Strange phenomenon on Lake Malawi explained

Greening in Lake Malawi

The Ministry of Forestry and Natural Resources has come out to explain the greening of water in some parts of the central and eastern regions of Lake Malawi which occurred over the weekend.

Writing on her Facebook page, Minister Nancy Tembo said the greening is caused by a bloom of phytoplankton of the cyanobacteria type called Kang’ona.

She warned the public the cyanobacteria is toxic and itchy and can lead to death when swallowed in large volumes especially by children.

Tembo explained this is also the case in Monkey Bay due to the heavy winds which have prevailed on the lake for over two weeks.

“The persistent southeasterly winds coupled with low water temperatures during this time of the year induces mixing of nutrient rich bottom waters especially in the southern end of the lake. The water then becomes eutrophic [eutrophication is the process in which a water body becomes overly enriched with nutrients, leading to plentiful growth of simple plant life].

Tembo: This phytoplankton bloom is a natural phenomenon that periodically occurs in the lake

“This phytoplankton bloom is a natural phenomenon that periodically occurs in the lake,” said the Minister.

She assured the greening which also happened in 2009, 2013 and 2019 should fade away within a week or two.

In an interview monitored on ZBS, Director of Fisheries Dr. Friday Njaya appealed to the public to be alert and warned against consuming dead fish which may be found floating on the lake resulting from the development.

According to an eyewitness account, the water was clear in the morning but suddenly became green and thick on the surface.