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Effect of discharge on the chlorophyll a distribution in the tidally-influenced Potomac River
OLR (1987) 34 (9)
E. Biological Oceanography
benthic assemblages is concentrated in the larger sized classes. We postulate that these differences result, in part, from differences in the quality and quantity of available organic matter. Most of the labile organic matter that reaches the deep-sea bottom is consumed at or near the sediment-water interface. Transformation of refractory organic matter into utilizable substrate by sediment bacteria and bioturbation aid the transfer of recently deposited organic matter to subsurface deposit feeders. NATO SACLANT ASW Res. Centre, Viale San Bartolomeo 400, I 19026 La Spezia, Italy. 87:5161 Thurston, M.H., D.S.M. Billett and Elizabeth Hassack, 1987. An association between Exspina typica Lang (Tanaldacea) and deep-sea holothurians. J. mar. biol. Ass. U.K., 67(1):11-15. First reports of the association between Exspina typica and three species of abyssal holothurian are presented. These records suggest that the association is a real one, and not an artefact sampling, but throw no light on the nature of the association. The geographic and bathymetric distribution of E. typica are summarized. Inst. of Oceanogr. Sci., Brook Rd., Wormley, Godalming, Surrey GU8 5UB, UK. 87:5162 Tomascik, T. and F. Sander, 1987. Effects of eutrophication on reef-building corals. II. Structure of scleractinian coral communities on fringing reefs, Barbados, West Indies. Mar. Biol., 94(1):53-75. The structure of scleractinian coral communities was studied along an eutrophication gradient with a quantitative sampling method (line transect) in terms of species composition, zonation and diversity patterns. On the basis of these data the fringing reefs were divided into three ecological zones: back reef, reef flat, and spur and groove. High correlations between environmental variables and biotic patterns indicate that the effects of eutrophication processes (nutrient enrichment, sedimentation, turbidity, toxicity and bacterial activity) were directly and/or indirectly affecting the community structure. It is suggested that sediment rejection abilities, combined with feeding and reproductive strategies, are the primary biological processes of scleractinian corals through which eutrophication affects the structure of coral communities. Bellairs Res. Inst. of McGill Univ., St. James, Barbados, West Indies. 87:5163 Tomascik, T. and F. Sander, 1987. Effects of eutrophication on reef-building corals. III. Re-
777
production of the reef-building coral Porites porites. Mar. Biol., 94(1):77-94. The sexual reproduction of Porites porites was studied over a one-year period on three fringing reef complexes lying along an eutrophication gradient on the west coast of Barbados, West Indies. The data suggest that P. porites is a gonochoric species with a brooding mode of reproduction, but a low incidence (2.7%) of hermaphroditism was detected in a population sampled from a reef subjected to urban and industrial pollution. The reproductive season of populations sampled from two polluted reefs began one to two months earlier than that of a P. porites population sampled from a less polluted reef. The reduction of zooxanthellae photosynthesis through reduced light levels may significantly lower the energy available from photosynthates to the maturing ova and/or embryos, thus depressing larval development and maturation. Coral colonies sampled from two polluted reefs contained lower numbers of larvae than colonies from a less polluted reef. The 2:1 sex ratio observed in a P. porites population sampled from a polluted reef may result from rapid asexual reproduction indicating that the mode of reproduction may be influenced by environmental conditions. Bellairs Res. Inst. of McGill Univ., St. James, Barbados, West Indies.
El20. Estuarine, marsh and mangrove communities 87:5164 Alongi, D.M., 1987. The influence of mangrovederived tannins on intertidal meiobenthos in tropical estuaries. Oecologia, 71(4):537-540. Australian Inst. of Mar. Sci., PMB No. 3, Townsville, M.C., Qld. 4810, Australia.
87:5165 Bennett, J.P., J.W. Woodward and D.J. Shultz, 1986. Effect of discharge on the chlorophyll a distribution in the tidally-influenced Potomac River. Estuaries, 9(4A):250-260. USGS, 12201 Sunrise Valley Dr., Reston, VA 22092, USA. 87:5166 Lewis, F.G. III, 1987. Crustacean epifauna of seagrass and macroalgae in Apainehee Bay, Florida, USA. Mar. Biol., 94(2):219-229. Office of Coastal Mgmt., Dept. of Environ. Regulation, 2600 Blairstone Rd., Tallahassee, FL 32301, USA.
E. Biological Oceanography
benthic assemblages is concentrated in the larger sized classes. We postulate that these differences result, in part, from differences in the quality and quantity of available organic matter. Most of the labile organic matter that reaches the deep-sea bottom is consumed at or near the sediment-water interface. Transformation of refractory organic matter into utilizable substrate by sediment bacteria and bioturbation aid the transfer of recently deposited organic matter to subsurface deposit feeders. NATO SACLANT ASW Res. Centre, Viale San Bartolomeo 400, I 19026 La Spezia, Italy. 87:5161 Thurston, M.H., D.S.M. Billett and Elizabeth Hassack, 1987. An association between Exspina typica Lang (Tanaldacea) and deep-sea holothurians. J. mar. biol. Ass. U.K., 67(1):11-15. First reports of the association between Exspina typica and three species of abyssal holothurian are presented. These records suggest that the association is a real one, and not an artefact sampling, but throw no light on the nature of the association. The geographic and bathymetric distribution of E. typica are summarized. Inst. of Oceanogr. Sci., Brook Rd., Wormley, Godalming, Surrey GU8 5UB, UK. 87:5162 Tomascik, T. and F. Sander, 1987. Effects of eutrophication on reef-building corals. II. Structure of scleractinian coral communities on fringing reefs, Barbados, West Indies. Mar. Biol., 94(1):53-75. The structure of scleractinian coral communities was studied along an eutrophication gradient with a quantitative sampling method (line transect) in terms of species composition, zonation and diversity patterns. On the basis of these data the fringing reefs were divided into three ecological zones: back reef, reef flat, and spur and groove. High correlations between environmental variables and biotic patterns indicate that the effects of eutrophication processes (nutrient enrichment, sedimentation, turbidity, toxicity and bacterial activity) were directly and/or indirectly affecting the community structure. It is suggested that sediment rejection abilities, combined with feeding and reproductive strategies, are the primary biological processes of scleractinian corals through which eutrophication affects the structure of coral communities. Bellairs Res. Inst. of McGill Univ., St. James, Barbados, West Indies. 87:5163 Tomascik, T. and F. Sander, 1987. Effects of eutrophication on reef-building corals. III. Re-
777
production of the reef-building coral Porites porites. Mar. Biol., 94(1):77-94. The sexual reproduction of Porites porites was studied over a one-year period on three fringing reef complexes lying along an eutrophication gradient on the west coast of Barbados, West Indies. The data suggest that P. porites is a gonochoric species with a brooding mode of reproduction, but a low incidence (2.7%) of hermaphroditism was detected in a population sampled from a reef subjected to urban and industrial pollution. The reproductive season of populations sampled from two polluted reefs began one to two months earlier than that of a P. porites population sampled from a less polluted reef. The reduction of zooxanthellae photosynthesis through reduced light levels may significantly lower the energy available from photosynthates to the maturing ova and/or embryos, thus depressing larval development and maturation. Coral colonies sampled from two polluted reefs contained lower numbers of larvae than colonies from a less polluted reef. The 2:1 sex ratio observed in a P. porites population sampled from a polluted reef may result from rapid asexual reproduction indicating that the mode of reproduction may be influenced by environmental conditions. Bellairs Res. Inst. of McGill Univ., St. James, Barbados, West Indies.
El20. Estuarine, marsh and mangrove communities 87:5164 Alongi, D.M., 1987. The influence of mangrovederived tannins on intertidal meiobenthos in tropical estuaries. Oecologia, 71(4):537-540. Australian Inst. of Mar. Sci., PMB No. 3, Townsville, M.C., Qld. 4810, Australia.
87:5165 Bennett, J.P., J.W. Woodward and D.J. Shultz, 1986. Effect of discharge on the chlorophyll a distribution in the tidally-influenced Potomac River. Estuaries, 9(4A):250-260. USGS, 12201 Sunrise Valley Dr., Reston, VA 22092, USA. 87:5166 Lewis, F.G. III, 1987. Crustacean epifauna of seagrass and macroalgae in Apainehee Bay, Florida, USA. Mar. Biol., 94(2):219-229. Office of Coastal Mgmt., Dept. of Environ. Regulation, 2600 Blairstone Rd., Tallahassee, FL 32301, USA.