2024年12月30日 · Seawater, water that makes up the oceans and seas, covering more than 70 percent of Earth’s surface. Seawater is a complex mixture of 96.5 percent water, 2.5 percent salts, and smaller amounts of other substances, including dissolved inorganic and organic materials, particulates, and a few atmospheric gases.

Seawater of normal salinity at 0° C (32° F) in equilibrium with the atmosphere will contain about eight millilitres per litre of dissolved oxygen and 14 millilitres per litre of dissolved nitrogen. Dissolved nitrogen is essentially an inert constituent , but dissolved oxygen plays a fundamental role in the growth and decay of organisms and so ...

2024年12月30日 · Seawater - Salinity, Minerals, Oceans: The principal components of seawater are listed in the table. In contrast to the behaviour of most oceanic substances, the concentrations of the principal inorganic constituents of the oceans are remarkably constant.

2024年12月30日 · Seawater - Salinity, Composition, Oceans: The oceans probably achieved their modern characteristics 2 to 1.5 billion years ago. The chemical and mineralogical compositions and the relative proportions of sedimentary rocks of this age differ little from their Paleozoic-era counterparts (those dating from about 541.0 to 251.9 million years ago).

Marine ecosystem - Salinity, Temperature, Oxygen: The physical and chemical properties of seawater vary according to latitude, depth, nearness to land, and input of fresh water. Approximately 3.5 percent of seawater is composed of dissolved compounds, while the other 96.5 percent is pure water.

Seawater is a complex mixture of 96.5% water, 2.5% salts, and small amounts of other substances. Much of the world’s magnesium is recovered from seawater, as are large quantities of bromine. In certain parts of the world, sodium chloride (table salt) is obtained by evaporating seawater. In addition, desalted seawater can theoretically furnish ...

2024年12月30日 · Seawater - Dissolved Organic, Nutrients, Salts: Processes involving dissolved and particulate organic carbon are of central importance in shaping the chemical character of seawater. Marine organic carbon principally originates in the uppermost 100 metres of the oceans where dissolved inorganic carbon is photosynthetically converted to organic ...

2024年12月30日 · Seawater - Density, Pressure, Salinity: The density of a material is given in units of mass per unit volume and expressed in kilograms per cubic metre in the SI system of units. In oceanography the density of seawater has been expressed historically in …

2024年12月30日 · Seawater - Salinity, Distribution, Oceans: A discussion of salinity, the salt content of the oceans, requires an understanding of two important concepts: (1) the present-day oceans are considered to be in a steady state, receiving as much salt as they lose, and (2) the oceans have been mixed over such a long time period that the composition of ...

2024年12月30日 · Seawater of 35 psu has a specific heat of 0.932 compared with 1.000 for pure water. Pure water freezes at 0 °C and boils at 100 °C (212 °F) under normal pressure conditions. When salt is added, the freezing point is lowered and the boiling point is raised.