Some of our members may know that in September this year we received the news from Natural Resources Wales that a bloom of the blue-green alga Microcystis aeruginosa was confirmed from our 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 specifically caused the Talley bloom, but the problem has been regularly monitored by staff from Natural Resources Wales. We are now delighted to confirm that the lakes have now passed their latest two tests in a row and the nature reserve has been deemed safe again.
Talley Lakes nature reserve consists of two lakes lying in glacial hollows separated by a narrow neck of land. There is a bird hide between the two lakes. The reserve is a Site of Special Scientific Interest (SSSI). The upper, southern lake is almost 16 acres in extent. In summer the flowers and floating leaves of the Yellow and White Water Lily are a striking feature, as is Water-crowfoot. Both Shoreweed and Bladder Sedge still occur, which were recorded back in 1773.
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. Increasing nutrient levels is a significant threat to many of our natural habitats in Wales, which are typified by low nutrient levels- not just open water habitats but also bogs and other wetland sites. Diffuse pollution from agriculture, at a landscape level, is known to be a particular challenge for these sensitive sites.
The Wildlife Trust of South and West Wales are very grateful to Natural Resources Wales for their assistance during the last few months.
More information on visiting Talley Lakes can be found on our website. The lakes are a great place to look for wintering wildfowl.