Assessing water quality and classifying trophic status for scientifically based managing the water resources of the Lake Timsah, the lake with salinity stratification along the Suez Canal

Abstract

Lake Timsah is considered as the biggest water body at Ismailia City with a surface area of 14 km2. It is a saline shallow water basin lies approximately mid-way between the south city of Suez and the north city of Port Said at 30o35′46.55“N and 32o19′30.54″E. Because it receives water with high and low salinities, salinity stratification is producing in the Lake Timsah, with values of 14–40‰ for the surface water and over 40‰ for the bottom water. The temperature of the lake water decreased to below 19 °C in the winter and rose to above 29 °C in the summer; the concentration of dissolved oxygen ranged between 6.5 and 12.2 l−1 and the pH fluctuated between 7.9 in its lower value and 8.2 in its higher value. Water transparency was very low as indicated by Secchi disc readings recorded during this study and varied between 0.3 and 2.7 m. The main chemical nutrient (phosphorus) reached its highest levels of 96 µg l−1 in winter and their lowest values of 24 µg l−1 during summer. This nutrient concentration is high especially by comparing with those of unpolluted marine waters, but is typical of the more eutrophic coastal waters worldwide. The composition and abundance of phytoplankton with dominancy of diatoms and increased population density (20,986 cell l−1) reflect the eutrophic condition of the lake. The intensive growth of phytoplankton was enriched by high concentration of chlorophyll a with annual values ranged between 6.5 and 56 µg l−1. The objective of the present work was quantitative assessment of the quality of the water of the Lake Timsah using different approaches. During the present study, three different approaches were applied for the quantitative assessment of Lake Timsah water quality: the trophic state index (TST); trophic level index (TLI) and water quality index (WQI). Application of the trophic state and trophic level indices (TSI & TLI) revealed that the Lake Timsah has trophic indices of 60 and 5.2 for TSI and TLI, respectively. Both indices reflected the eutrophic condition of the lake waters and confirmed that the eutrophication is a major threat in the Lake Timsah. On the other hand, the WQI calculated for the Lake Timsah during the present study with an average of 49 demonstrated that the water of the Lake Timsah is bad and unsuitable for main and/or several uses. Moreover, WQI allows accounting for several water resource uses and can serve a more robust than TSI and/or TLI and can be used effectively as a comprehensive tool for water quality quantification. In conclusion, the three subjective indices used for the assessment process for the lake water are more suitable and effective for needs of the sustainable water resources protection and management of the Lake Timsah.

Phytoplankton population as alarming warning bioindicator of water pollution in El-Temsah Lake, Egypt

“…Dinophyceae and Euglenophyceae were rarely recorded and representing only 1.50 and 0.72 % of the whole standing crop with an annual average of 14605 and 4537 cell/L, respectively (Table 2). These taxonomic groups and species abundance showed more or less consistent with prior studies in the same lake (Nassar and Shams El-Din 2006;Gaballa 2014;El-Serehy et al 2018).…”

“…Cyclotella kutzingiana and Diatoma vulgare were also highly recorded during the study period, with an average of 44217.5 and 39460 cell/L, respectively. In a previous study, diatoms were the dominant group in El-Temsah lake, representing 56 and 58%, respectively (Gaballa 2014;El-Serehy et al 2018). Chlorophyceae occupied the second predominant position with an annual average of 336547 cell/L comprising 36.24% of the total standing crop.…”

“…Location 6, 2 and 4 showed the greatest score. These ndings may be due to the fact that northern locations are the closet to people communities, leaving them facing a number of agriculture and industrial contaminations over other locations (El-Serehy et al 2018).…”

Evaluation of the efficiency of three different mineral adsorbents in the removal of pollutants in samples from a tropical spring in Northeastern Brazil

“…In this context, the world's surface water reservoirs have been suffering from the excessive supply of nutrients such as phosphorus (P) and nitrogen (N), which accumulate in the system, accounting for one of the main causes of water eutrophication (Yan et al, 2017). Cyanobacterial decomposition interferes with the quality of the aquatic environment, promoting a decrease in the pH of the middle levels, dissolved oxygen, changes in temperature, increased turbidity, and the possibility of release of toxins that can be lethal in water (Almanza et al, 2019; El‐serehy, Abdalla, Al‐Misned, Al‐Farraj, & Al‐Rasheid, 2018).…”

Potential Fishing Zones Estimation Based on Approach of Area Matching Between Thermal Front and Mesotrophic Area

“…Water fertility associated with the tropic status ranging from oligotrophic which has the lowest amount of biological productivity and quite good water quality, mesotrophic which has moderate biological productivity and quite a water quality, and eutrophic which has the highest biological activity and poor water quality. Furthermore, trophic status also calculated using more parameters such as Secchi depth, total Phosphorus, dissolved oxygen, and other nutrient parameters (El-Serehy et al, 2018;Wen et al, 2020). Mesotrophic are potential areas to be used as PFZ, in some locations (north-western North Pacific, archipelagic waters of Spermonde), where higher fish catches are found in the mesotrophic area with a concentration range of 0.2-0.5 mg/m 3 (Nurdin et al, 2017;Zainuddin et al, 2006).…”