Department of Water Protection Engineering, Faculty of Environmental Sciences, University of Warmia and Mazury in Olsztyn, Prawocheńskiego 1 Street, 10-957 Olsztyn, Poland E-mail:
Department of Satellite Geodesy and Navigation, Faculty of Geodesy and Land Management, University of Warmia and Mazury in Olsztyn, Heweliusza 5 Street, 10-724 Olsztyn, Poland.
Water Sci Technol. 2014;69(9):1834-45. doi: 10.2166/wst.2014.084.
We investigated changes in the spatial distribution of phosphorus (P) and nitrogen (N) in the deep, mesotrophic Lake Hańcza. The raw data collection, supported by global navigation satellite system (GNSS) positioning, was conducted on 79 sampling points. A geostatistical method (kriging) was applied in spatial interpolation. Despite the relatively small area of the lake (3.04 km(2)), compact shape (shore development index of 2.04) and low horizontal exchange of water (retention time 11.4 years), chemical gradients in the surface waters were found. The largest variation concerns the main biogenic element - phosphorus. The average value was 0.032 at the extreme values of 0.019 to 0.265 mg L(-1) (coefficient of variation 87%). Smaller differences are related to nitrogen compounds (0.452-1.424 mg L(-1) with an average value of 0.583 mg L(-1), the coefficient of variation 20%). The parts of the lake which are fed with tributaries are the richest in phosphorus. The water quality of the oligo-mesotrophic Lake Hańcza has been deteriorating in recent years. Our results indicate that inferences about trends in the evolution of examined lake trophic status should be based on an analysis of the data, taking into account the local variation in water chemistry.
我们研究了深营养型哈尼亚察湖（Hańcza Lake）中磷（P）和氮（N）的空间分布变化。在全球导航卫星系统（GNSS）定位的支持下，我们在 79 个采样点进行了原始数据采集。应用了地统计学方法（克里金插值法）进行空间插值。尽管该湖面积相对较小（3.04 平方公里），形状紧凑（岸线发展指数为 2.04），水平水交换量低（滞留时间为 11.4 年），但在表层水中发现了化学梯度。最大的变化涉及主要的生物成因元素 - 磷。平均值为 0.032，极值为 0.019 至 0.265 毫克/升（变异系数 87%）。与氮化合物相关的差异较小（0.452-1.424 毫克/升，平均值为 0.583 毫克/升，变异系数为 20%）。有支流注入的湖区富含磷。近年来，寡营养型哈尼亚察湖的水质一直在恶化。我们的结果表明，对于所研究的湖泊营养状况演变趋势的推断，应该基于数据分析，并考虑到水化学的局部变化。
