Sea salt in the context of "Seawater"

Seawater, or sea water, is water from a sea or ocean. On average, seawater in the world's oceans has a salinity of about 3.5% (35 g/L, 35 ppt, 600 mM). This means that every kilogram (roughly one liter by volume) of seawater has approximately 35 grams (1.2 oz) of dissolved salts (predominantly sodium (Na) and chloride (Cl) ions). The average density at the surface is 1.025 kg/L. Seawater is denser than both fresh water and pure water (density 1.0 kg/L at 4 °C (39 °F)) because the dissolved salts increase the mass by a larger proportion than the volume. The freezing point of seawater decreases as salt concentration increases. At typical salinity, it freezes at about −2 °C (28 °F). The coldest seawater still in the liquid state ever recorded was found in 2010, in a stream under an Antarctic glacier: the measured temperature was −2.6 °C (27.3 °F).

Seawater pH is typically limited to a range between 7.5 and 8.4. However, there is no universally accepted reference pH-scale for seawater and the difference between measurements based on different reference scales may be up to 0.14 units.

The Burgas Lakes (Bulgarian: Бургаски езера, Burgaski ezera) or Burgas Wetlands (Бургаски влажни зони, Burgaski vlazhni zoni) are a group of coastal lakes of varying saltiness located around the Bulgarian city of Burgas in the proximity of the Black Sea. They constitute the largest group of lakes in the country and comprise some of Bulgaria's biggest and most important lakes.

The lakes' total area (including swamps, marshes, ponds and other reservoirs) amounts to 95 km, of which 33.30 km are either proclaimed or proposed protected areas that are inhabited by a large number of locally or globally endangered species of birds, fish and mammals. Apart from this, the Burgas Lakes are also of economic importance, used to obtain sea salt and curative mud, as well as to supply the local economy with fresh water, in the case of Lake Mandrensko.

Yancheng (simplified Chinese: 盐城; traditional Chinese: 鹽城; pinyin: Yánchéng), formerly known as Yandu, is a prefecture-level city in the eastern coastal Jiangsu province, People's Republic of China. As the city with the largest jurisdictional area in Jiangsu, Yancheng borders Lianyungang to the north, Huai'an to the west, Yangzhou and Taizhou to the southwest, Nantong to the south, and the Yellow Sea to the east. Formerly a county, the current Yancheng city was founded on January 18, 1983.

Yancheng, literally "Salt City", is named after the salt harvest fields surrounding the city. According to historical records, collection and production of sea salt in the region began as early as 119 BC, during the Western Han dynasty, when the settlement on the current location of Yancheng was named Yandu County (盐渎县). According to the 2020 census, Yancheng had a registered population of 6,709,629, with 1,733,591 inhabitants in its built up area comprising the districts of Tinghu and Yandu.

Lake Pomorie (Bulgarian: Поморийско езеро, Pomoriysko ezero) is the northernmost of the coastal Burgas Lakes, located in the immediate proximity of the Black Sea and the Bulgarian town of Pomorie. It has an area of 8.5 km (reaching 10 km together with the adjacent damp zones) and has an elongated shape with a length of 6.7 km and width of 1.8–2 km. Divided from the sea by a narrow strip of sand (spit) and an artificial dike, the lake is an ultrasaline natural lagoon.

Lake Pomorie is a protected area since January 2001. Sea salt is obtained in the north part and curative mud in the south. Located on the Via Pontica bird migration route, the lake is inhabited by 215 species of birds, 4 of which globally endangered, and is thus of ornithological importance. Since the 2010s, the lake has become a wintering site for thousands of greater flamingoes.