Search results
Results from the WOW.Com Content Network
Most water in Earth's atmosphere and crust comes from saline seawater, while fresh water accounts for nearly 1% of the total. The vast bulk of the water on Earth is saline or salt water, with an average salinity of 35‰ (or 3.5%, roughly equivalent to 34 grams of salts in 1 kg of seawater), though this varies slightly according to the amount of runoff received from surrounding land.
A unit of volume is a unit of measurement for measuring volume or capacity, the extent of an object or space in three dimensions. Units of capacity may be used to specify the volume of fluids or bulk goods, for example water, rice, sugar, grain or flour.
With few exceptions, animals consume organic material, breathe oxygen, are able to move, reproduce sexually, and grow from a hollow sphere of cells, the blastula, during embryonic development. Over 1.5 million living animal species have been described —of which around 1 million are insects —but it has been estimated there are over 7 million ...
Aquatic animals generally conduct gas exchange in water by extracting dissolved oxygen via specialised respiratory organs called gills, through the skin or across enteral mucosae, although some are evolved from terrestrial ancestors that re-adapted to aquatic environments (e.g. marine reptiles and marine mammals), in which case they actually ...
a narrow channel of water that connects two larger bodies of water, and thus lies between two land masses. Stream: a body of water with a detectable current, confined within a bed and banks. Stream pool: a stretch of a river or stream in which the water is relatively deep and slow moving. Streamlet: a small stream; rivulet. [38] Subglacial lake
In the life sciences, mass flow, also known as mass transfer and bulk flow, is the movement of fluids down a pressure or temperature gradient. [1] As such, mass flow is a subject of study in both fluid dynamics and biology. Examples of mass flow include blood circulation and transport of water in vascular plant tissues. Mass flow is not to be ...
The amount of water in a stream is measured as discharge (volume per unit time). As water flows downstream, streams and rivers most often gain water volume, so at base flow (i.e., no storm input), smaller headwater streams have very low discharge, while larger rivers have much higher discharge. The "flow regime" of a river or stream includes ...
There are three basic types of freshwater ecosystems: Lentic (slow moving water, including pools, ponds, and lakes), lotic (faster moving water, for example streams and rivers) and wetlands (areas where the soil is saturated or inundated for at least part of the time). Limnology (and its branch freshwater biology) is a study about freshwater ...