Abstract
Inshore-offshore transects and time-series sampling programs were carried out on the South shore of the St. Lawrence Estuary on several occasions during the summer season of 1978, 1979 and 1986. In 1981, a time-series sampling program was also conducted on three occasions during the summer. The sampling program was carried out to test the hypothesis that higher phytoplankton biomass and productivity occurs in the littoral zone than in the offshore zone. Our results showed consistently higher nutrient concentrations and lower seasonal variability in the littoral zone than offshore. However, biomass indicators (chlorophyll concentrations and phytoplankton cell counts) showed lower values nearshore than offshore, in contrast to primary production and photosynthetic capacity which were higher nearshore than offshore. These differences are interpreted with reference to the grazing activity of benthic filter-feeders, which probably helped to reduce the phytoplankton biomass in the littoral zone, while at the same time, they contributed to the rapid recycling of nutrients, thereby allowing much higher phytoplankton productivity nearshore than offshore. These results are in keeping with the ecological concept suggesting that exploitation can have a rejuvenating effect on an ecosystem which often is translated into enhanced productivity.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
Literature cited
Cota, G. F. C. (1985). Photoadaptation of high arctic ice algae. Nature, Lond. 315: 219–222
Dame, R., Zingmark, R., Stevenson, H., Nelson, D. (1980). Filter feeder coupling between estuarine water column and benthic subsystems. In: Kennedy, V.S. (ed) Estuarine perspectives. Academic Press, New York, p. 521–526
Demers, S., Legendre, L. (1979). Effects des marées sur la variation circadienne de la capacité photosynthétique du phytoplancton de l'estuaire du Saint-Laurent. J. exp. mar. Biol. Ecol. 39: 87–99
Demers, S., Legendre, L. (1981). Mélange vertical et capacité photosynthétique du phytoplancton estuarien (estuaire du Saint-Laurent). Mar. Biol. 64: 243–250
Demers, S., Legendre, L. (1982). Water column stability and photosynthetic capacity of estuarine phytoplankton: long-term relationships. Mar. Ecol. Prog. Ser. 7: 337–340
Demers, S., Legendre, L., Therriault, J. C. (1986). Phytoplankton responses to vertical tidal mixing. In: Bowman, J., Yentsch, C. M., Peterson, W. T. (eds.) Tidal mixing and plankton dynamics. Springer-Verlag, Berlin Heidelberg, p. 1–40
Demers, S., Therriault, J. C., Bourget, E., Bah, A. (1987). Resuspension in the shallow littoral zone of a macrotidal estuarine environment: wind influence. Limnol. Oceanogr. 32: 327–339
Doty, M. S., Oguri, M. (1959). The carbon-fourteen technique for determining primary plankton productivity. Pubbl. Staz. zool. Napoli 31 (Suppl.): 70–94
Falkowski, P. G. (1980). Light and shade adaptation in marine phytoplankton. In: Falkowski, P. G. (ed.) Primary productivity in the sea. Plenum Press, New York, p. 99–119
Falkowski, P. G. (1984). Kinetics of adaptation to irradiance in Dunaliella tertiolecta, Photosynthetica 18: 62–68
Fortier, L., Legendre, L. (1979). Le contrôle de la variabilité à court terme du phytoplancton: stabilité verticale et profondeur critique. J. Fish. Res. Bd. Can. 36: 1325–1335
Fréchette, M. (1984). Interactions pélago-benthiques et flux d'énergie dans une population de moules bleues, Mytilus edulis L., de l'estuaire du Saint-Laurent. Ph.D. thesis. Université Laval, Québec.
Fréchette, M., Bourget, E. (1985a). Energy flow between the Pelagic and Benthic zones: Factors controlling particulate organic matter available to an intertidal mussel bed. Can. J. Fish. aquat. Sciences 42: 1158–1165
Fréchette, M., Bourget, E. (1985b). Food-limited growth of Mytilus edulis L. in relation to the benthic boundary layer. Can. J. Fish. aquat. Sciences 42: 1166–1170
Fréchette M., Legendre, L. (1982). Phytoplankton photosynthetic response to light in an internal tide dominated environment. Estuaries, 5: 287–293
Gosselin, M., Legendre, L., Demers, S., Ingram, R. G. (1985). Responses of sea-ice microalgae to climatic and fortnightly tidal energy inputs (Manitounuk Sound, Hudson Bay), Can. J. Fish. aquat. Sciences 42: 999–1006
Holmes, R. W. (1970). The Secchi disk in turbid coastal waters. Limnol. Oceanogr. 15: 688–694
Holm-Hansen, O., Riemann, B. (1978). Chlorophyll a determination: improvements in methodology. Oikos 30: 438–447
Legendre, L. (1981). Hydrodynamic control of marine phytoplankton production: the paradox of stability. In: Nihoul, J.C.J. (ed.) Ecohydrodynamics. Elsevier, Amsterdam, p. 181–207
Legendre, L., Demers, S. (1985). Auxiliary energy, ergoclines and aquatic biological production. Naturaliste can. (Rev. Ecol. Syst.) 112: 5–14
Legendre, L., Demers, S., Lefaivre, D. (1986). Biological production at marine ergoclines. In: Nihoul, J. C. J. (ed.) Marine interfaces ecohydrodynamics. Elsevier, Amsterdam. p. 1–29
Lewis, M. R., Smith, J. C. (1983). A small volume, short-incubation-time method for measurement of photosynthesis as a function of incident irradiance. Mar. Ecol. Prog. Ser. 13: 99–102
Lund, J. W. G., Kipling, C., Lecren, E. D. (1958). The inverted microscope method of estimating algal numbers and the statistical basis of estimations by counting. Hydrobiologia 11: 143–170
Margalef, R. (1963). On certain unifying principles in ecology. Am. Nat. 97: 357–374
Margalef, R. (1967). Some concepts relative to the organization of plankton. Oceanogr. mar. Biol. A. Rev. 5: 257–289
Margalef, R. (1978). What is an upwelling ecosystem? In: Boje R., Tomczak, M. (eds.) Upwelling ecosystem. Springer-Verlag, Berlin. p. 12–14
Odum, E. P. (1969). The strategy of ecosystem development. Science, N.Y. 164: 262–269
Odum, E. P. (1980). The status of three ecosystem level hypotheses regarding salt-marsh estuary: tidal subsidy, outwelling, and detritus based food chains. In: Kennedy, V. S. (ed.), Estuarine perspectives. Academic Press, New York, p. 485–495
Odum, E. P., Finn, J. T., Franz, E. H. (1979). Perturbation theory and the subsidy-stress gradient. BioSci. 29: 349–352
Pingree, R. D. (1978). Mixing and stabilization of phytoplankton distributions on the Northwest European continental shelf. In: Steele, J. M. (ed.) Spatial pattern in plankton communities. Plenum Press, New York, p. 181–200
Platt, T., Gallegos, C. L., Harrison, W. G. (1980) Photoinhibition of photosynthesis in natural assemblages of marine phytoplankton. J. mar. Res. 38: 687–701
Pugh, P. R. (1973). An evaluation of liquid scintillation counting techniques for use in aquatic primary production studies. Limnol. Oceanogr. 18: 310–319
Savidge, G. (1979). Photosynthetic characteristics of marine phytoplankton from contrasting physical environments. Mar. Biol. 53: 1–12
Steever, E. Z., Warren, R. S., Niering, W. A. (1976). Tidal energy subsidy and standing crop production of Spartina alterniflora. Estuarine coastal Mar. Sci. 4: 473–478
Strickland, J. D., Parsons, T. R. (1972). A practical handbook of seawater analyses. Bull. Fish. Res. Bd Can. 167: p. 310
Therriault, J. C., Levasseur, M. (1985). Control of phytoplankton production in the lower St. Lawrence estuary: light and freshwater runoff. Naturaliste can. (Rey. Ecol. Syst.) 112: 77–96
Webb, K. L., D'Elia, C. F. (1980). Nutrient and oxygen redistribution during a spring neap tidal cycle in a temperate estuary. Science, N.Y. 207: 983–985
Yentsch, C. S., Menzel, D. W. (1963). A method for the determination of phytoplankton chlorophyll and phaeophytin by fluorescence. Deep-Sea Res. 10: 221–231
Author information
Authors and Affiliations
Additional information
Communicated by R. W. Doyle, Halifax
Rights and permissions
About this article
Cite this article
Demers, S., Therriault, JC., Bourget, E. et al. Small-scale gradients of phytoplankton productivity in the littoral fringe. Mar. Biol. 100, 393–399 (1989). https://doi.org/10.1007/BF00391155
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00391155