Waterborne Environmental, Inc., 2001 South First Street, Suite 109, Champaign, IL 61820, USA.
Sci Total Environ. 2013 Aug 1;458-460:125-39. doi: 10.1016/j.scitotenv.2013.03.070. Epub 2013 May 2.
Numerous studies characterizing the potential effects of atrazine on algal assemblages have been conducted using micro- or mesocosms; however, few evaluations focused on in situ lotic algal communities, potentially confounding risk assessment conclusions. This exploratory study, conducted at several sites in the midwestern United States where atrazine is commonly used, presents in situ observations of native algal communities relative to atrazine exposure and other parameters. Planktonic and periphytic algae from three streams in three Midwestern states, having historically differing atrazine levels, were sampled over a 16-week period in 2011 encompassing atrazine applications and the summer algal growth period at each site. Changes in abundance, diversity, and composition of algal communities were placed in the context of hydrological, climatic, and water quality parameters (including components sometimes present in agricultural runoff) also collected during the study. Diatoms dominated communities at each of the three sites and periphyton was much more abundant than phytoplankton. As expected, significant variations in algal community and environmental parameters were observed between sites. However, correspondence analysis plots revealed that patterns of temporal variation in algal communities at each site and in periphyton or phytoplankton were dominated by seasonal environmental gradients. Significant concordance in these seasonal patterns was detected among sites and between phytoplankton and periphyton communities (via procrustes Protest analysis), suggesting synchronicity of algal communities across a regional scale. While atrazine concentrations generally exhibited seasonal trends at the study watersheds; no effects on algal abundance, diversity or assemblage structure were observed as a result of atrazine pulses. This lack of response may be due to exposure events of insufficient concentration or duration (consistent with previously reported results) or the composition of the algal assemblages present. This was in contrast to the effects of elevated flow events, which were associated with significant changes in periphyton abundance, diversity and assemblage.
大量研究使用微宇宙或中宇宙来描述莠去津对藻类组合的潜在影响；然而，很少有评估集中在原位流水藻类群落，这可能会混淆风险评估结论。本探索性研究在美国中西部几个莠去津常用的地点进行，展示了与莠去津暴露和其他参数相关的原位自然藻类群落的观察结果。2011 年，在涵盖每个地点莠去津应用和夏季藻类生长期的 16 周内，从美国中西部三个州的三条溪流中采集了浮游和周丛藻类，这些溪流在历史上具有不同的莠去津水平。在研究期间还收集了藻类群落丰度、多样性和组成变化的水文、气候和水质参数（包括农业径流中有时存在的成分）。在三个地点中的每一个地点，硅藻都主导着群落，周丛生物比浮游生物更丰富。正如预期的那样，在各个地点之间观察到藻类群落和环境参数的显著变化。然而，对应分析图表明，每个地点藻类群落的时间变化模式以及周丛或浮游生物的季节性环境梯度为主导。在这些季节性模式中，在各个地点之间以及在浮游生物和周丛生物群落之间检测到显著的一致性（通过普罗克斯特分析），这表明在区域尺度上藻类群落具有同步性。虽然莠去津浓度在研究流域通常表现出季节性趋势；但由于莠去津脉冲，没有观察到对藻类丰度、多样性或组合结构的影响。这种无反应可能是由于暴露事件的浓度或持续时间不足（与先前报道的结果一致）或存在的藻类组合的组成。这与升高的水流事件的影响形成对比，这些事件与周丛生物丰度、多样性和组合的显著变化有关。
