Limnological status of Lake Oloidien in Kenya’s Rift Valley between 2020 and 2021

Abstract

Water samples were collected between August 2020 and March 2021 and analyzed for physicochemical parameters to ascertain the current limnological status of Lake Oloidien. The maximum mean depth of the lake recorded was 7.7 m in November, which corresponded with a high water transparency value (69.0 ± 3.4 cm) in the same month. There were no significant variations in temperatures among the sampled stations, mean ranges were 23.15 ± 1.15°C and 23.93 ± 1.09°C.Dissolved oxygen (DO) concentrations were high in September (13.99 ± 0.01 mg L-1) with depth profiles of DO between August 2020 and March 2021 differing significantly (p = 7.955E-06). Conductivity mean values ranged from 414.0 ± 23.89 μS cm-1 and 730 ± 11.54 μS cm-1, with January recording the highest value while October recorded the least value. It was observed that only pH levels had significant variation across the months sampled with p = 0.506 and a mean of 8.55 ± 0.56. The mean values for nitrates ranged from 2.04 ± 1.30 mg L-1 and 4.78 ± 0.045 mg L-1 across the months sampled and the highest chlorophyll-a levels were recorded in August at 83.3 ± 56.06 mg L-1. In the past years, the lake has been alkaline-saline with high conductivity levels, and chances of fish survival were limited. Currently, the environmental factors are now favourable for fish survival.