Unusual bacterial growth observed in Miehikkälä lakes in Finland

In Miehikkälä, Kymenlaakso, unusual observations were made last summer that may be of historical significance. Two lakes in the area have displayed pink mats of bacterial growth. Recent research from the University of Jyväskylä has identified that this bacterial population belongs to the Acidobacteraceae family, likely within the Belnapia genus. According to the university, this is probably the first time Belnapia bacteria have been observed in a substantial mass in a lake.

Krista Rantamo, an environmental inspector responsible for local environmental matters in Miehikkälä, described the situation as exceptional, noting its uniqueness.

The origin of the bacterial growth remains a mystery. Residents have reported seeing the colonies in Pitkälampi and Myllylampi multiple times, with the latest sightings occurring in September. It took some time to determine how to investigate the source of the growth, but Rantamo’s former teacher at the University of Jyväskylä ultimately provided assistance. Investigations are ongoing, with researchers still trying to ascertain how the bacteria entered the water systems.

While the effects of these bacteria on health are currently unknown, both environmental and health authorities advise against swimming in the lakes or using their waters if any bacterial growth is visible. This specific bacteria requires light for energy, suggesting it may not be visible during the darker months of the year. If any bacterial mats continue to be found, authorities are interested in all observations related to environmental protection, which can be reported via email.