Department of River Ecology, Helmholtz-Centre for Environmental Research UFZ, Brückstraße 3a, 39114, Magdeburg, Germany,
Environ Monit Assess. 2013 Nov;185(11):9221-36. doi: 10.1007/s10661-013-3247-7. Epub 2013 Jun 19.
The Bode catchment (Germany) shows strong land use gradients from forested parts of the National Park (23% of total land cover) to agricultural (70%) and urbanised areas (7%). It is part of the Terrestrial Environmental Observatories of the German Helmholtz association. We performed a biogeochemical analysis of the entire river network. Surface water was sampled at 21 headwaters and at ten downstream sites, before (in early spring) and during the growing season (in late summer). Many parameters showed lower concentrations in headwaters than in downstream reaches, among them nutrients (ammonium, nitrate and phosphorus), dissolved copper and seston dry mass. Nitrate and phosphorus concentrations were positively related to the proportion of agricultural area within the catchment. Punctual anthropogenic loads affected some parameters such as chloride and arsenic. Chlorophyll a concentration and total phosphorus in surface waters were positively related. The concentration of dissolved organic carbon (DOC) was higher in summer than in spring, whereas the molecular size of DOC was lower in summer. The specific UV absorption at 254 nm, indicating the content of humic substances, was higher in headwaters than in downstream reaches and was positively related to the proportion of forest within the catchment. CO₂ oversaturation of the water was higher downstream compared with headwaters and was higher in summer than in spring. It was correlated negatively with oxygen saturation and positively with DOC concentration but negatively with DOC quality (molecular size and humic content). A principle component analysis clearly separated the effects of site (44%) and season (15%), demonstrating the strong effect of land use on biogeochemical parameters.
博德流域（德国）的土地利用存在明显梯度，从国家公园的森林部分（占总土地覆盖面积的 23%）到农业区（70%）和城市地区（7%）。它是德国亥姆霍兹联合会陆地环境观测站的一部分。我们对整个河网进行了生物地球化学分析。在春季早期和生长季节（夏末），在 21 个源头和 10 个下游地点采集了地表水样本。与下游相比，许多参数在源头的浓度较低，其中包括营养物（氨、硝酸盐和磷）、溶解铜和悬浮物干质量。硝酸盐和磷浓度与流域内农业区的比例呈正相关。突发性人为负荷会影响一些参数，如氯和砷。地表水的叶绿素 a 浓度和总磷呈正相关。夏季溶解有机碳（DOC）的浓度高于春季，而夏季 DOC 的分子量较小。254nm 处的特定紫外吸收值（SUVA254）表明腐殖质含量较高，源头的 SUVA254 值高于下游，且与流域内森林比例呈正相关。与源头相比，下游水中的 CO₂过饱和度较高，夏季高于春季。它与氧饱和度呈负相关，与 DOC 浓度呈正相关，但与 DOC 质量（分子量和腐殖质含量）呈负相关。主成分分析清楚地分离了地点（44%）和季节（15%）的影响，证明了土地利用对生物地球化学参数的强烈影响。
