Visitors to Godmanchester Nature Reserve have been advised to take care around Roman Lake where theres been a report of potentially toxic Blue-Green algae. Signs were put up to warn of the danger at the Cow Lane site but they were stolen and have not been replaced. There has been a problem with algae at the reserve, which is managed by the Wildlife Trust, for the past two years, but it comes and goes. Blue-Green algae, also known as cyanobacteria, can produce toxins, which can harm humans, but are especially harmful to dogs. When they spread over a large surface area, they are referred to as blooms. Its impossible to tell by sight whether a particular patch is toxic or not and algae are not always present on the surface. Owners who think their dog has been in contact with affected water, even by licking it off its fur, are advised to look out for symptoms, such as lethargy, diarrhoea or convulsions. If pets display any of these signs, the advice is to take them to a vet immediately, as ingesting the toxins can prove fatal for a dog. A spokesman for the Bedfordshire, Cambridgeshire, Northamptonshire Wildlife Trusts, said the presence of this particular strain of algae, had not been confirmed and it had likely been dispersed by rain. However, if theres a period of dry weather, it is likely to reoccur and dog owners are being advised to keep their pets away from the lake, especially if they see a milky-blue film on the surface. If people come into contact with affected water and develop eye, ear or skins reactions, flu-like symptoms or diarrhoea, they should contact a doctor as soon as possible. There are no restrictions at the two other lakes at the reserve, which are unaffected by the algae. INFORMATION: For more details, visit www.wildlifebcn.org/reserves/godmanchester.