Annachullion Lough ASSI

Physiographical interest of this largely spring - fed lough is related to the presence of calcium carbonate deposits, or marl, which are precipitated out of the calcium - rich water to produce a marl lake. Annachullion is one of the best examples of this lake type in Northern Ireland and is notable for its clear water and very low phytoplankton productivity.

The lough exhibits the natural sucession from open water to terrestrial vegetation and includes a number of unusual plant communities, in addition to several rare plant species.

The aquatic vegetation is of particular importance, as it contains one of the most diverse and extensive submerged growths of stoneworts found in Northern Ireland.