Neal Colin, Hilton John, Wade Andrew J, Neal Margaret, Wickham Heather
Centre for Ecology and Hydrology Wallingford, Maclean Building, Crowmarsh Gifford, Wallingford, OXON, OX10 8BB, UK.
Sci Total Environ. 2006 Jul 15;365(1-3):84-104. doi: 10.1016/j.scitotenv.2006.02.039. Epub 2006 Apr 19.
Chlorophyll-a concentration variations are described for two major river basins in England, the Humber and the Thames and related to catchment characteristics and nutrient concentrations across a range of rural, agricultural and urban/industrial settings. For all the rivers there are strong seasonal variations, with concentrations peaking in the spring and summer time when biological activity is at its highest. However, there are large variations in the magnitude of the seasonal effects across the rivers. For the spring-summer low-flow periods, average concentrations of chlorophyll-a correlate with soluble reactive phosphorus (SRP). Chlorophyll-a is also correlated with particulate nitrogen (PN), organic carbon (POC) and suspended sediments. However, the strongest relationships are with catchment area and flow, where two straight line relationships are observed. The results indicate the importance of residence times for determining planktonic growth within the rivers. This is also indicated by the lack of chlorophyll-a response to lowering of SRP concentrations in several of the rivers in the area due to phosphorus stripping of effluents at major sewage treatment works. A key control on chlorophyll-a concentration may be the input of canal and reservoir waters during the growing period: this too relates to issues of residence times. However, there may well be a complex series of factors influencing residence time across the catchments due to features such as inhomogeneous flow within the catchments, a fractal distribution of stream channels that leads to a distribution of residence times and differences in planktonic inoculation sources. Industrial pollution on the Aire and Calder seems to have affected the relationship of chlorophyll-a with PN and POC. The results are discussed in relation to the Water Framework Directive.
本文描述了英格兰两个主要流域——亨伯河和泰晤士河的叶绿素a浓度变化情况，并将其与一系列农村、农业和城市/工业环境下的集水区特征及养分浓度相关联。所有河流的叶绿素a浓度都有强烈的季节性变化，在生物活性最高的春季和夏季达到峰值。然而，不同河流的季节性影响幅度差异很大。在春夏季低流量期，叶绿素a的平均浓度与可溶性活性磷（SRP）相关。叶绿素a还与颗粒态氮（PN）、有机碳（POC）和悬浮沉积物相关。不过，最强的关系存在于集水区面积和流量之间，呈现出两条直线关系。结果表明停留时间对于确定河流浮游生物生长的重要性。该地区一些河流因主要污水处理厂对废水进行磷去除，导致SRP浓度降低，但叶绿素a却没有相应变化，这也说明了停留时间的重要性。对叶绿素a浓度的一个关键控制因素可能是生长期间运河和水库水的输入：这同样与停留时间问题相关。然而，由于集水区内水流不均匀、河道呈分形分布导致停留时间分布不同以及浮游生物接种源存在差异等特征，可能存在一系列复杂因素影响集水区的停留时间。艾尔河和卡尔德河上的工业污染似乎影响了叶绿素a与PN和POC之间的关系。本文结合《水框架指令》对研究结果进行了讨论。
