Science dealing with the properties, distribution, and circulation of water on and below the earth's surface, and atmosphere.

The branch of science concerned with the interrelationship of organisms and their ENVIRONMENT, especially as manifested by natural cycles and rhythms, community development and structure, interactions between different kinds of organisms, geographic distributions, and population alterations. (Webster's, 3d ed)

Circulation of water among various ecological systems, in various states, on, above, and below the surface of the earth.

The flow of water in enviromental bodies of water such as rivers, oceans, water supplies, aquariums, etc. It includes currents, tides, and waves.

Large natural streams of FRESH WATER formed by converging tributaries and which empty into a body of water (lake or ocean).

I'm sorry for any confusion, but "Svalbard" is not a medical term and does not have a medical definition; it is a geographical location, an archipelago in the Arctic Ocean, north of Norway.

Environments or habitats at the interface between truly terrestrial ecosystems and truly aquatic systems making them different from each yet highly dependent on both. Adaptations to low soil oxygen characterize many wetland species.

A functional system which includes the organisms of a natural community together with their environment. (McGraw Hill Dictionary of Scientific and Technical Terms, 4th ed)

The unconsolidated mineral or organic matter on the surface of the earth that serves as a natural medium for the growth of land plants.

A thick mass of ICE formed over large regions of land; RIVERS; LAKES; ponds; or SEAWATER.

Any significant change in measures of climate (such as temperature, precipitation, or wind) lasting for an extended period (decades or longer). It may result from natural factors such as changes in the sun's intensity, natural processes within the climate system such as changes in ocean circulation, or human activities.

Water particles that fall from the ATMOSPHERE.

The longterm manifestations of WEATHER. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)

The variety of all native living organisms and their various forms and interrelationships.

The protection, preservation, restoration, and rational use of all resources in the total environment.

Water containing no significant amounts of salts, such as water from RIVERS and LAKES.

The pattern of any process, or the interrelationship of phenomena, which affects growth or change within a population.

The monitoring of the level of toxins, chemical pollutants, microbial contaminants, or other harmful substances in the environment (soil, air, and water), workplace, or in the bodies of people and animals present in that environment.

Theoretical representations that simulate the behavior or activity of systems, processes, or phenomena. They include the use of mathematical equations, computers, and other electronic equipment.

A clear, odorless, tasteless liquid that is essential for most animal and plant life and is an excellent solvent for many substances. The chemical formula is hydrogen oxide (H2O). (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)

Ecological and environmental entities, characteristics, properties, relationships and processes.

The activated center of a lymphoid follicle in secondary lymphoid tissue where B-LYMPHOCYTES are stimulated by antigens and helper T cells (T-LYMPHOCYTES, HELPER-INDUCER) are stimulated to generate memory cells.