Department of Biology, University of Waterloo, 200 University Avenue West, Waterloo, ON N2L 3G1, Canada.
Environ Monit Assess. 2013 Sep;185(9):7895-913. doi: 10.1007/s10661-013-3143-1. Epub 2013 Mar 15.
Assessments of stream condition using benthic algal communities have traditionally relied on taxonomy-based approaches to compare community structure at sites exposed to a stressor versus reference sites. Taxonomy-based methods are often effective, but they require high levels of training and are relatively time consuming and expensive. We examined the utility of assessing stream biological condition using algal pigments. We used gradient and control-impact study designs in 2008 and 2009 to compare the extent that algal pigments versus taxonomic descriptors of algal community structure varied along a 10.5-km stretch of the Flat River (South Nahanni River watershed, NWT, Canada) encompassing a gradient of nutrients and metals at sites upstream, adjacent to and downstream of a northern metals mine. We also calculated costs to quantify algal pigments relative to taxonomy-based methods. Multivariate analyses (ANOSIM tests, redundancy analysis) identified that pigment concentrations from benthic algal samples differed significantly (p < 0.05) between non-exposed and exposed river sites and were related to variations in water physico-chemical conditions. By contrast, community composition determined from taxonomy-based enumeration to the Order and Family levels did not differ significantly between non-exposed and exposed sites, and relations with water physico-chemical conditions were weaker and inconsistent between the study years. In-house costs to quantify algal pigments were lower than commercial rates to describe community structure using taxonomy. Thus, our data suggests that analysis of benthic algal pigments represents a viable and cost-effective bio-monitoring method for assessing anthropogenic effects on stream condition that merits further evaluation.
使用底栖藻类群落评估水流状况传统上依赖于基于分类学的方法，将受到胁迫的地点与参照地点的群落结构进行比较。基于分类学的方法通常很有效，但需要高水平的培训，而且相对耗时且昂贵。我们研究了使用藻类色素评估溪流生物状况的效用。我们在 2008 年和 2009 年使用梯度和对照影响设计，比较了藻类色素与藻类群落结构的分类描述符在沿加拿大西北地区南纳汉尼河流域（Flat River）的 10.5 公里长的河段上沿营养物质和金属梯度的位置，包括上游、毗邻和下游的一个北方金属矿，沿着这些位置的变化程度。我们还计算了相对于基于分类学的方法量化藻类色素的成本。多元分析（ANOSIM 检验，冗余分析）确定了底栖藻类样本中的色素浓度在未暴露和暴露的河流地点之间存在显著差异（p < 0.05），并且与水物理化学条件的变化有关。相比之下，基于分类学的计数确定的群落组成在未暴露和暴露的地点之间没有显著差异，并且与水物理化学条件的关系在研究年份之间较弱且不一致。量化藻类色素的内部成本低于使用分类学描述群落结构的商业费率。因此，我们的数据表明，底栖藻类色素分析代表了一种可行且具有成本效益的生物监测方法，可用于评估人为因素对溪流状况的影响，值得进一步评估。
