Center for Marine and Climate Research, Institute for Biogeochemistry and Marine Chemistry, Hamburg University, Martin-Luther-King-Platz 6, 20146, Hamburg, Germany.
Environ Monit Assess. 2011 Mar;174(1-4):361-88. doi: 10.1007/s10661-010-1463-y. Epub 2010 May 2.
Natural background concentrations of nutrients are needed for the assessments of eutrophication processes and their status. Natural background concentrations of total nitrogen (TN) and total phosphorus (TP) were modelled for the rivers discharging into the German Bight and the Rhine considering individual catchment sizes, freshwater flows and soil types. These data were validated by comparison with data from unpolluted rivers. The consistency of modelled and some compiled nutrient concentrations was confirmed by their area-specific load dependency on freshwater discharges. Pristine inorganic nutrient concentrations were deduced from modelled relations to TN and TP in unpolluted rivers. Pristine nutrient gradients between rivers and offshore waters were estimated by linear mixing until a salinity of 32, continued by hyperbolic fits towards recent mean offshore values (salinity 34.5-35). Based on these gradients and recent mean salinities, maps of pristine surface gradients were plotted for the whole German Bight. Variability was transferred from recent conditions as percentage of standard deviation. Reported historical nutrient data and concentrations from unpolluted rivers, coastal and offshore North Sea waters are discussed concerning their relations to natural background conditions.
为评估富营养化过程及其现状，需要了解营养物质的自然背景浓度。考虑到个别集水区的大小、淡水流量和土壤类型，对流入德国湾和莱茵河的河流中的总氮（TN）和总磷（TP）的自然背景浓度进行了建模。通过与未受污染河流的数据进行比较，对这些数据进行了验证。通过对特定区域淡水排放的依赖关系，对模型化和一些汇编的营养物浓度进行了一致性确认。从未受污染河流中与 TN 和 TP 的模型关系推导出了原始无机营养物浓度。通过线性混合，在盐度为 32 之前，根据河流和近海之间的原始营养梯度进行了估算，然后用双曲线拟合到最近的平均近海值（盐度 34.5-35）。基于这些梯度和最近的平均盐度，为整个德国湾绘制了原始表面梯度图。可变性作为标准偏差的百分比从最近的条件中转移。报告的历史营养数据以及未受污染的河流、沿海和近岸北海水域中的浓度，根据其与自然背景条件的关系进行了讨论。
