Wood Rebecca J, Mitrovic Simon M, Lim Richard P, Kefford Ben J
Freshwater and Estuarine Research Group, Ecosystem Security Team, School of Life Sciences, University of Technology Sydney, PO Box 123, Broadway, NSW 2000, Australia.
Freshwater and Estuarine Research Group, Ecosystem Security Team, School of Life Sciences, University of Technology Sydney, PO Box 123, Broadway, NSW 2000, Australia.
Aquat Toxicol. 2017 Aug;189:200-208. doi: 10.1016/j.aquatox.2017.06.013. Epub 2017 Jun 19.
Diffuse agricultural runoff into rivers can result in contamination with herbicides for prolonged periods of time. Chronic exposure to herbicides has the potential to alter toxic impacts in primary producers such as benthic diatoms. Determining how individual diatom taxa respond to herbicide exposure over varied exposure durations is essential for assessing herbicide impacts. This study investigated the responses of various benthic diatom taxa and effects at the community level over 12days of atrazine exposure. Diatom communities were collected from two sites with differing exposure histories; a relatively unpolluted site (Alligator Creek) and an agricultural stream (Barratta Creek) known to be polluted by atrazine and other herbicides. Diatom community composition and the proportion of healthy cells per taxon were assessed at 0, 2, 3, 6, 9 and 12days of atrazine exposure. Pollution history altered the response of the diatom community to atrazine exposure. In the Alligator Creek diatom community there was a shift in composition towards more tolerant taxa and the loss of sensitive taxa in atrazine exposed treatments. The sensitive taxon (Gomphonema truncatum) was consistently affected by atrazine toxicity. Conversely, the polluted Barratta Creek diatom community was not strongly affected by atrazine exposure. Our study shows that during chronic atrazine exposure some taxa demonstrated the ability to recover despite initial toxicity response. Recovery could be an important trait for understanding the ecological effect of herbicide exposure on diatom species in nature and in applied circumstances such as biomonitoring indices.
农业径流扩散到河流中会导致除草剂长期污染。长期接触除草剂有可能改变对初级生产者（如底栖硅藻）的毒性影响。确定不同的硅藻分类群在不同暴露持续时间下对除草剂暴露的反应，对于评估除草剂的影响至关重要。本研究调查了在12天的莠去津暴露期间，各种底栖硅藻分类群的反应以及群落水平上的影响。从两个具有不同暴露历史的地点采集硅藻群落；一个相对未受污染的地点（短吻鳄溪）和一条已知受莠去津和其他除草剂污染的农业溪流（巴拉塔溪）。在莠去津暴露的第0、2、3、6、9和12天评估硅藻群落组成和每个分类群中健康细胞的比例。污染历史改变了硅藻群落对莠去津暴露的反应。在短吻鳄溪硅藻群落中，暴露于莠去津的处理中，群落组成向更耐受的分类群转变，敏感分类群减少。敏感分类群（截头异极藻）一直受到莠去津毒性的影响。相反，受污染的巴拉塔溪硅藻群落对莠去津暴露的影响不强烈。我们的研究表明，在长期莠去津暴露期间，一些分类群尽管最初有毒性反应，但仍表现出恢复的能力。恢复可能是理解除草剂暴露对自然界和生物监测指标等应用环境中硅藻物种生态影响的一个重要特征。
