1068 E. Biological Oceanograph3, OLR 11987134 (12)

rigida extracts deterred feeding at pellet concen- trations less than an order of magnitude lower than those found in the soft tissue of corresponding gorgonians. The data support the hypothesis that the soft tissues of many gorgonian corals contain lipid-soluble feeding deterrents. Fenical: Scripps Inst. of Oceanogr., La Jolla, CA 92093, USA.

87:6985 Sano, Mitsuhiko, Makoto Shimizu and Yukio Nose,

1987. Long-term effects of destruction of her- matypic corals by Acanthaster planci Infestation on reef fish commlmltieS at lriomote Island, Japan. Mar. Ecol.-Prog. Ser., 37(2-3):191-199.

Long-term structural changes in fish communities on coral reefs infested by the coral-feeding starfish .4. planci were determined. A living coral reef consisting mainly of staghorn, and a dead reef with low structural complexity of branches (about 2 yr after infestation) were examined. Two years later the dead reef, now flat coral rubble, was re-examined. Coral- polyp feeders had disappeared on both dead rubble reefs. Resident species and individuals decreased on the dead reef, perhaps due to reduction in shelter, and declined severely on the rubble reef, likely due to lack of living space and food. Dept. of Fish., Univ. of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113, Japan.

87:6986 Wilkinson, C.R., 1987. Interoceam differences in size

and nutrition of coral reef sponge populations. Science, 236(4809):1654-1656.

Sponges consume an order of magnitude more organic matter on Caribbean coral reefs than on the Great Barrier Reef. This rate of consumption is attributed to Caribbean sponge biomass being five to six times greater than that on the Great Barrier Reef, and to the absence in the Caribbean of phototrophic sponges. The long temporal and spatial separation of the Atlantic and Pacific oceans has resulted in the evolution of dissimilar sponge faunas, with Car- ibbean sponges being heterotrophic, whereas many Great Barrier Reef sponges rely on nutritional input from photosynthetic symbionts. ©1987 by AAAS. Australian Inst. of Mar. Sci., PMB No. 3, Townsville MC, Qld. 4810, Australia.

El20. Estuarine, marsh and mangrove communities

87:6987 Dawson, T.E. and L.C. Bliss, 1987. Species patterns,

edaphic characteristics, and plant water patentlml

in a high-erctic brackish marsh. Can. J. Bot., 65(5):863-868.

Small marshes on the northeast coast of Devon Island are dominated by distinct zones of Puccinellia phryganodes nearest the sea with Carex ursina, C. stans, Dupontia fisheri, and Alopecurus alpinus dom- inated zones landward. Soil salinity and chloride ion content increase seaward, but plant water potential becomes less negative, opposite to the expected pattern. Fresh water from melting pack ice forms a lens over the more dense seawater, diluting salts in the upper soil layer, and creating a low salinity condition for plants that inhabit zones nearest the sea. Apparently it is this 'fresh' water that comes into contact with the roots of Puccinellia and Carex ursina, thus maintaining less-negative water poten- tials in these species. Plant zonation can be ex- plained in part by such considerations, but edaphic characteristics are not the only factors involved. Dept. of Botany, Univ. of Washington, Seattle, WA 98195, USA.

87:6988 Harrison, P.G., 1987. Natural expansion and exper-

imental manipulation of seagrass (Zostera spp.) abundance and the response of infaunal inver- tebrates. Estuar. coast. Shelf Sci., 24(6):799-812.

The expansion of a Zostera marina bed and Z. japonica colonization following cut-off of silty riverine input was documented along with the impact on burrowing shrimp (Callianassa cali- forniensis). Z. japonica colonization at the landward edge of the expanding Z. marina bed was followed by increased expansion. Shrimp abundance de- creased in the colonized areas and removal exper- iments showed that shrimp axad tube worms were able to recolonize the sediment. Subsequent trans- planting caused a temporary decrease in shrimp numbers, but an established shrimp population was able to destroy transplants in a few weeks. Dept. of Botany, Univ. of British Columbia, Vancouver, BC V6T 2B1, Canada. (gsb)

El30. Fouling and boring organisms (communities and control)

87:6969 Daniel, G.F., A.H.L. Chamberlain and E.B.G.

Jones, 1987. Cytoeheml¢81 and electron micro- scoplcal observations on the adhesive materials of marine fonl~g db~mms. Br. phycol. J., 22(2):101- 118. Inst. for Virkeslara, Sveriges, Lantbruk- suniversitet, Box 7008, S-750 07, Uppsala, Sweden.