A salt marsh or saltmarsh, also known as a coastal salt marsh or a tidal marsh, is a coastal ecosystem in the upper coastal intertidal zone between land and open salt water or brackish water that is regularly flooded by the tides. It is dominated by dense stands of salt-tolerant plants such as herbs, grasses, or low shrubs. These plants are terrestrial in origin and are essential to the stability of the salt marsh in trapping and binding sediments. Salt marshes play a large role in the aquatic food web and the delivery of nutrients to coastal waters. They also support terrestrial animals and provide coastal protection.
Syvash or Sivash also known as the Rotten Sea (Ukrainian: Сиваш, Гниле Море; Russian: Сиваш, Гнилое Море; Crimean Tatar: Sıvaş, Çürük Deñiz), is a large system of shallow lagoons on the west coast of the Sea of Azov (northeastern coast of the Crimean Peninsula, Ukraine). Sıvaş (pronounced as [səˈvɑːʃ]) in the Crimean Tatar language means dirt. The total water area: 2 560 km², length: 200 km, width: up to 35 km. The total water/land area of the Sivash system is over 10 000 km².
It nearly cuts the Crimean Peninsula off from the mainland, and serves as a natural border between the Autonomous Republic of Crimea and the Kherson Oblast that passes through Sivash. It is separated from the Sea of Azov by the long (110 km), narrow (max. 500 m) Arabat Spit, broken only at its northern end by the Henichesk Strait, at the mouth of which lies the port town of Henichesk. The Isthmus of Perekop separates Sivash from the Black Sea and connects the Crimean Peninsula to the mainland.