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Apparent removal of the transient tracer carbon tetrachloride from anoxic seawater
Author(s) -
Krysell Mikael,
Fogelqvist Elisabet,
Tanhua Toste
Publication year - 1994
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/94gl02336
Subject(s) - anoxic waters , tracer , seawater , carbon tetrachloride , oxygen , water mass , carbon fibers , structural basin , environmental chemistry , bottom water , geology , environmental science , oceanography , chemistry , geomorphology , materials science , physics , organic chemistry , composite number , nuclear physics , composite material
Two chlorofluorocarbons (CFC‐11 and carbon tetrachloride, CCl 4 ) widely used as tracers for dating water masses, were measured in the Gotland Basin of the Baltic Sea. At the time of the survey, the bottom water of the basin had remained stagnant for 15 years and anoxic for about the same period of time, and the concentrations of both CFC‐11 and CCl 4 decrease dramatically with depth below the mixed layer. Furthermore, the ratio of CFC‐11 to CCl 4 increases with depth under the mixed layer along with a steep decrease in oxygen concentration. This is contrary to what would be expected from the atmospheric histories. The most plausible explanation for this is that there is a mechanism whereby the CCl 4 is removed from the water mass under anoxic and suboxic conditions.