Hydrological isolation accelerates algal blooms in floodplain lakes: Biomarker evidence from Dongting Lake, China and its satellite lake

IF 12.4 1区环境科学与生态学 Q1 ENGINEERING, ENVIRONMENTAL Water Research Pub Date : 2025-07-01 Epub Date: 2025-03-03 DOI:10.1016/j.watres.2025.123430

Linghan Zeng , Virginia N. Panizzo , Zekun Wang , Xianyu Huang , Xu Chen , Suzanne McGowan

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Abstract

Hydrological disconnection from main channels (either via natural siltation or due to construction of hydrological infrastructures) is modifying biogeochemical cycling in river-floodplain systems. Knowledge on how this process influences phytoplankton composition and harmful algal blooms (HABs) in floodplain lakes is quite scant due to the lack of long-term water quality monitoring and the concurrent influence of multiple drivers of change. Here, chlorophyll and carotenoid pigment biomarkers from dated sediment cores were analyzed from Dongting Lake (China's second largest freshwater lake) and one of its satellite lakes (Donghu) in the Yangtze floodplain, to evaluate the long-term influence of hydrological isolation on algal community composition and HABs. The results showed that pigment concentrations and the ratio of canthaxanthin/diatoxanthin (which reflects the relative abundance of cyanobacteria to diatoms) increased after the 1910s in Donghu Lake, when it was separated from Dongting Lake due to siltation. In contrast, significant increases in pigments started from the 1980s in Dongting Lake. Variance partitioning analysis revealed that the combined influence of hydrology, temperature and anthropogenic pollutants explained the largest proportion of variance (33.4%) in the pigment assemblages in Donghu Lake, followed by the joint effects of anthropogeny pollutants and hydrology (23.6%) and the sole effects of anthropogenic pollutants (14.9%) and hydrology (11.2%). In Dongting Lake, anthropogenic pollutants explained 24.5% of the variance in pigment assemblages solely, followed by the additive effects of anthropogenic pollutants and temperature (17.8%). These long-term analyses therefore demonstrate that, in combination with anthropogenic pollutants and warming, hydrological isolation from the main channel may stimulate algal production and the prevalence of cyanobacteria, whereas free hydrological connection with the Yangtze main channel seems to alleviate such HABs in these Yangtze floodplain lakes.

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水文隔离加速了河漫滩湖泊的藻华：来自洞庭湖及其卫星湖的生物标志物证据

主河道的水文断流（无论是由于自然淤积还是由于水文基础设施的建设）正在改变河流-漫滩系统的生物地球化学循环。由于缺乏长期的水质监测和多种变化驱动因素的同时影响，关于这一过程如何影响洪泛区湖泊浮游植物组成和有害藻华（HABs）的知识相当匮乏。本文利用长江漫滩洞庭湖（中国第二大淡水湖）及其卫星湖东湖沉积物岩心的叶绿素和类胡萝卜素生物标志物进行分析，以评估水文隔离对藻类群落组成和赤潮的长期影响。结果表明：20世纪10年代后，由于淤积与洞庭湖分离，东湖水体中色素浓度和反映蓝藻与硅藻相对丰度的角黄素/硅藻黄素比值有所增加；相比之下，洞庭湖色素的显著增加始于20世纪80年代。方差划分分析表明，水文、温度和人为污染物对东湖色素组合的影响最大（33.4%），其次是人为污染物和水文的共同影响（23.6%）和人为污染物和水文的单独影响（14.9%）（11.2%）。在洞庭湖，人为污染对色素组合变化的贡献率最大，占24.5%，其次是人为污染和温度的加性影响，占17.8%。因此，这些长期分析表明，在人为污染物和气候变暖的共同作用下，与长江主河道的水文隔离可能会刺激藻类的产生和蓝藻的流行，而与长江主河道的自由水文连接似乎会减轻这些长江洪泛平原湖泊的赤潮。

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来源期刊

Water Research 环境科学-工程：环境

CiteScore

20.80

自引率

9.40%

发文量

1307

审稿时长

38 days

期刊介绍： Water Research, along with its open access companion journal Water Research X, serves as a platform for publishing original research papers covering various aspects of the science and technology related to the anthropogenic water cycle, water quality, and its management worldwide. The audience targeted by the journal comprises biologists, chemical engineers, chemists, civil engineers, environmental engineers, limnologists, and microbiologists. The scope of the journal include: •Treatment processes for water and wastewaters (municipal, agricultural, industrial, and on-site treatment), including resource recovery and residuals management; •Urban hydrology including sewer systems, stormwater management, and green infrastructure; •Drinking water treatment and distribution; •Potable and non-potable water reuse; •Sanitation, public health, and risk assessment; •Anaerobic digestion, solid and hazardous waste management, including source characterization and the effects and control of leachates and gaseous emissions; •Contaminants (chemical, microbial, anthropogenic particles such as nanoparticles or microplastics) and related water quality sensing, monitoring, fate, and assessment; •Anthropogenic impacts on inland, tidal, coastal and urban waters, focusing on surface and ground waters, and point and non-point sources of pollution; •Environmental restoration, linked to surface water, groundwater and groundwater remediation; •Analysis of the interfaces between sediments and water, and between water and atmosphere, focusing specifically on anthropogenic impacts; •Mathematical modelling, systems analysis, machine learning, and beneficial use of big data related to the anthropogenic water cycle; •Socio-economic, policy, and regulations studies.