Community structure and ecological responses to hydrological changes in benthic algal assemblages in a regulated river: application of algal metrics and multivariate techniques in river management

Abstract

The flow regime of the Wimmera River was substantially modified due to the construction of a water supply reservoir. Samples of diatoms, soft algae and measurements of water quality were analysed at ten sampling sites for three years (between February 2012 and November 2014) along the MacKenzie River, a tributary of the Wimmera River, in different seasons and under different flow regimes, to understand the spatial and temporal variation in the relationship between algal communities, water quality and stream condition. Baseline information on algal communities and water quality was collected during base flow conditions, while experiments on the effect of water releases on algal communities were based on flow regime variations (manipulated flow regimes), specifically on the algae community structure, water quality and ecosystem function. Algal species composition changed along the river under different flow regimes and different seasons. Under base flow, Bacillariophyta (diatoms) were more abundant upstream and filamentous green algae were more abundant downstream.The results showed that the algal composition shifted downstream after water release events. Chlorophyta (Green algae), Cyanophyta (Blue-green algae) and Chrysophyta gradually increased from upstream to downstream under base flow conditions, and before water releases, whereas diatoms were greater upstream and increased downstream after water releases. The results suggest that by tailoring the discharge and duration of the river flows, through the amalgamation of consumptive and environmental flows would improve the condition of the stream, and supplementing the positive effects of the flows dedicated to improving environmental outcomes.

Impact of barrages on assemblage pattern of phytoplankton in tropical river Ganga, India

“…Several authors have also reported similar observations in the river Ganga and other aquatic systems (Dwivedi & Srivastava, 2017 ; Gogoi et al, 2019 ; Kumar et al, 2015a , b 2017 , 2020 ; Matta et al, 2018 ; Sharma et al, 2016 ; Vajravelu et al, 2018 ; Wassie & Melese, 2017 ). Bacillariophyta, Charophyta, and Chlorophyta were assembled ubiquitously and were suggested to be bearable to high flow and sustained in comparable clean water (Atazadeh et al, 2021 ). Bacillariophyta was the dominant group in the present study, and several researchers also reported similar remarks on the river Ganga, which is consistent with our findings (Khanna et al, 2012 ; Kumar et al, 2022a , b ; Shukla et al, 2015 ).…”

“…The low abundance and diversity of phytoplankton in the monsoon season in the current study might be due to the high flow of water current, and only well-adapted phytoplankton species ( Cyclotell sp., Navicula sp., Synedra sp.) showed their presence (Inyang & Wang, 2020 ; Atazadeh et al, 2021 ). High diversity in the post-monsoon season might occur due to high phosphate in water.…”

Monitoring of Rivers and Streams Conditions Using Biological Indices with Emphasis on Algae: A Comprehensive Descriptive Review toward River Management

“…Diatoms also play important roles in biotechnology, engineering, biology, and material science [321] but their main role in the general riverine environmental condition [29,322,323], water quality ecological assessment of aquatic systems [107,152,[324][325][326][327][328], eutrophication [78, 314,329], pollution [330,331], bioassessment [107,116,[332][333][334], and urbanization [335][336][337][338].…”

Using Algal Indices to Assess the Ecological Condition of the Aras River, Northwestern Iran

“…This is because it is essential to demonstrate the effect of pollutants on biota as the effect on water quality is also influenced by the nature of the receiving waters. Water in rivers can be classified, based on biology, hydrology, and quality, into different ecological categories of conditions such as bad, poor, moderate, good, or high [1][2][3]. Water pollution can be defined as the contamination of water bodies by the entrance of large amounts of materials/substances into those bodies, resulting in physical or chemical changes to the water, modifying the natural features of the water, degrading the water quality, and adversely affecting humans and the environment [1,2].…”

“…Water in rivers can be classified, based on biology, hydrology, and quality, into different ecological categories of conditions such as bad, poor, moderate, good, or high [1][2][3]. Water pollution can be defined as the contamination of water bodies by the entrance of large amounts of materials/substances into those bodies, resulting in physical or chemical changes to the water, modifying the natural features of the water, degrading the water quality, and adversely affecting humans and the environment [1,2]. Water pollution is a phenomenon in which the chemical, physical, and biological quality of natural waters is harmfully affected by the discharge of waste materials such as sanitary sewage [2,3], urban runoff [4], industrial waste [5], agricultural waste [6], animal husbandry effluents [7], vehicle-and traffic-related organic pollutants [8], and other industrial, urban, and agricultural waste materials [9].…”