Benard Mucholwa Simiyu is a PhD student at the Research Department for Limnology, University of Innsbruck, Austria. The award gave him the opportunity to attend the 62nd Annual International Conference on Great Lakes Research at the State University of New York from 10th to 14th of June 2019. The conference was organized by the IAGLR. Hundreds of scientists and other professionals from a wide variety of scientific disciplines with a common interest in the management of large lake ecosystems on many levels participated.
Benard presented his PhD results on “Effects of hydrological changes on water quality and spatial phytoplankton composition in Nyanza Gulf, Lake Victoria, Kenya”. His research focuses on the impacts of water pollution in Nyanza Gulf (1400 km2), one of the largest Gulfs of Lake Victoria. In the past few decades, the Gulf has shown signs of water quality deterioration by the frequent occurrence of the harmful algal bloom of which some have the potential to produce toxins that are harmful to humans and livestock. Consequently, the algal bloom in the Gulf has been associated with fish kills, the shutdown of the drinking water treatment plant in Kisumu from January to March 2004 and reports have also shown the occurrence of the cyanotoxins, Microcystins in water and fish. Some hydrodynamic studies have partly related the decline in water quality in the Gulf to the construction of the Mbita Causeway that linked the mainland and Rusinga Island. This led to blockage of the Mbita Channel, a secondary passage that connected Rusinga Channel and the offshore waters of Lake Victoria. Fortunately, in May 2017, part of the Causeway was removed and replaced by a Mbita-Rusinga Bridge opening part of Mbita Channel (width, 150 m) to connect the Gulf and the main basin. This was expected to increase water exchange between the Gulf and the main basin and thus improve the water quality and reduce phytoplankton biomass in the Gulf. To check on the influence of the main basin on the Gulf, seasonal and spatial investigation of conductivity, water level and phytoplankton composition in the Gulf and the main basin was carried out. The relationship between water level variability and conductivity showed signs of dilution in the Gulf from inflows from the main basin with higher influence observed during the low precipitation period. Comparison with previous studies showed a significant decrease in the biomass of Microcystis sp., which has been associated with toxin production and bloom formation in the Gulf.
Benard Mucholwa Simiyu has a background in Aquatic Ecology with a Master of Science Degree in Environmental Sciences, Specialization in Limnology and Wetlands Ecosystems from the Institute for Water Education (UNESCO-IHE), Netherlands. His thesis focused on the investigation of Toxins in small-sized fish from Nyanza Gulf, Lake Victoria, Kenya and resulted into a publication in the international peer-reviewed open access journal toxins. Before he started his PhD, he worked in the Arthrospira Biomass Dynamics Project in saline Alkaline lakes (Bogoria and Nakuru) at Egerton University. He also worked at the National Environment Management Authority of Kenya where he participated in the process of developing environmental management plans for Lake Olbolossat and Lake Jipe in Kenya and as a part-time lecturer at the Technical University of Kenya. Benard is a member of the International Society for Limnology (SIL) and International Association of Great Lakes Research (IAGLR).
