MTA Centre for Ecological Research, Sustainable Ecosystems Group, Tihany, Hungary.
Doctoral School of Environmental Sciences, Eötvös Loránd University, Budapest, Hungary.
PLoS One. 2018 Oct 25;13(10):e0205343. doi: 10.1371/journal.pone.0205343. eCollection 2018.
The spatial response of epiphytic diatom communities to environmental stress was studied in a moderately saline wetland area located in the plain of Danube-Tisza Interfluve, Hungary. The area is characterised by World War II bomb crater ponds and can be regarded as an excellent ecological model system where the dispersion of species is slightly limited by distance. To study the effect of environmental variables on the communities, canonical correspondence analysis was applied. Salinity, pH, total suspended solids, total phosphorous and depth proved to be significant environmental drivers in this analysis. The ecological status of the ponds was assessed with Ziemann's halobity index, as the trophity-depending metric cannot be applied to these habitats (due to the naturally high phosphorus content). Ponds in "good" ecological status significantly differed from those appertaining to water quality category of "not-good" ecological status considering characteristic of natural astatic soda pans (e.g. salinity, pH, ammonium, total phosphorous concentration, nitrogen:phosphorous ratio and turbidity). The differences between epiphytic diatom communities inhabiting the ponds were detected using non-parametric multidimensional scaling. The samples formed three groups according to the types of ponds ("transparent", "transitional" and "turbid") based on the width of the macrophyte belt around them. Indicator species related to the ecological status of the ponds and diatom communities contributing to the separation of groups of ponds were identified. One of the indicator species differed from species already described. Light and scanning electron microscopy features and phylogenetic analyses based on three genes (18S and 28S rRNA genes, rbcL) proved that it was a new species of Nitzschia genus, closely related to Nitzschia frustulum and Nitzschia inconspicua. Therefore, description of a new species, Nitzschia reskoi Ács, Duleba, C.E.Wetzel & Ector is proposed. We concluded that the increasing abundance of Nitzschia reskoi was a signal of the degradation of the intermittent saline wetlands.
本研究以匈牙利多瑙河-蒂萨河间地平原的一个中度盐沼湿地为研究区，探讨了附生硅藻群落对环境胁迫的空间响应。该地区的特点是有二战时期的弹坑池塘，可以被视为一个极好的生态模型系统，其中物种的扩散仅受到距离的轻微限制。为了研究环境变量对群落的影响，本研究应用典范对应分析。结果表明，盐度、pH 值、总悬浮固体、总磷和水深是该分析中的重要环境驱动因素。本研究采用 Ziemann 的卤生性指数评估池塘的生态状况，因为基于营养依赖的度量标准不适用于这些栖息地（由于自然高磷含量）。“良好”生态状况的池塘与属于“不良”生态状况的池塘有显著差异，这是因为“良好”生态状况的池塘具有天然静态苏打湖的特征（如盐度、pH 值、铵、总磷浓度、氮磷比和浊度）。使用非参数多维尺度分析检测到栖息在池塘中的附生硅藻群落之间的差异。根据周围大型植物带的宽度，样本分为三组，即“透明”、“过渡”和“浑浊”池塘。鉴定了与池塘生态状况相关的指示种和对池塘分组有贡献的硅藻群落。其中一个指示种与已描述的物种不同。基于三个基因（18S 和 28S rRNA 基因、rbcL）的光和扫描电子显微镜特征和系统发育分析表明，它是一种新的窄形舟形藻属物种，与舟形藻属的脆杆藻和狭形舟形藻密切相关。因此，建议描述一种新的窄形舟形藻属物种，即 Resko 窄形舟形藻。我们得出的结论是，Resko 窄形舟形藻丰度的增加是间歇性盐沼湿地退化的信号。
