Seasonal variation of algal diversity with reference to water quality in Jagadishpur Reservoir, Nepal

Abstract

The study of the importance of physicochemical parameters of water for algal growth and development in Jagdishpur Reservoir was carried out in the present research. Occurrence of algal species and values of water quality parameters also indicate the ecological nature and the present status of the reservoir. Water samples were collected from Jagdishpur Reservoir in Kapilvastu District (Nepal), in two seasons (wet and dry). The following physicochemical parameters of water were analyzed: temperature, pH, dissolved oxygen, alkalinity, concentration of nitrates and phosphates, free CO2, hardness, conductivity, total dissolved solids. The values of free CO2, hardness, phosphate, temperature, and dissolved oxygen were high in wet season while alkalinity, nitrate, conductivity and total dissolved solid were high in dry season. Altogether 81 algal species belonging to 53 genera and 6 classes were recorded. Higher number of algal species was recorded in the dry season rather than in the wet season. The highest number of species was noted among Chlorophyceae, followed by Cyanobacteria > Bacillariophyceae > Euglenophyceae > Crysophyceae and Dinophyceae. Cosmarium had the highest number of species (13) among all genera. During the wet season, Cosmarium, Calothrix and Phormidium were the genera with the highest number of species while Bulbochaete, Trachelomonas and Gomphonema were genera with the lowest number of species. During the dry season, Cymbella, Cosmarium and Rhopalodia were genera with highest number of species while Euglena, Gloeotrichia and Trachelomonas were genera with lowest number of species. Algal diversity was positively correlated with the increase of alkalinity, conductivity and TDS, while negatively correlated with free CO2, hardness, concerntration of phosphates and nitrates, DO, pH and temperature. Shannon–Weiner diversity index value was higher during the dry season than in the wet season.

Seasonal variation of macrophytes related to hydrochemical parameters in Ghodaghodi lake, Nepal

“…Hydrochemical parameters of lake water: Results of physiochemical analysis of water samples are presented in Table 2. In the present study, the mean value of water temperature was higher in pre monsoon season (28.85±0.49) than in post-monsoon season (16.99±0.98) (Table 2), which supported the results of previous researchers (Thapa & Saund, 2013;Chaudhary & Devkota, 2018;Pokhrel et al, 2021). A high temperature of surface water was observed in the pre-monsoon season, which could be due to the influence of atmospheric temperature.…”

“…The mean value of conductivity was lower in the post monsoon season (183.16 ±17.32 μS cm -1 ) than in pre-monsoon season (178.25±28.75 μS cm -1 ). Similar results were reported by Pant et al, (2020) and Pokhrel et al, (2021) but the average conductivity of the reservoir seems to have decreased in the present study in comparison to values recorded by Pokhrel et al, (2021). That may be due to the decomposition of organic matter, input of ions, inlet, temperature of the water and total solids.…”

“…The highest value of TDS (92.53 ±5.20 mg dm -3 ) was observed in post monsoon and the lowest (90.34 ± 18.35mg dm -3 ) in the pre monsoon season, the results were similar to those in Jagadishpur reservoir (Pokhrel et al, 2021) which was also a tropical lake. TDS might be increased in water due to the intensification of anthropogenic activity.…”

“…Studies relating to aquatic and wetland flora have been carried out by previous researchers in various parts of Nepal (Sah, 1997;Bhandari, 1998;Burlakoti & Karmacharya, 2004;Kunwar & Devkota, 2012;Bhusal & Devkota, 2020;Pokhrel et al, 2021). Several scattered reports are available on the lowland lakes of Nepal; however seasonal diversity of aquatic macrophytes are comparatively less studied in Ghodaghodi lake, which is one of the most concerned wetlands.…”

Environmental parameters drive the phytoplankton community structure: a case study in Baghdad Tourist Island Lake, Iraq

“…The total number of phytoplankton ranged from 280 to 323 Cells*10 4 /L at sites 1 and 3, respectively in the dry season and 221 to 307 Cells*10 4 /L at sites 1 and 3 in the wet season (Figures 3 and 4). Pokhrel et al [41] noticed a high algal diversity in the dry season than in the wet season and they interpreted it on the basis of the nutrient dilution factor in the wet seasons. .…”