概括
实验性湖泊酸化到pH值5.0揭示了关键的食物网中断. 关键物种在pH值5.8时消失,这表明不可逆转的生态系统损害比以前认为的更早发生.
科学领域:
- 环境科学 环境科学
- 生态生态学 生态生态学
- 水生生态系统 水生生态系统
背景情况:
- 酸沉积对水生生态系统产生影响.
- 之前的研究依赖于综合调查.
- 关于长期酸化效应的实验数据有限.
研究的目的:
- 通过实验确定长期湖泊酸化对水生食物网的影响.
- 将实验结果与综合调查的预测进行比较.
- 为了确定关键水生生物的关键pH值值.
主要方法:
- 在一个小湖 (湖223) 经过8年的实验性酸化,将pH值从6.8降至5.0.
- 监测植物浮游生物,动物浮游生物,盆地甲类动物和鱼类种群的变化.
- 评估初级生产,分解速度和营养度.
主要成果:
- 植物浮游生物物种组成的显著变化.
- 鱼类的繁殖停止和盆地甲类的消失.
- 在沿海地区出现丝状藻类.
- 在pH值5.8下消除关键的食物网生物 (Mysis relicta,Pimephales promelas).
- 初级产量,分解或营养度没有下降,这与全视调查预测相反.
- 在pH值低于5.4.4的情况下,没有鱼类繁殖.
结论:
- 无法逆转的水生生态系统压力在酸化过程中比以前认为的更早地发生.
- 离子度,而不是毒性,是观察到变化的主要原因.
- 湖泊酸化导致了严重的食物网干扰和潜在的无鱼状况.
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