陈月^1,,
林琪²,
刘恩峰^1,,,
张恩楼²,
王萧¹,
沈吉³
1. 山东师范大学地理与环境学院, 山东 济南 250014
2. 中国科学院南京地理与湖泊研究所, 湖泊与环境国家重点实验室, 江苏 南京 210008
3. 南京大学地理与海洋科学学院, 江苏 南京 210023

基金项目: 国家自然科学基金项目(批准号：41672354)、第二次青藏高原综合科学考察研究项目(批准号：2019QZKK0202)和科技部基础性工作专项项目(批准号：2014FY110400)共同资助


详细信息

作者简介: 陈月, 女, 24岁, 硕士研究生, 自然地理学专业, E-mail: 2845223664@qq.com

通讯作者: 刘恩峰, E-mail: liuenfeng@sdnu.edu.cn

中图分类号: P592;P941.78

收稿日期:2020-12-30
修回日期:2021-04-23
刊出日期:2021-07-30

Spatio-temporal variations of sedimentary phosphorus in Lugu Lake and its environmental implications

CHEN Yue^1,,
LIN Qi²,
LIU Enfeng^1,,,
ZHANG Enlou²,
WANG Xiao¹,
SHEN Ji³
1. College of Geography and Environment, Shandong Normal University, Jinan 250014, Shandong
2. State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, Jiangsu
3. School of Geography and Ocean Sciences, Nanjing University, Nanjing 210023, Jiangsu


More Information

Corresponding author: LIU Enfeng,E-mail:liuenfeng@sdnu.edu.cn

MSC: P592;P941.78

--> Received Date: 30 December 2020
Revised Date: 23 April 2021
Publish Date: 30 July 2021


摘要
摘要:湖泊沉积物中磷累积特征反映了流域人类活动影响下的磷入湖通量的变化，与湖泊生态环境密切相关。本研究分析了泸沽湖15根长17~27cm沉积短岩芯中磷的含量，评估了自然源与人为源磷的贡献，探讨了近140年来不同来源磷累积的时空变化特征及其与流域人类活动和湖泊生态环境的关系。结果表明，不同湖区沉积物中磷含量垂向变化趋势总体一致。以南部湖心区LGS岩芯为例，1960年前，沉积物中磷的含量与累积通量较低，为人类活动干扰较弱的准自然沉积；1960~2000年，自然源与人为源磷的含量和累积通量均逐渐增加，其中1960~1980年和1980~2000年人为源磷累积通量平均分别为4.9mg/(m²·a)和39.1mg/(m²·a)。2000年以来，沉积物中自然源磷的累积通量略有降低，但人为源磷的累积通量持续升高，平均为109mg/(m²·a)。空间上，南部湖区自然和人为源磷的累积通量总体上高于北部湖区，不同时期自然源磷的累积通量高值区均位于南部湖区东部，而沿岸居民点密集分布的南北湖区连接处和西北部湖区人为源磷的累积通量相对较高。不同来源磷累积通量的时空变化主要与农业和旅游业发展导致的土壤侵蚀和污染排放输入有关。沉积物中磷累积通量与硅藻、摇蚊等水生生物属种呈同步的历史变化趋势，指示了磷输入对湖泊生态环境变化的重要影响。
关键词: 磷/
沉积物/
时空变化/
人类活动/
生态环境/
泸沽湖

Abstract:Phosphorus accumulation in lake sediment is closely related to the watershed human activities and is also an important factor regulating the lake eco-environment evolution. In this study, phosphorus contents in 15 short sediment cores collected from different lake areas of Lugu Lake(27°36'~27°47'N, 100°43'~100°54'E) were analyzed, which is a deep plateau lake in Southwest China. The chronology analysis of nearly 140 years was constructed in LGS core using the gamma dating method by measuring radionuclides(²¹⁰Pb, ²²⁶ Ra and ¹³⁷Cs). The detrital and anthropogenic contributions to phosphorus accumulation in the sediment over the past hundred years were quantitatively evaluated, and their relationships with human activities and lake ecological environment were discussed. Phosphorus contents in the 15 sediment profiles showed similar trends. The temporal variations of phosphorus accumulation were described in detail taking the core LGS in the center of southern lake area as an example. The contents and accumulation rates of total phosphorus were low before the 1960, with averages of 825mg/kg and 223mg/(m²·a). This period was corresponded to quasi-natural sedimentary environment under weak human disturbance in the watershed. From the 1960 to 2000, the contents and accumulation rates of total phosphorus increased gradually. The values were averaged 1115mg/kg and 562mg/(m²·a) during 1960~1980, and 2241mg/kg and 1086mg/(m²·a) during 1980~2000, respectively. The accumulation rates of anthropogenic phosphorus were averaged 4.9mg/(m²·a) and 39.1mg/(m²·a) during 1960~1980 and 1980~2000, respectively. The increases in accumulation rates of total phosphorus and anthropogenic phosphorus were mainly related to the intensified soil erosion with deforestation and agriculture development and wastewater discharge due to the development of agriculture and tourism. Since the 2000, the accumulation rates of total phosphorus reached the highest values over the past hundred years and was averaged 1086mg/(m²·a). In this period, the accumulation fluxes of detrital phosphorus decreased slightly due to the reduced soil erosion with the increase of vegetation coverage, but the values of anthropogenic phosphorus increased sharply most likely due to continued discharge of domestic sewage, with average of 109 mg/(m²·a). The temporal variations in accumulation rates of phosphorus were generally synchronized with the succession of aquatic organism such as diatoms and chironomids, indicating the potential driving effects of phosphorus input on the eco-environmental evolutions of Lugu Lake. Spatially, the accumulation rates of total, detrital and anthropogenic phosphorus were in the southern lake area were generally higher than those in the northern, with values of 495mg/(m²·a) and 259mg/(m²·a) during 1920~1985 and 1005mg/(m²·a) and 582mg/(m²·a) during 1985~2014 for total phosphorus in the southern and northern lake areas, respectively. The spatial patterns in accumulation rates of detrital phosphorus in the two periods of 1920~1985 and 1985~2014 were generally similar, and the high values were occurred in the eastern part of the southern lake region due to intensified soil erosion in the sub-basin and suspended particles retaining by aquatic plants. The accumulation rates of anthropogenic phosphorus were higher in the junction part of the north and south lake areas as well as the northwest lake area due to domestic sewage discharges where the coastal settlements are densely distributed.
Key words:phosphorus/
sediment/
temporal and spatial variations/
human activities/
ecological environment/
Lugu Lake



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