Diatoms have been widely used in stream health assessments as they are highly sensitive to water quality. There is no standardised method for diatom-based stream health assessments causing many substrates, both natural and artificial, to be used. Few studies have investigated the impact of substrate type on diatom assemblages in streams with highly variable water levels. To determine if the substrate type affects these assessments, diatoms were analysed from an artificial substrate (rope), rock and mud, from 17 sites in the Mount Lofty Ranges, South Australia. Rope has been advocated as a substrate as it mimics aquatic plants, while having advantages of artificial substrates (e.g. standardised habitat). We found that substrate type did not affect the stream health assessment based on the Diatom Species Index for Australian Rivers and hence the additional cost of deploying ropes in such studies is unlikely to be warranted. However, substrate type influenced diatom–nutrient relationships, with no relationship between nutrients in the stream water and diatoms in the mud substrate—possibly due to the nutrient subsidy provided by mud. Therefore, by contrast, the absence of nutrients provided by the rope substrate indicates it is suited to studies of nutrient status and sensitivity in streams.

中文翻译：

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底物类型对南澳大利亚洛夫蒂山脉基于硅藻的水质评估的影响

硅藻对水质高度敏感，因此已广泛用于河流健康评估。没有用于基于硅藻的河流健康评估的标准化方法，因此需要使用许多天然和人工基质。很少有研究调查底物类型对水位高度变化的溪流中硅藻组合的影响。为了确定基质类型是否影响这些评估，我们对来自南澳大利亚洛夫蒂山脉 17 个地点的人工基质（绳索）、岩石和泥土中的硅藻进行了分析。绳索被提倡作为基质，因为它模仿水生植物，同时具有人工基质（例如标准化栖息地）的优点。我们发现基质类型不会影响基于澳大利亚河流硅藻物种指数的河流健康评估，因此不太可能需要在此类研究中部署绳索的额外成本。然而，底物类型影响了硅藻-养分的关系，河流水中的养分与泥底中的硅藻之间没有关系——可能是由于泥浆提供的养分补贴。因此，相比之下，绳索基质不提供养分表明它适合研究溪流中的养分状况和敏感性。河流水中的养分与泥底中的硅藻之间没有关系——可能是由于泥提供的养分补贴。因此，相比之下，绳索基质不提供养分表明它适合研究溪流中的养分状况和敏感性。河流水中的养分与泥底中的硅藻之间没有关系——可能是由于泥提供的养分补贴。因此，相比之下，绳索基质不提供养分表明它适合研究溪流中的养分状况和敏感性。