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clearly is too low. Because of low primary production, the standing stocks of zooplankton andbenthos are also low. WEIKERT (1982) gives figures of 2.7g wet weight m-2 for the zooplanktonstanding stock for the upper 104) m. To depths down to about 1000 m the standing stock resemblesthose found in other oligotrophic seas, such as the Mediterranean Sea and the central Pacific gyreregion (WEIKERT, 1982) (Fig. 3). However, the deeper waters throughout most of the Red Sea arealmost depleted of zooplankton, and, as a result, deep-sea benthos is also very sparse (Table 1) (seealso THIEL, 1979, 1981).The electron transport system activity (respiration potential) in sedimentcores from the Red Sea also shows low values (THEEG, 1985; THIEL et al., 1987). However,although respiration of total benthic communities is low, relative to benthic densities they are high.W e therefore have concluded that energy consumption for maintenance is relatively high, whereasless is available for production. W e have related this shift in the usage of energy in relation to thehigh environmental temperature, which is encountered by all organisms in the Red Sea. Comparableresults from the Atlantic and Arctic Oceans (PFANNKUCHE et al., 1983; THIEL and WEIKERT,1984; PFANNKUCHE and THIEL, 1987) support this hypothesis.+. Considering our results in an overall context suggests that the oligotrophic conditions of thecentral Red Sea are explained by low mixing rates in surface waters due to the unique meteorologicaland hydrographical settings. Mineralization of nutrients is enhanced by the high temperatures, butnutrient recycling is very slow. Primary production is limited by nutrient availability at low mixingrates, yet it occurs throughout the year. The accelerated degradation of organic matter in the watercolumn leaves little food for bathypelagic and bathybenthic species, which occur in unusually lownumbers and presumably have low productions. This short characterization from our results in thecentral Red Sea evidently is generally applicable to the entire Red Sea, with some local exceptions.OTHER RED SEA REGIONSThe strongest deviations from the results described for the central Red Sea are found in thesouthern regions, undoubtedly due to inflow of water from the Indian Ocean. Nutrient import seemsto be strongest during the summer months into the lower part of the euphotic zone (KHIMITSA andBIBIK, 1979; POISSON et al., 1984). As a result, nutrients can increase by up to 25% above levelsin the central Red Sea. This stimulates primary production by as much as 300% (compared to thedata of WEIKERT, 198 1 and KHMELEVA, 1970) and, subsequently, zooplankton standing stocksas much as 100% (BECKMANN, 1984). Water masses from the Gulf of Aden also transport livingand dead organic matter which fertilizes the southern Red Sea. As far north as 16'N BECKMANN(1984) found imported plankton from the Indian Ocean that was bound to die, as most species cannotwithstand the more severe conditions in the Red Sea. The higher production and the import oforganic matter are thought to be responsible for lower oxygen concentrations throughout the watercolumn of the southern Red Sea.North of the central region nutrients, primary production and standing stocks of zooplanktondecrease, whereas oxygen concentration increases, both in the surface and subsurface waters, due tolower temperatures and diminished degradation of organic matter. The decrease in nutrients appearsto be most pronounced in the phosphates. While 0.1-0.3 pmol l-1 were determined in the euphoticzone in the south, only 0.01-0.05 pmol 1-1 were found in the north. In the Gulf of Aqaba, recyclingof nutrients is achieved by vertical convection in the winter period, whereas during summer a strongthermocline stabilizes the water column (LEVANON-SPANIER et al., 1979). Consequently, theGulf exhibits a moderate primary production in winter that decreases with the formation of thethermocline (LEVANON-SPANIER et al., 1979). In contrast, the Gulf of Suez seems to be wellmixed from persistent winds so that a medium primary production might be expectedthroughout the year.According to SUKHANOVA (1969) and KHMELEVA (1970), primary production in thenorthern Red Sea may be half that in the central region. For the zooplankton, a similar decrease to thenorth is obtained from the data of DELALO (1966) and GORDEYEVA (1970). The ecologicalconsequences of predicted seasonal upwelling events in the farthest north, however, have not yetbeen investigated.300