Aquascience Consultancy Limited, Chesterfield, Derbyshire, S42 7JS, UK.
School of Geography, University of Nottingham, NG7 2RD, UK.
Environ Pollut. 2018 Jun;237:792-802. doi: 10.1016/j.envpol.2017.10.131. Epub 2017 Nov 15.
The ecological effects of interacting stressors within lotic ecosystems have been widely acknowledged. In particular, the ecological effects of elevated fine sediment inputs and phosphate have been identified as key factors influencing faunal community structure and composition. However, while knowledge regarding adult and larval life stage responses to environmental stressors has grown, there has been very limited research on their eggs. In this study, the eggs of the mayfly Serratella ignita (Ephemerellidae: Ephemeroptera) were collected and incubated in laboratory aquaria to hatching under differing concentrations of inert suspended sediment (SS) and orthophosphate (OP), individually and in combination. Results indicate that SS and OP have greater effects on egg hatching in combination than when either were considered in isolation. SS displayed a greater effect on egg survival than OP in isolation or when OP was added to elevated SS treatments. Egg mortality in control treatments was around 6% compared to 45% in treatments with 25 mg l SS and 52% in 0.3 mg l OP treatments. Even relatively modest levels of each stressor (10 mg l SS; 0.1 mg l OP), below national legal thresholds, had significant effects on egg survival to hatching. The results support calls for legal levels of SS to be reassessed and suggest that more research is required to assess the impacts of pollution on invertebrate egg development given their different sensitivity and exposure pathways compared to other life stages.
溪流生态系统中相互作用的胁迫因素的生态影响已得到广泛认可。特别是，已确定升高的细泥沙输入和磷酸盐对动物区系群落结构和组成的影响是关键因素。然而，尽管人们对成年和幼虫阶段对环境胁迫的反应的了解有所增加，但对其卵的研究却非常有限。在这项研究中，收集并在实验室水族箱中孵化蜉蝣 Serratella ignita（蜉蝣科：蜉蝣目）的卵，以在不同浓度的惰性悬浮泥沙（SS）和正磷酸盐（OP）下孵化，单独和组合。结果表明，SS 和 OP 组合对卵孵化的影响大于单独考虑时的影响。在单独或在升高的 SS 处理中添加 OP 时，SS 对卵存活率的影响大于 OP。对照处理中的卵死亡率约为 6％，而在 25mg l SS 处理中的死亡率为 45％，在 0.3mg l OP 处理中的死亡率为 52％。即使是每个胁迫因素（10mg l SS；0.1mg l OP）的相对适度的水平，低于国家法定阈值，对卵孵化的存活率也有显著影响。结果支持重新评估 SS 的法定水平的呼吁，并建议需要进行更多的研究，以评估污染对无脊椎动物卵发育的影响，因为与其他生命阶段相比，它们的敏感性和暴露途径不同。
