Abstract
Abundance of the eelgrass Zostera marina L. was studied in a coastal lagoon in southern California (USA), and was found to correlate with the level of irradiance at depths greater than 0.5 m below tidal datum. Results of controlled field experiments, using canopies to reduce downwelling illuminance by 63%, confirmed that turion density is a function of the irradiance the plants receive. By Day 18 of the experiment, turion density in the shaded experimental areas had decreased compared to the density of adjacent unshaded controls. Turion densities were continually lower throughout the 9-month study in the experimental areas, which at the end of the study had a turion density only 5% that of the control areas. Flowering in the experimental areas was also inhibited by shading. The biological implications of these findings are discussed with respect to seasonal changes in incident solar radiation, water transparency, and changes in water quality due to man's increased intervention in the natural processes of coastal lagoons.
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Literature Cited
Addicott, F. T. and J. L. Lyon: Physiological ecology of abscission. In: Shedding of plant parts, pp 85–124. Ed. by T. T. Kozlowski. New York: Academic Press 1973
Bradshaw, J. and G. Estberg: An ecological study of the subtidal marine life of Agua Hedionda Lagoon, Part 1. 145 pp. University of San Diego 1972
Bliss, C. I.: Statistics in biology, Vol. 1. 558 pp. New York: McGraw-Hill Book Co. 1967
Burkholder, P.R. and T.E. Doheny: The biology of eelgrass. Contr. Dep. Conserv. Waterways, Town of Hempstead, Long Island, N.Y. 3, 1–120 (1968)
Coleman, D.C. and R.G. Weigert: A simple, inexpensive temperature integrator. Bioscience 17, 481–482 (1967)
Conover, J.T.: The importance of natural diffusion gradients and transport of substrate to benthic marine metabolism. Botanica mar. 11, 1–19 (1968)
Emery, K.O.: The sea off southern California, 366 pp. New York: John Wiley 1960
Hardwick, J.E.: Biomass estimates of spawning herring Clupea harengus pallasi, herring eggs, and associated vegetation in Tomales Bay. Calif. Fish Game 59, 36–61 (1973)
Holmes, R.W.: The Secchi disk in turbid coastal waters. Limnol. Oceanogr. 15, 688–694 (1970)
Idso, S.B. and R.G. Gilbert: On the universality of the Poole and Atkins Secchi disk-light extinction equation. J. appl. Ecol. 11, 399–401 (1974)
Keller, M. and S.W. Harris: The growth of eelgrass in relation to tidal depth. J. Wildl. Mgmt 30, 280–285 (1966)
McRoy, C.P.: Standing stocks and other features of eelgrass (Zostera marina L.) populations on the coast of Alaska. J. Fish Res. Bd Can. 27, 1811–1821 (1970)
— Seagrass productivity: carbon uptake experiments in eelgrass, Zostera marina. Aquaculture 4, 131–137 (1974)
—, R.J. Barsdate and N. Nebert: Phosphate cycling in an eelgrass (Zostera marina L.) ecosystem. Limnol. Oceanogr. 17, 58–67 (1972)
— and R.C. Phillips: Supplementary bibliography on eelgrass Zostera marina. Spec. scient. Rep. U.S. Fish Wild. Serv. 14, 258–269 (1973)
Ostenfeld, C.H.: Preliminary remarks on the distribution and biology of the Zostera of the Danish seas. Bot. Tidsskr. 27, 123–125 (1905)
Phillips, R.C.: Comprehensive bibliography of Zostera marina. Spec. scient. Rep. U.S. Fish Wildl. Serv. 79, 1–35 (1964)
Phillips, R.C.: Ecological life history of Zostera marina L. (eelgrass) in Puget Sound, Washington. Ph.D. dissertation, Seattle, University of Washington 1972
Pokonry, K.: Labyrinthula. J. Protozool. 14, 697–708 (1967)
Sculthorpe, C.D.: The biology of aquatic vascular plants, 610 pp. London: Edward Arnold Publishers Ltd. 1967
Setchell, W.A.: Morphological and phenological notes on Zostera marina L. Univ. Calif. Publs Bot. 14, 389–452 (1929)
Smith, R.C.: An underwater spectral irradiance collector. J. mar. Res. 27, 341–351 (1969)
Tutin, T.G.: The autecology of Zostera marina in relation to its wasting disease. New Phytol. 37, 50–71 (1938)
— Zostera. J. Ecol. 30, 217–226 (1942)
U.S. Department of Commerce: Climatic atlas of the United States, 80 pp. Washington, D.C.: Government Printing Office 1968
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Communicated by J. S. Pearse, Santa Cruz
Contribution No. 4 from the Center for Marine Studies, San Diego State University, San Diego, California 92182, USA.
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Backman, T.W., Barilotti, D.C. Irradiance reduction: Effects on standing crops of the eelgrass Zostera marina in a coastal lagoon. Mar. Biol. 34, 33–40 (1976). https://doi.org/10.1007/BF00390785
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DOI: https://doi.org/10.1007/BF00390785