What is that Stuff Covering the Water?
That thick, reddish ‘porridge’ covering the Chatterton fields is not an algal bloom. It is actually hundreds of thousands of ferns – mosquito ferns, to be precise. Mosquito ferns, the smallest ferns in North America, are tiny, free-floating plants completely adapted to life in the water. Each fern is composed of branching fronds with dense, overlapping, scale-like leaves, and resembles a chubby miniature cedar branch with dangling roots. The species growing on the Chatterton wetlands is ‘Large Mosquito Fern’ (Azolla filiculoides). In spite of its name, it is only 1 to 2 centimetres across. The plants are initially bright green in colour, but develop a reddish tinge as they age and become stressed. Mosquito ferns establish in areas of still water such as ponds or sloughs, and form rapidly expanding mats. Under ideal conditions they are capable of doubling their mass every few days, and can soon dominate entire wetlands, as they now do the Chatterton fields. One of the reasons the ferns
