Influence of climate, geology and humans on spatial and temporal nutrient geochemistry in the subtropical Richmond River catchment, Australia
Influence of climate, geology and humans on spatial and temporal nutrient geochemistry in the subtropical Richmond River catchment, Australia
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DOI：
10.1071/mf99025
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发表时间：
2001-03
影响因子：
1.8
通讯作者：
L. McKee;B. Eyre;S. Hossain;Peter R Pepperell
中科院分区：
文献类型：
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作者：
L. McKee;B. Eyre;S. Hossain;Peter R Pepperell
两年来，我们对亚热带里士满河流域的水质进行了时空监测。养分浓度以复杂的方式随季节变化，最高浓度（最大值 = 3110 µg N L – 1 和 572 µg P L –1 ）与洪水相关。然而，与世界其他地区相比，中位浓度（444 µg N L – 1 和 55 µg P L – 1 ）浓度相对较低。溪流中氮和磷的形态随季节变化，雨季无机氮和磷的比例较高。泄洪后 2-3 个月发现最低养分浓度。随着旱季的到来，浓度增加归因于点源和河流流量减少。地质与水质和养分浓度之间存在统计学上显着的关系，下游增加，并且与人口密度和奶牛养殖显着相关。尽管流域部分地区的地质情况不同，土壤和岩石中的磷含量自然较高，但人为影响对里士满河流域的水质影响最大。降雨质量似乎也与人类活动在空间和季节上相关。尽管亚热带里士满河流域对土地利用变化的响应与北美和欧洲的温带系统相似，但季节模式似乎更为复杂，并且可能是典型的以农业用地为主的亚热带流域。
Water quality was monitored on a spatial and temporal basis in the subtropical Richmond River catchment over two years. Nutrient concentrations varied seasonally in a complex manner with highest concentrations (maximum =3110 µg N L – 1 and 572 µg P L –1 ) associated with floods. However, median (444 µg N L – 1 and 55 µg P L – 1 ) concentrations were relatively low compared with other parts of the world. The forms of nitrogen and phosphorus in streams varied seasonally, with greater proportions of inorganic nitrogen and phosphorus during the wet season. Minimum nutrient concentrations were found 2—3 months after flood discharge. With the onset of the dry season, concentration increases were attributed to point sources and low river discharge. There were statistically significant relationships between geology and water quality and nutrient concentrations increased downstream and were significantly related to population density and dairy farming. In spite of varying geology and naturally higher phosphorus in soils and rocks in parts of the catchment, anthropogenic impacts had the greatest effects on water quality in the Richmond River catchment. Rainfall quality also appeared to be related both spatially and seasonally to human activity. Although the responses of the subtropical Richmond River catchment to changes in land use are similar to those of temperate systems of North America and Europe, the seasonal patterns appear to be more complex and perhaps typical of subtropical catchments dominated by agricultural land use.