PDF(Sci-hub)
Abstract：
Due to the lack of outlets, inflowing pollutants are often deposited in an endorheic lake, posing potential pressure on the environment. With climate change, extreme weather is expected to be more frequent and will contribute to the release of carbon and nutrients buried in the lakebeds. However, the distribution of sedimentary organic carbon and nutrients and the mechanisms that control the distribution are not fully understood, despite their significance to environmental development in endorheic lakes being widely recognized. In this study, the mechanisms controlling the sedimentary organic carbon and nutrient distributions in endorheic lakes were examined based on the analysis of an endorheic lake in the semiarid area of the Mongolian Plateau. The field survey results indicate that the concentrations of sedimentary organic carbon (TOC) and nutrients (NH3-N and TP) on the lakebed have significant correlations and present spatial heterogeneities. To further study the distribution mechanisms, numerical models were established to calculate the age of the water discharged from the rivers around the lake, and satellite remote sensing data were applied to examine the external source of organic carbon and nutrients and the factors influencing their movements to the lake. Based on the distribution of the water age, the water flow and mass transport trends in Lake Hulun were determined, and the time scales of the environmental processes were compared with those of water circulation. Further analysis indicates that the water circulation in the lake favors the accumulation of sedimentary organic carbon and nutrients in the northwestern part of the lake, and the organic carbon produced in the lake is transported to this region within an ice-free period. Satellite remote sensing data indicate that the region on the northwest bank of the lake experiences a larger terrestrial slope and better vegetation coverage than that on the southeast bank, which corresponds to a higher concentration of sedimentary organic carbon and nutrients in the northwest of the lake. This suggests that the sediment quality is closely related to the environment around the endorheic lake, and the larger slope and better vegetation coverage are significant factors for the high concentration of sedimentary organic carbon and nutrients on the lakebed under the conditions of scarce precipitation and low temperature. This study provides a theoretical basis and direction for further protection and management of the ecological environment of endorheic lakes.
摘要：
由于缺乏渠道，流入的污染物通常沉积在内河湖中，对环境造成潜在压力。随着气候变化,预计极端天气将更加频繁，并将有助于释放埋在湖床中的碳和营养物质。然而,沉积有机碳和养分的分布以及控制分布的机制尚未完全了解，尽管它们对内河湖的环境发展具有重要意义，但已得到广泛认可。在这项研究中,根据对蒙古高原半干旱地区内生湖的分析，研究了内生湖中沉积有机碳和养分分布的控制机制。野外调查结果表明，湖床上沉积有机碳（TOC）和养分（NH3-N和TP）的浓度具有显着相关性，并存在空间异质性。进一步研究分配机制,建立了数值模型来计算从湖泊周围河流排放的水的年龄，和卫星遥感数据被用来检查有机碳和养分的外部来源以及影响它们向湖泊移动的因素。根据水年龄的分布，确定了呼伦湖的水流和质量运输趋势，并将环境过程的时间尺度与水循环的时间尺度进行了比较。进一步分析表明，湖中的水循环有利于湖泊西北部沉积有机碳和养分的积累，湖中产生的有机碳在无冰期内被输送到该地区。卫星遥感数据表明，与东南岸相比，湖西北岸的区域经历了更大的陆地坡度和更好的植被覆盖率，这对应于湖西北部较高的沉积有机碳和养分浓度。这表明沉积物质量与内河湖周围的环境密切相关，在降水稀少和低温条件下，较大的坡度和较好的植被覆盖度是湖床沉积有机碳和养分浓度较高的重要因素。本研究为进一步保护和治理内河湖生态环境提供了理论依据和方向。
