ANTHROPOGENIC IMPACTS ON THE DEEP SEA
429
1989). As tracers, they should be non-reactive in
seawater, not metabolized by organisms, and not
adsorbed to particulate matter. This characterizes them
as perfect tracers, because they do not change their
concentrations with time and clearly mark their specific
water body. One such group of tracers are the socalled freons, the chlorofluorocarbons (CFCs)
1 , and
specifically F-11 (trichlorofluoromethane) and F-12
(dichlorofluoromethane). These substances are of anthropogenic origin and have been widely used as
refrigerants, aerosol propellants, blowing agents for
plastic foam, and solvents. They are volatile, and
considerable proportions enter the atmosphere after
their application. Transported into the stratosphere,
they are known to destroy ozone. In the oceans
they are carried with the water masses, so that their
continuing distribution can be demonstrated. Bullister
(1989) showed the distribution of F-12 in the North
Atlantic and its penetration into the deep sea. For the
South Atlantic he was able to trace the cold Weddell
Sea water into the deep sea to become the Weddell Sea
Bottom Water below 4000 m. The southward flow of
deep Arctic Ocean water along the western Fram Strait,
through the Greenland Sea and the Denmark Strait into
the North Atlantic was studied by Smethie et al. (1988)
using F-11 and F-12.
Doney and Bullister (1992) and Smethie (1993)
have shown that chlorofluorocarbons penetrated more
deeply into the western than into the eastern North
Atlantic, which is in accordance with the known fact
that the deep-sea water masses are formed in the
western part of this ocean. For the deep sea of the
Eastern Mediterranean, Schlitzer et al. (1991) were able
to demonstrate with the help of chlorofluorocarbons
that the source of bottom and deep waters is the
Adriatic Sea, and Rhein (1996) described the processes
of deep-water formation in the Greenland Sea by
studying the distribution of chlorofluorocarbons. This
water mass carries the contaminants into the deep
North Atlantic and finally throughout the world ocean,
as has been graphically described by Broecker (1991)
in his postulated inter-oceanic conveyor-belt system.
S¨ ultenfuß (1998) has presented results on the distribution of F-11, together with tritium, in the Weddell
Sea, and demonstrated higher levels in surface, slope
and bottom waters down to 5000 m depth compared
to the open water column. The ratios of different
chlorofluorocarbons in a water body provide true
markers for water masses, and it was shown that
surprisingly little mixing occurs in the interior of the
ocean. Other useful tracers are, for example, helium
isotopes, tritium and neon (e.g., Roether et al., 1996).
Organochlorine and organotin compounds
Another class of man-made substances found in the
oceans are the synthetic organochlorine compounds,
including the polychlorinated biphenyls (PCBs), the
hexachlorocyclohexanes (HCHs), trichlorethane (DDT)
and its metabolites, and the polychlorinated camphenes (PCCs). Their physicochemical properties show
a broad range in respect of water solubility, vapour
pressure, biodegradability, lipophilicity and particle
affinity. In recent years it has been demonstrated
that low-volatility organochlorine compounds are distributed by atmospheric transport from tropical and
temperate to polar regions (Duce et al., 1991; Wania
and Mackay, 1993; Iwata et al., 1993; Loganathan
and Kannan, 1994; and literature cited therein). These
substances have been discovered in relatively high
concentrations in the Arctic and Antarctic Oceans,
in various terrestrial and marine biota, and also in
human populations of the high-arctic region. They
have been traced from warmer localities at lower
latitudes to cold environments at higher latitudes, where
they precipitate with rain or snow after condensation
(Hargrave et al., 1988; Patton et al., 1989; Oehme,
1991; Arctic Monitoring and Assessment Programme,
1998).
Since the renewal process of the deep-ocean water masses starts at the surface in polar regions,
contaminants are likely to be transported into and
widely dispersed in the deep sea, as shown above
for radionuclides and chlorofluorocarbons. The existence of organochlorines in the deep sea has been
described by Tanabe and Tatsukawa (1983), Knap et al.
(1986), Schulz et al. (1988), Fischer et al. (1991)
and Ballschmiter et al. (1997), but no impacts were
observed.
In shallow waters, metabolites of some persistent
organochlorines and detergent components were found
to act as oestrogenic chemicals even at low concentrations, adversely affecting male and female gonads and
the development of reproductive tracts (e.g., Jobling
and Sumpter, 1993; Kelce et al., 1995; Ruiz et al.,
1996; Colborn et al., 1996; Ide et al., 1997). Nothing of
1 For a list of acronyms see the appendix on p. 471.
429
1989). As tracers, they should be non-reactive in
seawater, not metabolized by organisms, and not
adsorbed to particulate matter. This characterizes them
as perfect tracers, because they do not change their
concentrations with time and clearly mark their specific
water body. One such group of tracers are the socalled freons, the chlorofluorocarbons (CFCs)
1 , and
specifically F-11 (trichlorofluoromethane) and F-12
(dichlorofluoromethane). These substances are of anthropogenic origin and have been widely used as
refrigerants, aerosol propellants, blowing agents for
plastic foam, and solvents. They are volatile, and
considerable proportions enter the atmosphere after
their application. Transported into the stratosphere,
they are known to destroy ozone. In the oceans
they are carried with the water masses, so that their
continuing distribution can be demonstrated. Bullister
(1989) showed the distribution of F-12 in the North
Atlantic and its penetration into the deep sea. For the
South Atlantic he was able to trace the cold Weddell
Sea water into the deep sea to become the Weddell Sea
Bottom Water below 4000 m. The southward flow of
deep Arctic Ocean water along the western Fram Strait,
through the Greenland Sea and the Denmark Strait into
the North Atlantic was studied by Smethie et al. (1988)
using F-11 and F-12.
Doney and Bullister (1992) and Smethie (1993)
have shown that chlorofluorocarbons penetrated more
deeply into the western than into the eastern North
Atlantic, which is in accordance with the known fact
that the deep-sea water masses are formed in the
western part of this ocean. For the deep sea of the
Eastern Mediterranean, Schlitzer et al. (1991) were able
to demonstrate with the help of chlorofluorocarbons
that the source of bottom and deep waters is the
Adriatic Sea, and Rhein (1996) described the processes
of deep-water formation in the Greenland Sea by
studying the distribution of chlorofluorocarbons. This
water mass carries the contaminants into the deep
North Atlantic and finally throughout the world ocean,
as has been graphically described by Broecker (1991)
in his postulated inter-oceanic conveyor-belt system.
S¨ ultenfuß (1998) has presented results on the distribution of F-11, together with tritium, in the Weddell
Sea, and demonstrated higher levels in surface, slope
and bottom waters down to 5000 m depth compared
to the open water column. The ratios of different
chlorofluorocarbons in a water body provide true
markers for water masses, and it was shown that
surprisingly little mixing occurs in the interior of the
ocean. Other useful tracers are, for example, helium
isotopes, tritium and neon (e.g., Roether et al., 1996).
Organochlorine and organotin compounds
Another class of man-made substances found in the
oceans are the synthetic organochlorine compounds,
including the polychlorinated biphenyls (PCBs), the
hexachlorocyclohexanes (HCHs), trichlorethane (DDT)
and its metabolites, and the polychlorinated camphenes (PCCs). Their physicochemical properties show
a broad range in respect of water solubility, vapour
pressure, biodegradability, lipophilicity and particle
affinity. In recent years it has been demonstrated
that low-volatility organochlorine compounds are distributed by atmospheric transport from tropical and
temperate to polar regions (Duce et al., 1991; Wania
and Mackay, 1993; Iwata et al., 1993; Loganathan
and Kannan, 1994; and literature cited therein). These
substances have been discovered in relatively high
concentrations in the Arctic and Antarctic Oceans,
in various terrestrial and marine biota, and also in
human populations of the high-arctic region. They
have been traced from warmer localities at lower
latitudes to cold environments at higher latitudes, where
they precipitate with rain or snow after condensation
(Hargrave et al., 1988; Patton et al., 1989; Oehme,
1991; Arctic Monitoring and Assessment Programme,
1998).
Since the renewal process of the deep-ocean water masses starts at the surface in polar regions,
contaminants are likely to be transported into and
widely dispersed in the deep sea, as shown above
for radionuclides and chlorofluorocarbons. The existence of organochlorines in the deep sea has been
described by Tanabe and Tatsukawa (1983), Knap et al.
(1986), Schulz et al. (1988), Fischer et al. (1991)
and Ballschmiter et al. (1997), but no impacts were
observed.
In shallow waters, metabolites of some persistent
organochlorines and detergent components were found
to act as oestrogenic chemicals even at low concentrations, adversely affecting male and female gonads and
the development of reproductive tracts (e.g., Jobling
and Sumpter, 1993; Kelce et al., 1995; Ruiz et al.,
1996; Colborn et al., 1996; Ide et al., 1997). Nothing of
1 For a list of acronyms see the appendix on p. 471.