Hydrodictyon reticulatum (water net)

Hydrodictyon reticulatum, a very invasive nuisance alga, is commonly known as ‘water-net’ reflecting the net-like structure of its sack or membrane-like colonies.

Over the past 20 years it has become more common and widely distributed in ponds, lakes and rivers in the British Isles.

Water net is a serious nuisance because it

clogs waterways and irrigation ditches,
taints potable water,
causes economic losses to trout ﬁsheries,
smothers aquatic plants and fauna
adversely impacts boating, fishing, swimming and tourism

The rapid spread of the water net is believed to be a response to elevated and extended summer water temperatures and low river flows caused by climate change.

Species detail

Hydrodictyon reticulatum cells are

cylindrical to oblong-oval, up to 15mm long
2-4 adjacent cells connected by their edges and forming 5-6-sided meshes

Meshes combine to form colonies or mats

a single-layered membrane or sac-like network of several thousand cells
free-ﬂoating or secondarily attached
reaching over 50cm long
meshes clearly visible in large colonies

Taxonomy

Find out about the shape, size and structure of water net.
Distribution and habitat

Discover where in the world Hydrodictyon reticulatum appears and where it is currently spreading to.
Biology

Hydrodictyon reticulatum growths can taint the water in drinking water reservoirs. Learn more about the reproduction process and physiology of water net.
Ecological impact

While water net has a range of negative impacts on the waters it grows in, it is also believe to have some positive impacts. Find out more about the negative and positive impacts of Hydrodictyon reticulatum as well as why its rapid growth is thought to be a response to climate change.
References

Get reference material for Hydrodictyon reticulatum.