Comprehensive Insight into Lake Nasser Environment: Water Quality and Biotic Communities—A Case Study before Operating the Renaissance Dam

Abstract

This study focused on the monitoring and assessment of aquatic ecosystem functioning based on the abiotic and biotic features of Lake Nasser in the post-flood and pre-flood periods as the last ones before water storing behind the Grand Ethiopian Renaissance Dam. The physicochemical parameters, distribution and structure of biotic communities, including bacteria, phytoplankton, zooplankton, macrophytes, epiphytes and fish were analyzed at 15 sites. The values of most parameters (primarily temperature, total suspended solids, pH, orthophosphates, carbonates, sulphates and some cations) were higher in the pre-flood period, whereas higher values of conductivity, total dissolved solids, total solids, nitrites, nitrates, chemical oxygen demand, bicarbonates and chlorophyll a were recorded in the post-flood period. Cyanobacteria-dominated phytoplankton and total coliform bacteria were more abundant in the pre-flood period, and especially at sites 10–15, whereas higher abundances of zooplankton were recorded in the post-flood period. All these changes in parameters were significantly differentiated, and only the concentrations of dissolved oxygen, biochemical oxygen demand, ammonium and silicates were at similar level in both periods. The study also indicated that environmental factors had affected the macrophyte distribution and the adaptation of the invasive species Myriophyllum spicatum to thrive under different environmental factors in the lake. Besides, macrophytes provided the habitat to other aquatic organisms, especially epiphytes, and also helped maintaining the good water quality, nutrient cycling and stabilizing rivers’ and lakes’ banks. Generally, these conditions were rather favorable for biological processes and fish production.

Influence of the industrial pollutant on water quality, radioactivity levels, and biological communities in Ismailia Canal, Nile River, Egypt

“…The BOD and COD values showed significant spatial variations ( P < 0.01), ranging from 0.40 to 5.80 mg/l and 2.00 to 12.40 mg/l, respectively. BOD and COD are generally indicators of organic pollution (Elsayed et al 2019 ; Goher et al 2021 ). The discharge of industrial effluents was responsible for the maximum COD value measured at the station (8) during two seasons, consistent with the results obtained by Hussien et al ( 2023 ) in the Nile River, El Sayed et al ( 2023 ) in the Ismailia Canal, and Talab et al ( 2016 ) in the Nile Rayahs.…”

Characterization of cyanobacterial isolates from freshwater and saline subtropical desert lakes

“…However, the current cbbL sequence was the first record for an isolate belonging to the genus Merismopedia , generating cbbL data for this genus in lakes. However, the genus Merismopedia has been recorded, through a microscopic survey, as a major component of Cyanobacterial blooms in Lake Nasser (Goher et al 2021 ).…”

Phytoplankton and Bacterial Dynamics Related to the Physicochemical Characteristics of Manzala Lake Water, Egypt

“…On another note, the enumeration of microbial indicators such as the total (TC) and fecal coliforms (FC) as well as Enterococcus spp. is used internationally on a wide range for water quality evaluations and health hazard assessments of fresh or surface water such as lakes, rivers, and others (Newall et al, 2015;Al-Afify et al, 2019;Goher et al, 2021). In this study, the enumerations of TC, FC, and fecal streptococci (FS) were done using most probable number (MPN) techniques.…”