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CALCIUM CARBONATE SATURATION IN SEAWATER: EFFECTS OF DISSOLVED ORGANIC MATTER 1
Author(s) -
Chave Keith E.,
Suess Erwin
Publication year - 1970
Publication title -
limnology and oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 197
eISSN - 1939-5590
pISSN - 0024-3590
DOI - 10.4319/lo.1970.15.4.0633
Subject(s) - seawater , supersaturation , aragonite , calcium carbonate , precipitation , chemistry , artificial seawater , saturation (graph theory) , carbonate , gypsum , environmental chemistry , calcite , inorganic chemistry , mineralogy , geology , oceanography , paleontology , physics , mathematics , organic chemistry , combinatorics , meteorology
Surface seawater is generally supersaturated with CaCO 3 ; but carbonate will not precipitate from natural seawater in convenient experimental times. If the supersaturation is increased by the addition of Ca 2+ or CO 3 2− ions, precipitation can occur in minutes or hours. Seawater, with 0.1 m Na 2 CO 3 solution added to give a p H of 9.5, will begin rapid CaCO 3 (aragonite) precipitation in as little as 15 min. The length of time between the addition of the Na 2 CO 3 and rapid precipitation increases with an increase in the dissolved organic content of the water. If CaCl 2 , which produces no p H increase, is added to seawater, CaSO 4 ·2H 2 O (gypsum) is the only precipitate that will form within 12 hr.