Anthropogenic Impacts
409
to the reefs by oceanic currents, increase from year to year (Wood and
Johannes 1975; Marshalek 1981). They not only exert a toxic effect on reef
biota, but also foment some processes unusual for reef environment, such as
eutrophication (Walker and Ormond 1982). The nutrients accumulating on
the reef with wastewaters stimulate the growth of seaweeds, which inhibit
and toen replace the corals (Walker and Ormond 1982; Maragos et al. 1985;
Rasmussen and Cuff 1990). In areas subjected to discharge the blooming of
phytoplankton is furthered, including the toxic dinoflagellates and bluegreen algae (Banner 1974; Bell and Gabric 1991). These blooms violate
homeostatic conditions in reef ecosystems, thus destabilizing them. The
discharge of man-made wastewaters led to sulfate reduction and HzS
formation, which inhibit the bottom fauna and undermine the benthic
biofietering activity (Sorokin 1973c; Sorokin et al. 1982). The stimulation of
bacterioplankton growth by the pollution of reef waters improves the trophic
conditions for boring sponges, enhancing strongly their multiplication and
activities. They weaken the resistance of infested corals to surf and are the
cause of their mortaily (Rose and Risk 1985).
The waters discharged to reefs from the fields contain besides nutrient
fertilizers also pesticides, polychlorphenols, insecticides (delderin, eudrine),
and herbicides (high phenoxy acids). These substances accumulate in the
tissues of corals and other reef fauna, being toxic for them in concentrations
of 0.1 mg 1-1 (Glynn et al. 1984). In tissues of corals, which died in masses
on reefs off the west coast of Panama during the 1982-1983 El Nino (cf.
Sect. 7.3), pesticides were found (Glynn 1984). The local population has
been using in many of the reef regions the insecticides as poisons in fishery
(Endean 1976). Large amounts of detergents are dumped onto the reefs of
the GBR region by the sugar industry. These substances kill corals at a
concentration of 0.05%.
In reef areas numerous electricity and fresh-water producing plants were
installed serving cities touristic centers, and military bases. They discharge
warm waters with a high salinity, which kill corals at distances up to 1-2 km
(Johannes 1972b; Jokiel and Coles 1974). These discharges are especially
dangerous at high-latitude reefs, where corals are not adapted to high
temperature (Nudebecker 1981). The wastewates often contain chloramine,
used as an antifouling and antiseptic agent. It is poisonous to the bottom
fauna at a concentration of about 1 mg 1-1. Especially sensitive to this
poison are the larvae of bottom fauna (Best et al. 1981). Large amounts of
pesticides and antiseptics are discharged on reefs situated close to sea ports
(Loya 1976c). The industrial wastes and waste waters from mines bring
heavy metals to the reefs, e.g., copper, mercuty, and tin, which accumulate,
then in the tissues of corals and clams (Khristoforova et al. 1979; Fraizier et
al. 1985; Brown 1986; Brown and Wells 1989). Corals stressed so die or,
when they survive, they excrete a large quantitity of mucus. It stimulates
microbial growth, which then causes the mortality of corals (Mitchell and
Chet 1975). Often the mine waters contain much ammoniac, which is used
409
to the reefs by oceanic currents, increase from year to year (Wood and
Johannes 1975; Marshalek 1981). They not only exert a toxic effect on reef
biota, but also foment some processes unusual for reef environment, such as
eutrophication (Walker and Ormond 1982). The nutrients accumulating on
the reef with wastewaters stimulate the growth of seaweeds, which inhibit
and toen replace the corals (Walker and Ormond 1982; Maragos et al. 1985;
Rasmussen and Cuff 1990). In areas subjected to discharge the blooming of
phytoplankton is furthered, including the toxic dinoflagellates and bluegreen algae (Banner 1974; Bell and Gabric 1991). These blooms violate
homeostatic conditions in reef ecosystems, thus destabilizing them. The
discharge of man-made wastewaters led to sulfate reduction and HzS
formation, which inhibit the bottom fauna and undermine the benthic
biofietering activity (Sorokin 1973c; Sorokin et al. 1982). The stimulation of
bacterioplankton growth by the pollution of reef waters improves the trophic
conditions for boring sponges, enhancing strongly their multiplication and
activities. They weaken the resistance of infested corals to surf and are the
cause of their mortaily (Rose and Risk 1985).
The waters discharged to reefs from the fields contain besides nutrient
fertilizers also pesticides, polychlorphenols, insecticides (delderin, eudrine),
and herbicides (high phenoxy acids). These substances accumulate in the
tissues of corals and other reef fauna, being toxic for them in concentrations
of 0.1 mg 1-1 (Glynn et al. 1984). In tissues of corals, which died in masses
on reefs off the west coast of Panama during the 1982-1983 El Nino (cf.
Sect. 7.3), pesticides were found (Glynn 1984). The local population has
been using in many of the reef regions the insecticides as poisons in fishery
(Endean 1976). Large amounts of detergents are dumped onto the reefs of
the GBR region by the sugar industry. These substances kill corals at a
concentration of 0.05%.
In reef areas numerous electricity and fresh-water producing plants were
installed serving cities touristic centers, and military bases. They discharge
warm waters with a high salinity, which kill corals at distances up to 1-2 km
(Johannes 1972b; Jokiel and Coles 1974). These discharges are especially
dangerous at high-latitude reefs, where corals are not adapted to high
temperature (Nudebecker 1981). The wastewates often contain chloramine,
used as an antifouling and antiseptic agent. It is poisonous to the bottom
fauna at a concentration of about 1 mg 1-1. Especially sensitive to this
poison are the larvae of bottom fauna (Best et al. 1981). Large amounts of
pesticides and antiseptics are discharged on reefs situated close to sea ports
(Loya 1976c). The industrial wastes and waste waters from mines bring
heavy metals to the reefs, e.g., copper, mercuty, and tin, which accumulate,
then in the tissues of corals and clams (Khristoforova et al. 1979; Fraizier et
al. 1985; Brown 1986; Brown and Wells 1989). Corals stressed so die or,
when they survive, they excrete a large quantitity of mucus. It stimulates
microbial growth, which then causes the mortality of corals (Mitchell and
Chet 1975). Often the mine waters contain much ammoniac, which is used