Ottawa-Carleton Institute of Biology, 30 Marie Curie, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada.
Ottawa-Carleton Institute of Biology, 30 Marie Curie, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada; Science and Technology Branch, Environment Canada, 1125 Colonel By Drive, Raven Road, Carleton University, Ottawa, Ontario K1A 0H3, Canada.
Sci Total Environ. 2015 May 15;515-516:70-82. doi: 10.1016/j.scitotenv.2015.01.023. Epub 2015 Feb 18.
Agrochemicals, including fertilizers and herbicides, are significant contributors of non-point source pollution to surface waters and have the potential to negatively affect periphyton. We characterized periphyton communities using pigment markers to assess the effects of nutrient enrichment and the herbicide atrazine with in situ experimental manipulations and by examining changes in community structure along existing agrochemical gradients. In 2008, the addition of nutrients (20 mg/L nitrate and 1.25 mg/L reactive phosphate), atrazine (20 μg/L) and a combination of both nutrients and atrazine had no significant effect on periphyton biomass or community structure in a stream periphytometer experiment. In 2009, similar experiments with higher concentrations of atrazine (200 μg/L) at two stream sites led to some minor effects. In contrast, at the watershed scale (2010) periphyton biomass (mg/m(2) chlorophyll a) increased significantly along correlated gradients of nitrate and atrazine but no direct effects of reactive phosphate were observed. Across the watershed, the average periphyton community was composed of Bacillariophyceae (60.9%), Chlorophyceae (28.1%), Cryptophyceae (6.9%) and Euglenophyceae (4.1%), with the Bacillariophyceae associated with high turbidity and the Chlorophyceae with nitrate enrichment. Overall, effects of nitrate on periphyton biomass and community structure superseded effects of reactive phosphate and atrazine.
农用化学品，包括肥料和除草剂，是造成地表水污染的重要非点源污染源，并且有可能对周丛生物产生负面影响。我们使用色素标记物来描述周丛生物群落，以评估养分富化和除草剂莠去津的影响，采用原位实验操作和沿着现有农用化学品梯度的群落结构变化来进行研究。2008 年，在溪流周丛生物器实验中，添加养分（20mg/L 硝酸盐和 1.25mg/L 活性磷酸盐）、莠去津（20μg/L）以及养分和莠去津的组合对周丛生物生物量或群落结构没有显著影响。2009 年，在两个溪流地点进行了类似的、莠去津浓度更高（200μg/L）的实验，导致了一些较小的影响。相比之下，在流域尺度（2010 年），随着硝酸盐和莠去津相关梯度的增加，周丛生物生物量（mg/m(2)叶绿素 a）显著增加，但没有观察到活性磷酸盐的直接影响。在整个流域范围内，周丛生物群落平均由硅藻（60.9%）、绿藻（28.1%）、裸藻（6.9%）和眼虫（4.1%）组成，其中硅藻与高浊度有关，绿藻与硝酸盐富化有关。总体而言，硝酸盐对周丛生物生物量和群落结构的影响超过了活性磷酸盐和莠去津的影响。
