Institute of Soil Biology and Biogeochemistry, Biology Centre CAS, České Budějovice, Czech Republic; Faculty of Science, University of South Bohemia, České Budějovice 370 05. Czech Republic.
Institute of Soil Biology and Biogeochemistry, Biology Centre CAS, České Budějovice, Czech Republic.
Sci Total Environ. 2023 Feb 1;858(Pt 2):159988. doi: 10.1016/j.scitotenv.2022.159988. Epub 2022 Nov 8.
Organic matter (OM) quantity, quality, and nutrient dynamics within twelve shallow lakes in the Czech Republic were assessed in the context of catchment soil pH and iron (Fe) concentration. The catchments of the lakes were classified into two categories: (i) slightly acidic (soil pH = 5.1-6.3) with Fe-rich soils (H_Fe; Fe = 315-344 mg kg in Mehlich 3 extract); and (ii) neutral (soil pH = 6.8-7.6) with Fe-poor soils (L_Fe; Fe = 126-259 mg kg in Mehlich 3 extract). The quality of OM in the two lake types was characterized using a combination of spectroscopic techniques (UV-Vis, fluorescence, and Fourier Transform Infrared spectroscopy). We show that dissolved nutrient and dissolved organic carbon (DOC) concentrations, as well as the amount of aromatic and protein-like compounds in the water column and sediment porewater were significantly (p < 0.01) lower in the H_Fe lakes compared to the waterbodies located within L_Fe catchments. The FTIR analyses of the H_Fe sediments contained higher relative concentrations of aromatic compounds with hydroxyl-containing functional groups and carbohydrates, while more aliphatic and oxidised OM was found in the L_Fe lake sediments. These results suggest that the pH value of catchment soils and, particularly, their Fe content have profound geochemical effects on the mobility of OM and nutrients in the sediments of recipient waters. Because the OM-Fe association stabilises OM in sediments, waterbodies within L_Fe catchments are likely more vulnerable to increasing eutrophication and oxygen depletion compared to those in H_Fe catchments and this has important implications for water quality management, risk assessment, and predictions of aquatic ecosystem vulnerability under conditions of accelerating climate change.
在捷克共和国的 12 个浅层湖泊中，评估了集水区土壤 pH 值和铁（Fe）浓度背景下的有机物质（OM）数量、质量和养分动态。将湖泊的集水区分为两类：（i）略酸性（土壤 pH = 5.1-6.3），土壤富含铁（ Mehlich 3 提取物中的 Fe = 315-344mg/kg）；（ii）中性（土壤 pH = 6.8-7.6），土壤贫铁（ Mehlich 3 提取物中的 Fe = 126-259mg/kg）。利用光谱技术（UV-Vis、荧光和傅里叶变换红外光谱）组合对两种湖泊类型的 OM 质量进行了表征。我们表明，与位于 L_Fe 集水区内的水体相比，H_Fe 湖泊的水中和沉积物孔隙水中的溶解养分和溶解有机碳（DOC）浓度以及芳香族和蛋白样化合物的含量明显（p < 0.01）较低。H_Fe 沉积物的 FTIR 分析含有相对较高浓度的含羟基官能团和碳水化合物的芳香族化合物，而 L_Fe 湖泊沉积物中则发现更多的脂肪族和氧化的 OM。这些结果表明，集水区土壤的 pH 值，特别是其 Fe 含量，对接收水体沉积物中 OM 和养分的流动性具有深远的地球化学影响。由于 OM-Fe 结合物稳定了沉积物中的 OM，因此与 H_Fe 集水区相比，L_Fe 集水区内的水体更易受到富营养化和缺氧增加的影响，这对水质管理、风险评估和预测水生生态系统在加速气候变化条件下的脆弱性具有重要意义。
