Eutrophication of streams and rivers: dissolved nutrient-chlorophyll relationships for benthic algae
Eutrophication of streams and rivers: dissolved nutrient-chlorophyll relationships for benthic algae
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DOI：
10.2307/1468279
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发表时间：
2000-03-01
影响因子：
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通讯作者：
Biggs, BJF
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文献类型：
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作者：
Biggs, BJF
用于预测富营养化对藻类生物量影响的统计模型，在水体系统中要比在水体系统中发展得更好，部分原因是受洪水控制的河流的动态物理性质。我分析了25条径流补给溪流和河流的30个站点的数据，建立了每月平均叶绿素a和最大叶绿素a作为可溶性养分浓度和累积天数（反映洪水干扰事件的频率）的函数的统计模型。各站间月平均叶绿素a变化的12-22.6%和最大叶绿素a变化的29.5-32.5%由水体养分的变化来解释。累积日数对月平均叶绿素a和最大叶绿素a变化的贡献率分别为39.7%和61.8%。结合溶解养分数据和累积天数的多元回归模型解释了站点间月平均叶绿素a变化的43.7 ~ 48.8%和最大叶绿素a变化的72.1 ~ 74.1%。在不经常发生洪水和积累期较长的河流中（例如100 - 100天），溶解营养物相对较小的增加大大增加了高生物量事件的频率。然而，正如可以预料的那样，这一结果并没有发生在更容易发生洪水的河流中。基于最大叶绿素A的回归模型，提出了一种以营养浓度和累积天数为函数来预测低、中、富营养化条件的nomograph。该模型需要进一步测试，但可能有助于预测其他温带溪流和河流中营养物质变化对底栖藻类生物量的影响。我建议，可以根据当地洪水频率和可用于生物量积累的预期时间制度，在溪流中设置防止底栖藻类增殖的可变营养标准。本分析表明，管理营养物供应不仅可以减少最大生物量的大小，而且可以减少底栖藻类在溪流中增殖的频率和持续时间。
Statistical models for predicting the effects on algal biomass of eutrophication are much better developed for lentic systems than for lotic systems, partly because of the dynamic physical nature of streams as controlled by flood regimes. I analyzed data from 30 sites in 25 runoff-fed streams and rivers to develop statistical models for mean monthly and maximum chlorophyll a as a function of soluble nutrient concentrations and days of accrual (reflecting the frequency of flood disturbance events). Variation in stream-water nutrients explained 12-22.6% of the variation in mean monthly chlorophyll a and 29.5-32.5% of the variation in maximum chlorophyll a among sites. Days of accrual explained 39.7% and 61.8 % of the variation in mean monthly and maximum chlorophyll a, respectively. Multiple regression models combining dissolved nutrient data and days of accrual explained 43.7-48.8% of the variation in mean monthly chlorophyll a and 72.1-74.1% of the variation in maximum chlorophyll a among sites. In streams with infrequent floods and long accrual periods (e.g., >100 d), a relatively small increase in dissolved nutrients greatly increased the frequency of high biomass events. However as could be anticipated, this result did not occur in more flood-prone streams. A nomograph to predict oligo-, meso-, and eutrophic conditions as a function of nutrient concentrations and days of accrual is presented based on the regression models for maximum chlorophyll a. The models need further testing, but might be useful for predicting the effects of changes in nutrients on benthic algal biomass in other temperate streams and rivers. I suggest that variable nutrient criteria for the prevention of benthic algal proliferations could be set in streams in relation to regimes of local flood frequency and expected time available for biomass accrual. The present analysis suggests that managing nutrient supply could not only reduce the magnitude of maximum biomass, but also reduce the frequency and duration of benthic algal proliferations in streams.