Effects of major ions on natural benthic communities: an experimental assessment of the US Environmental Protection Agency aquatic life benchmark for conductivity
Effects of major ions on natural benthic communities: an experimental assessment of the US Environmental Protection Agency aquatic life benchmark for conductivity
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DOI：
10.1086/685085
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发表时间：
2016-03-01
影响因子：
1.8
通讯作者：
Kotalik, Chris
中科院分区：
文献类型：
--
作者：
Clements, William H.;Kotalik, Chris
淡水生态系统中HCO3-、Cl-、SO42-、Mg2+、Na+和Ca2+浓度的升高通常与人为干扰有关。美国环境保护署为受山顶采矿作业影响的溪流制定了一个基于现场的比电导（SC）基准，为300 μ S/cm。由于混杂变量的潜在影响以及难以证明SC升高与大型无脊椎动物反应之间的因果关系，该基准受到了批评。通过4个中观实验，量化了主要离子对水生昆虫群落的影响。我们将低（60-72 S/cm）和中等（200-250亩S/cm） SC溪流中的昆虫暴露在300亩S/cm左右的主要离子中。我们测量了群落代谢、大型无脊椎动物漂移、群落组成和存活率。在4个中环境实验中，66个分类群暴露于NaHCO3、MgSO4和NaCl环境中，8个优势科/亚科的密度足以形成sc -响应关系。每种主要离子的sc反应关系都很显著。随着SC的增加，漂移增加，群落代谢减少，其中蜉蝣目高度敏感，而毛翅目和双翅目相对耐受。EC20值（导致与对照组差异20%的SC）范围为151至3615 μ S/cm，大多数终点的EC20值为100至300 μ S/cm。在或附近的SC水平下，可能蝇的漂移、可能蝇和七倍蝇的丰度、可能蝇总丰度和群落代谢受到影响
Elevated concentrations of HCO3-, Cl-, SO42-, Mg2+, Na+, and Ca2+ in freshwater ecosystems are often associated with anthropogenic disturbances. The US Environmental Protection Agency developed a field-based specific conductance (SC) benchmark of 300 mu S/cm for streams affected by mountain-top mining operations. The benchmark has been criticized because of the potential influence of confounding variables and difficulty in demonstrating a causal relationship between elevated SC and macroinvertebrate responses. We conducted 4 stream mesocosm experiments to quantify the effects of major ions on aquatic insect assemblages. We exposed insects from streams with low (60-72 S/cm) and moderate (200-250 mu S/cm) SC to major ions at values bracketing 300 mu S/cm. We measured community metabolism, macroinvertebrate drift, community composition, and survival. Sixty-six taxa were exposed to NaHCO3, MgSO4, and NaCl in 4 mesocosm experiments, and 8 dominant families/subfamilies occurred in sufficient densities to develop SC-response relationships. Significant SC-response relationships occurred for each major ion tested. Drift increased and community metabolism decreased with increasing SC. Ephemeroptera were highly sensitive, whereas Trichoptera and Diptera were relatively tolerant. EC20 values (the SC that resulted in a 20% difference from controls) ranged from 151 to 3615 mu S/cm and were >300 mu S/cm for most endpoints. Mayfly drift, abundance of baetid and heptageniid mayflies, total mayfly abundance, and community metabolism were affected at SC levels near or