139736eo.pdf (20MB) - Japan Oceanographic Data Center

Benthic studies in the deep waters have not demonstrated latitudinal differences in the RedSea, although it is known that deep benthos standing stocks should mirror surface water productivity.No explanation is available for these observations. The low values for benthic standing stocks,together with a variability in faunal. densities and in sedimentary conditions, may obscure existentdifferences. However, MURINA (197 1) described a north-south increase of benthic standing stocksfrom samples mainly collected along the narrow shelf, i.e., in depths close to the epipelagic zone.Summarizing the data, she found benthic biomasses in the south to be four times those in the north.PROPOSED RESEARCHOur limited knowledge allows us to draw only a general picture of the oceanic system in theRed Sea. However, we must bear in mind that the Red Sea basin contains a unique environment andresultant biocoenoses as determined by the basin's size (compared to other oceans), young geologicalage, isolation from the Indian Ocean, hydrography, and biology.The characteristics and adaptations within the Red Sea are worthy of study on their own rightbut also for comparisons with other oceans. Cooperative oceanographic investigations using the RedSea as a tropical ocean ecosystem model can help us describe and understand the world ocean. Forexample, relative to other warm seas, this basin obviously has a less complex pelagic and benthicsystem, since diversity in the zooplankton, micronekton and benthos seems to be strongly reduced.Within such a broad context we propose that long-term studies be initiated from severalresearch institutions along the Red Sea coasts (and Indian Ocean), applying intercalibrated methods.We suggest the following topics:- assessment of primary production throughout the year, including specific observations onthe ecologically important Cyanobacteria (Osciffutoria) blooms.- assessment of zooplankton production (different size classes) and micronekton, based ontotal standing stock and biomass and on population studies. The demographic andgenetic consequences of the import of Gulf of Aden species' to the Red Sea needs to beconsidered. In this context, species reproductive capacities in different geographicregions, their depth distribution and vertical migrations are of particular interest.- assessment of benthic production, taking into account algae, corals and other animalsfrom the shelf and in deeper regions.- assessment of organic matter transport between coral reefs (shelf) and oceanic regions.- assessment of brine-influenced benthic communities in the deep Red Sea.Many of the pertinent questions, basic or applied, can be combined fruitfully in commonresearch programmes.REFERENCESBECKMANN, W. (1984). Mesozooplankton distribution on a transect from the Gulf of Aden to thecentral Red Sea during the winter monsoon. Oceanol. Acta 7,87-102.DELALO, E.P. (1966). Distribution of the zooplankton biomass in the Red Sea and Gulf of Aden,winter 1961/62 (in Russian). Okeanologicheskiye issled., 15, 131-139.DOWIDAR, N.M. (1983). Primary production in the central Red Sea off Jeddah. Bull. Inst.Oceanogr. Fish., 9, 171-178.GORDEYEVA, K.T. (1970). Quantitative distribution of zooplankton in the Red Sea. Oceanology,10, 867-871.HALIM, Y. (1984). Plankton of the Red Sea and the Arabian Gulf. Deep-sea Res., 3 1,969-982.301