiotic conditions was found to be linked to the presence of cattle, beginning in May, that trample and excrete in the pond, leading to higher ammonium and nitrate concentrations. During this period, the dominant species were Pinnularia sp., Nitzschia palea, and Nitzschia palea var. tenuirostris. In spring and winter, different species of Eunotia dominated the community such as Eunotia pseudogroenlandica. Finally, light microscopy (LM) and scanning electron microscopy (SEM) observations on a new species of the genus Pinnularia from the temporary pond are presented and the ecological preferences are discussed.

中文翻译：

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位于Massif du Sancy山脉（法国马西夫中部）的临时池塘中硅藻的时间演变和新Pinnularia物种的描述

在2017年至2019年之间，对位于法国地块中部Mont-Dore地块的临时池塘“ Laqui du Seignavoux”进行了植物学调查。除2017年外，每年从4月/ 5月起进行四次采样活动到十二月。收集水样和硅藻。临时池塘从由于积雪导致的矿化程度差的生态系统演变而来，诱导了春季富氧的贫营养水和低脂富氧水，到了夏季，矿化度更高，含氧量较少，富营养化-富营养化和多腐质环境。发现非生物条件的这种变化与从5月开始的牛的存在有关，牛在池塘中被践踏和排泄，从而导致较高的铵和硝酸盐浓度。在此期间，优势种为Pinnularia sp。，Nitzschia palea和Nitzschia palea var。腱线虫。在春季和冬季，诸如Eunotia pseudogroenlandica之类的Eunotia物种居于主导地位。最后，从临时池塘的新物种羽衣藻的光学显微镜（LM）和扫描电子显微镜（SEM）的观察结果进行了介绍，并讨论了其生态学偏好。