Mlaștina Hergheliei

Mlaștina Hergheliei is a mixed-type nature reserve, declared a protected area of national interest by Government Decision no. 2151 of 30 November 2004. It is located in the north-eastern part of the municipality of Mangalia, between the Saturn and Venus resorts, in Constanța County. It covers an area of 98 hectares and forms part of the Natura 2000 site Mlaștina Hergheliei–Obanul Mare și Peștera Movilei. The area represents a former marine gulf separated from the Black Sea by a coastal barrier approximately 1,400 m in length and 80–100 m in width, gradually transformed through sediment accumulation and vegetation growth into a eutrophic marsh. The water depth is shallow, ranging from 50–100 cm, making it unsuitable for swimming but ideal for birdlife. A distinctive feature is the more than 25 vents on the marsh floor, from which bubbles of methane and hydrogen sulphide emerge — mesotermal and sulphurous springs that keep the water at higher temperatures and attract migratory birds even in winter. The area also contains a significant peat deposit. The flora includes halophytic, hygrophilous and mesohygrophilous species, with extensive communities of reeds and cattail. The birdlife is exceptionally diverse for such a small area: whooper swan, white stork, little egret and great white egret, black tern, red-breasted goose (a globally endangered species), greater white-fronted goose, purple heron, ferruginous duck, great white pelican, black-winged stilt, avocet and dozens of other migratory species. The fauna is further complemented by freshwater turtles, frogs and water snakes. The sapropelic mud extracted from the marsh has been used for therapeutic purposes at nearby spa resorts. The site is well worth visiting during migration seasons — spring and autumn — for the remarkable diversity of birdlife concentrated within a small area in the immediate vicinity of the coastline.