The colonisation patterns of diatom assemblages were studied on artificial substrates in lowland streams with different urban pollution levels. Density, diversity, colonisation rates, ecological guilds and cell size classes of the assemblage at each of two sites were followed for 1 week. In addition, assemblages growing on glass, in natural epipelic biofilm and in water were compared at each site. At both sites, diatom colonisation on glass substrates had already started after 30-min exposure. At the less polluted site, total diatom density was higher, along with the proportion of low-profile and motile species, and there was a higher amount of diatoms in size class 5 (>1500μm3). At the more polluted site, species from the high-profile guild and size class 3 (300–599μm3) dominated. Ecological traits (ecological guilds and size class) were not sensitive enough descriptors of early colonisation in nutrient-rich lowland, but the largest cells constituted the first settlers. The results show that the assemblage developed on artificial substrata was a good proxy of the composition in the sediment.

中文翻译：

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污染对城市低地溪流人工基质早期硅藻定植的影响

在具有不同城市污染水平的低地溪流中的人工基质上研究了硅藻组合的定殖模式。对两个地点中每一个的集合的密度、多样性、定殖率、生态行会和细胞大小等级进行跟踪 1 周。此外，还比较了每个地点在玻璃上、天然表皮生物膜和水中生长的组合。在这两个地点，暴露 30 分钟后，玻璃基板上的硅藻已经开始定植。在污染较轻的地点，总硅藻密度较高，低姿态和活动种的比例较高，5级（>1500μm3）的硅藻数量较多。在污染较严重的地点，来自备受瞩目的公会和 3 级 (300–599μm3) 的物种占主导地位。生态特征（生态行会和大小等级）对于营养丰富的低地早期定植的描述不够敏感，但最大的细胞构成了第一批定居者。结果表明，在人工基质上发育的组合是沉积物中成分的良好代表。