Unfortunately we have had another bloom of the blue-green alga Microcystis aeruginosa at Talley Lakes nature reserve in Carmarthenshire.
Microcystis aeruginosa is a fairly common, single-celled but colonial cyanobacterium found in freshwater habitats. It proliferates readily (known as a ‘bloom) in the right conditions- which occur when nutrient levels rise. It produces harmful toxins, which during a bloom can reach levels that cause both the water and the scum in the area to be toxic to humans and animals (including both livestock and pets).
We aren’t currently sure what’s causing the bloom at Talley, but the problem is being investigated by staff from Natural Resources Wales. However until the bloom has died back we would discourage any contact of the water at the site.
The lakes were once oligotrophic (very low nutrient) but are now, like many freshwater lakes and ponds in Wales, subject to eutrophication (increasing nutrient levels). Over many years this is causing the loss of some plants as well as contributing to the increased risk of algal blooms. We have been working in partnership with Natural Resources Wales to monitor, investigate and try and identify what can be done to mitigate this.
WTSWW are very grateful to Natural Resources Wales for their assistance and their continued testing of the water quality. We shall publicise when water quality levels are again deemed safe.