Havsvass

Havsvass is the Danish term for seawater, the saline water that makes up the world's oceans and seas. It is distinct from freshwater and brackish water and is the primary medium in marine and coastal environments. In scientific and educational contexts, havsvass describes the properties, composition, and dynamics of ocean water as observed in measurements and models.

Physical and chemical properties: The average salinity of open-ocean havsvass is about 35 practical salinity units (psu). Its density is typically around 1.025 g/cm3 at 15C, increasing with higher salinity and decreasing with temperature. Major ions include sodium and chloride, with sulfate, magnesium, calcium, and potassium present in smaller amounts. The pH of surface havsvass is often near 8, and dissolved oxygen varies with depth and biological activity.

Occurrence and processes: Havsvass covers most of the planet and interacts with coastal zones through tides, currents, and mixing. In estuaries, seawater can intrude into freshwater systems, creating brackish conditions that support unique habitats. Evaporation can raise salinity in arid regions, while precipitation and river input reduce it. Climate change affects havsvass through changes in temperature, sea level, and circulation patterns.

Human relevance: Havsvass is central to marine ecosystems and climate research. It influences coastal engineering, shipping, desalination, and fisheries. Routine monitoring includes salinity and temperature profiles collected with CTD instruments, salinometry, and autonomous sensors.

See also: Seawater, Oceanography, Salinity, Desalination, Coastal ecology.