Anthropogenic chlorofluorocarbons in the Black Sea and the Sea of Marmara

Measurements of the distributions of two chlorofluorocarbons, CCl3F (CFC-11) and CCl2F2 (CFC-12), made during the June/July 1988 R. V. Knorr cruise in the Black Sea indicate that CFC-11 is non-conservative relative to CFC-12 in the strongly reducing anoxic waters. A multi-layer model combining horizontal/vertical renewal and vertical diffusion processes was tuned to the distributions of CFC-12 and salinity in suboxic and anoxic waters and used to estimate the residence times of subsurface waters and first-order in situ removal rate constants for CFC-11. The model-calculated residence times were B5 yr in the suboxic zone (80–120 m) and increased to B625 yr at 500 m. The first-order CFC-11 in situremoval coefficients were 0.52 70.19 yr � 1 for the depth range 160–480 m. Based on the observed CFC-12 concentrations, the residence time of cold intermediate layer water (B50–100 m) was estimated to be o5 yr. The residence time of the deep water (100–450 m) in the Sea of Marmara was estimated to be 12–19 yr using a box model tuned to CFC-12, implying an in situ oxygen utilization rate of 10–18mmol kg � 1 yr � 1 . r 2002 Elsevier Science Ltd. All

[1]  G. Friederich,et al.  Chemical variability in the Black Sea: implications of continuous vertical profiles that penetrated the oxic/anoxic interface , 1991 .

[2]  R. Gammon,et al.  Chlorofluoromethanes in the northeast Pacific Ocean: Measured vertical distributions and application as transient tracers of upper ocean mixing , 1982 .

[3]  D. Ross.  The Black Sea and the Sea of Azov , 1977 .

[4]  Temel Oguz,et al.  On the Physical Oceanography of the Turkish Straits , 1990 .

[5]  Gösta Walin,et al.  On the relation between sea‐surface heat flow and thermal circulation in the ocean , 1982 .

[6]  G. Friederich,et al.  Oxidation-Reduction Environments: The Suboxic Zone in the Black Sea , 1995 .

[7]  J. L. Bullister,et al.  Chlorofluorocarbon‐11 removal in anoxic marine waters , 1995 .

[8]  E. Özsoy,et al.  Observations of the Mediterranean inflow into the Black Sea , 1991 .

[9]  S. Doney,et al.  A chlorofluorocarbon section in the eastern North Atlantic , 1992 .

[10]  E. Özsoy,et al.  FILLING OF THE MARMARA SEA BY THE DARDANELLES LOWER LAYER INFLOW , 1993 .

[11]  R. Weiss,et al.  Anthropogenic Chlorofluoromethanes in the Greenland and Norwegian Seas , 1983, Science.

[12]  R. Matear,et al.  Estimation of vertical mixing in the upper ocean at Station P from chlorofluorcarbons , 1997 .

[13]  Steven J. Worley,et al.  COADS Release 2 data and metadata enhancements for improvements of marine surface flux fields , 1998 .

[14]  R. Rasmussen,et al.  Emissions of trace gases from Chinese rice fields and biogas generators: CH4, N2O, CO, CO2, chlorocarbons, and hydrocarbons. , 1990 .

[15]  G. Friederich,et al.  Bottle and Pumpcast Data from the 1988 Black Sea Expedition , 1988 .

[16]  Ǐ. Salihoǧlu,et al.  The distribution of man-made and naturally produced halocarbons in a double layer flow strait system , 1996 .

[17]  E. Özsoy,et al.  The evolution of Mediterranean water in the Black Sea: interior mixing and material transport by double diffusive intrusions , 1993 .

[18]  K. Johnson,et al.  Anthropogenic CO2 inventory of the Indian Ocean , 1999 .

[19]  J. Murray.  The 1988 Black Sea Oceanographic Expedition: introduction and summary , 1991 .

[20]  M. Khalil,et al.  The potential of soils as a sink of chlorofluorocarbons and other man-made chlorocarbons , 1989 .

[21]  E. Özsoy,et al.  Mixing on the Black Sea Shelf north of the Bosphorus , 1999 .

[22]  D. Tolmazin.  Changing coastal oceanography of the Black Sea II: Mediterranean effluent , 1985 .

[23]  E. Özsoy,et al.  Hydrographic properties and ventilation of the Black Sea , 1991 .

[24]  M. Stute,et al.  The use of 3H and tritiogenic 3He to determine CFC degradation and vertical mixing rates in Framvaren Fjord, Norway , 1997 .

[25]  R. Weiss,et al.  Solubilities of chlorofluorocarbons 11 and 12 in water and seawater , 1985 .

[26]  K. Buesseler,et al.  Mixing between oxic and anoxic waters of the Black Sea as traced by Chernobyl cesium isotopes. (Reannouncement with new availability information). Technical report , 1991 .

[27]  J. Murray,et al.  Black Sea oceanography , 1991 .

[28]  R. Weiss,et al.  Basin-wide distributions of chlorofluorocarbons CFC-11 and CFC-12 in the North Pacific: 1985–1989 , 1996 .

[29]  R. Weiss,et al.  Reconstructed histories of the annual mean atmospheric mole fractions for the halocarbons CFC‐11 CFC‐12, CFC‐113, and carbon tetrachloride , 2000 .

[30]  E. Özsoy,et al.  The Black Sea Cold Intermediate Layer , 1997 .

[31]  R. Weiss,et al.  Determination of CCl3F and CCl2F2 in seawater and air , 1988 .

[32]  R. Weiss,et al.  Atmospheric chlorofluoromethanes in the deep equatorial Atlantic , 1985, Nature.

[33]  Yu. N. Ryabtsev,et al.  Modelling of the generation and evolution of the cold intermediate layer in the Black Sea , 1996 .

[34]  D. Tolmazin,et al.  Changing Coastal oceanography of the Black Sea. I: Northwestern Shelf , 1985 .

[35]  D. Roemmich.  Optimal Estimation of Hydrographic Station Data and Derived Fields , 1983 .

[36]  J. Murray,et al.  Variations in the chemistry of the Black Sea on a time scale of decades (1960–1995) , 2001 .

[37]  W. Munk,et al.  Abyssal recipes II: energetics of tidal and wind mixing , 1998 .

[38]  F. Whitney,et al.  Chlorofluorocarbon CFC-11 and carbon tetrachloride removal in Saanich Inlet, an intermittently anoxic basin , 1999 .

[39]  Joan C. Woodward,et al.  Consumption of Freons CFC-11 and CFC-12 by anaerobic sediments and soils , 1992 .

[40]  G. Luther,et al.  Sulfur speciation and sulfide oxidation in the water column of the Black Sea , 1991 .

[41]  K. Buesseler,et al.  Plutonium oxidation states in the southwestern Black Sea: Evidence regarding the origin of the cold intermediate layer , 1991 .

[42]  Z. Top,et al.  Evidence of Tectonism from 3He and residence time of helium in the Black Sea , 1990 .

[43]  R. Weiss,et al.  Global trends and annual releases of CCl3F and CCl2F2 estimated from ALE/GAGE and other measurements from July 1978 to June 1991 , 1994 .

[44]  J. Murray.  Hydrographic Variability in the Black Sea , 1991 .

[45]  R. Weiss,et al.  A history of chemically and radiatively important gases in air deduced from ALE/GAGE/AGAGE , 2000 .