Acceptable nutrient concentrations in agriculturally dominant landscapes: A comparison of nutrient criteria approaches for Nebraska rivers and streams
Acceptable nutrient concentrations in agriculturally dominant landscapes: A comparison of nutrient criteria approaches for Nebraska rivers and streams
复制标题
DOI：
10.1016/j.ecolind.2014.04.037
复制
发表时间：
2014-10
影响因子：
6.9
通讯作者：
T. Heatherly
中科院分区：
文献类型：
--
作者：
T. Heatherly
由于不确定的背景浓度和对水质的不确定影响，制定溪流的数值营养标准非常复杂。在本研究中，我实证检验了美国内布拉斯加州河流和溪流的总氮（TN）和总磷（TP）标准的多重标准的效用，使用：(1)整体人口营养百分位数；(2)参考流百分位数；(3)基于养分与人为土地利用关系的模型预测值；(4)营养物、无脊椎动物和鱼类组合的应激反应模型。我预测，内布拉斯加州制定的标准将高于美国环境保护署为相关营养生态区推荐的标准，因为新标准将只从这个以农业为主的州的河流中得出。此外，我预测基于生物群反应的标准将高于基于营养数据频率分布的标准，因为生物群已经被它们承受更高营养浓度的能力过滤了。种植作物占土地利用的绝大部分，全氮和全磷可以通过种植作物来预测。营养生态区在内布拉斯加州似乎并不是特别有用。EPA对总磷的建议低于我们制定的任何新标准（从113到599 μg/l），对总氮的建议几乎总是低于新标准（从552到2352 μg/l）。营养物质与生物完整性的关系较弱或不存在；TN在无脊椎动物和鱼类指标的3个预测指标中均不名列最佳，TP仅能很好地预测鱼类的污染耐受性，且该指标远高于EPA推荐值（599 μg/l）和基于百分位数和土地利用的标准。我讨论了内布拉斯加州农业密集溪流标准的适用性。
Developing numeric nutrient criteria for streams has been exceedingly complex due to uncertain background concentrations and uncertain impacts to water quality. In this study, I empirically examine the utility of multiple criteria for total nitrogen (TN) and total phosphorus (TP) criteria for rivers and streams of Nebraska, USA using: (1) whole-population nutrient percentiles; (2) reference stream percentiles; (3) model predicted estimates from relationships between nutrients and anthropogenic land usage; and (4) stressor–response modeling of nutrients and invertebrate and fish assemblages. I predicted that criteria developed for Nebraska would be greater than the criteria recommended by the US Environmental Protection Agency for the associated nutrient ecoregions because the new criteria would be derived from streams only within this agriculturally-dominated state. Also, I predicted that criteria based on responses of biota would be higher than those based on the frequency distribution of nutrient data because biota have been filtered by their ability to endure higher nutrient concentrations. The percentage of rowcrop agriculture was responsible for the vast majority of land usage, and TN and TP were predictable by rowcrop. Nutrient ecoregions did not appear to be particularly useful in Nebraska. EPA recommendations for TP were lower than any of the new criteria we developed (from 113 to 599 μg/l) and those for TN were almost always lower than new criteria (from 552 to 2352 μg/l). Relationships of nutrients to biotic integrity were weak or non-existent; TN was not among the best three predictors of invertebrate or fish metrics and TP was only a good predictor of the pollution tolerance of fish, and this criterion was much higher than EPA recommendations (599 μg/l) and criteria based on percentiles and land usage. I discuss the applicability of criteria to agriculturally-intense streams in Nebraska.