The Großes Meer is a naturally formed fen lake (Niedermoorsee) in north Germany that lies between Aurich and Emden near Bedekaspel in the Südbrookmerland region, on the edge of the East Frisian Geest where it transitions to the Ems marshes.

The northern part, by contrast, is used as a leisure and recreation area and has facilities for angling and water sports.

With its extensive belt of reed-beds and the adjacent wetlands the Großes Meer and its surrounds are a breeding area and habitat of regional importance.

Black-tailed godwit, snipe, lapwing, short-eared owl, marsh harrier, hen harrier, bittern, sedge warbler, bluethroat and reed bunting are a few of the species of breeding bird that are important from a conservation perspective.

The former Siersmeer and Heerenmeeder Meer in the southern part of the nature reserve have completely silted up and now form a large expanse of sedge with transitions to grey willow bushes.