- Bottom water
Bottom water is the lowermost
water mass in awater body , by its bottom, with distinct characteristics, in terms ofphysics ,chemistry , andecology .Oceanology
In
oceanology , bottom water is by theocean floor . It has characteristics are markedly distinct from the above layer in terms ofoxygen content,salinity , bulktemperature (characteristic temperature), and hencedensity .The
Antarctic Bottom Water is the source of most bottom water in southern parts ofPacific Ocean ,Indian Ocean andAtlantic Ocean , and even in parts of the North Atlantic. Bottom waters flow very slowly, driven mainly by slope topography and differences in temperature and salinity, especially compared towind -driven surfaceocean current s.The bottom water of the
Arctic Ocean is more isolated, due to the topography of the Arctic ocean floor and the surroundingArctic shelves .Estuaries
Bottom water by an
estuary of a river discharging into a saline body exhibits peculiar transport ofmud . Hue to fresh/saline water intermixing by the estuary, a horizontalisohale gradient is created, with lower salinity levels upstream, which generates the upstream flow of the bottom water. Mud particles carried by river begin settling down as the current andturbulence decrease. When the particles nearly reach the floor, they are carried back to the head of estuary to accumulate at the point where the salinity of the surface and bottom waters become comparable and the bottom flow decreases. This process results is a distinguished pile of mud at this point. [David E. Alexander, Rhodes Whitmore Fairbridge (eds.) (1999) "Encyclopedia of Environmental Science", ISBN 0412740508, [http://books.google.com/books?id=Y0iX2z48qkUC&pg=PA238&dq=%22bottom+water%22+-antarctic&lr=&sig=MaLNakB9LncHKKlDNjKLmEDCW9Q p.238] ]Lake hydrography
Bottom water of
lake s may feature lower level ofoxygen , to the point of completely vanished dissolved oxygen (i.e., becominganaerobic ), and higher levels ofchlorinity and organic-inducedacidity . In many lakes, especially in the zones ofcontinental climate , summer heating and winter cooling create strong vertical temperature gradients which oppose watewr intermixing, resulting in the periods of summer and winter thermallake stratification . They are intervened by bottom water overturning, which happens inautumn (autumn overturn) and in spring (spring overturn) due to equalizing of temperature gradients and the resulting easier intermixing by wind and other sources of turbulence. [Milton Joseph Rosenau, George Chandler Whipple, John William Trask, Thomas William Salmon (1921) "Preventive Medicine and Hygiene" , [http://books.google.com/books?id=9E82AAAAIAAJ&pg=PA1031&lpg=PA1031&dq=%22bottom+water%22+overturn&source=web&ots=xnPMmq38_8&sig=3DC54Sy_LpoDc4yAz_0En8Ypyzc p. 1031] ] [ [http://www.waterencyclopedia.com/Hy-La/Lakes-Physical-Processes.html "Lakes: Physical Processes"] ]ee also
*
Surface water References
Wikimedia Foundation. 2010.