There are some alarming parallels between the harmful algal blooms (HABs) in Kenya's Lake Victoria and those in Lake Erie, a new study has found.
By studying the Winam Gulf, a section of Lake Victoria with conditions similar to those predicted for a warming Lake Erie, researchers have cataloged the genetic makeup of cyanobacteria responsible for these blooms.
The research identified cyanobacteria such as Dolichospermum, Microcystis and Planktothrix as key contributors to HABs in the Winam Gulf, mirroring those in Lake Erie.
This genetic cataloging, published in Applied and Environmental Microbiology, is the first of its kind in the region.
Why This Matters
HABs, caused by cyanobacteria in the water, produce toxins that can be deadly to humans, livestock and wildlife. As the planet warms, conditions in which cyanobacteria thrive are becoming more abundant.
Conditions in Lake Victoria are favorable to HABs year-round and so serve as a model for Lake Erie as it becomes increasingly warm in years to come.
"Understanding the toxigenic capability of the Lake Victoria blooms is a first step in developing protocols to inform residents about such risks so that they may change their water use during intense bloom periods," George Bullerjahn, senior author of the new study, said in a statement.
What is Cyanobacteria?
Cyanobacteria, often called blue-green algae, are microorganisms that thrive in nutrient-rich, warm waters. When conditions are favorable, they multiply rapidly, forming clouds of green algae known as cyanobacterial HABs.
These blooms can release toxins into the water, which cannot be neutralized by boiling. In fact, boiling contaminated water can exacerbate the problem by breaking open the bacteria and releasing more toxins.
What to Know
The study revealed that Dolichospermum was the dominant bloom-forming cyanobacteria in Winam Gulf, often accompanied by Microcystis, which produces the liver-damaging toxin microcystin.
Researchers also identified over 300 gene clusters responsible for producing a wide array of molecules, some of which may interact to amplify their harmful effects.
"Our collaboration wanted to study not only harmful algal blooms, but also the social consequences of HABs in the context of the Winam Gulf being a model for a warming Lake Erie," lead author Lauren Hart said in the statement.
Co-author Gregory Dick added: "Lauren's work is a great example of how environmental genomics can address longstanding questions, such as which organism is producing known toxins, as well as uncover genetic potential for production of a vast diversity of other molecules of interest, some of which we didn't even know to look for."
The findings were particularly concerning for immunocompromised individuals, who are particularly susceptible to the effects of the toxins.
While water is treated before drinking in the U.S., toxins from HABs can enter the human body through several pathways, including breathing when they become airborne and absorption through the skin when swimming.
What Happens Next
The findings serve as a wake-up call for both local and global communities.
In Kenya, the research is a stepping stone to developing strategies to warn residents about toxic blooms and promote safe water usage.
In North America, the study underscores the need for proactive measures to mitigate the impact of climate change on Lake Erie and other lakes across the continent.
By understanding how HABs evolve in Lake Victoria's warm waters, researchers hope to predict similar outbreaks in the Great Lakes.
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Reference
Hart, L. N., Zepernick, B. N., Natwora, K. E., Brown, K. M., Obuya, J. A., Lomeo, D., Barnard, M. A., Okech, E. O., 2022-23 NSF-IRES Lake Victoria Research Consortium, Kiledal, E. A., Den Uyl, P. A., Olokotum, M., Wilhelm, S. W., McKay, R. M., Drouillard, K. G., Sherman, D. H., Sitoki, L., Achiya, J., Getabu, A., ... Dick, G. J. (2025). Metagenomics reveals spatial variation in cyanobacterial composition, function, and biosynthetic potential in the Winam Gulf, Lake Victoria, Kenya. Applied and Environmental Microbiology. https://doi.org/10.1128/aem.01507-24
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