Skip to main content
Log in

The effect of Po river discharge on phytoplankton dynamics in the Northern Adriatic Sea

  • Published:
Marine Biology Aims and scope Submit manuscript

Abstract

An oceanographic transet,, extending from Yugoslavia across the Northern Adriatic Sea to the Po delta in Italy, was occupied during 1972 and 1973 to establish the effect of Po river discharge on the phytoplankton communities of the region. Density distribution showed distinct seasonal features: a winter-spring period of low stability throughout the water column, and a summer period of stratification. The total water-column plant nutrients (nitrate, nitrite, phosphate, silicate) showed a 1.3 to 4.5-fold decrease eastward, with semi-eutrophic conditions restricted to an area off the Po delta. Nannoplankton usually dominated the phytoplankton community, in terms of cell density, surface chlorophyll a concentrations, and surface primary production rates. However, all significant maxima in these characteristics resulted from increases in the microplankton component. Changes in the frequency of major microplankton groups characterized three periods of the annual cycle: September–December, neritic, temperate diatom flora with some littoral elements (e.g. Nitzschia seriata); January–May, neritic, temperate diatom flora of different composition (e.g. Lauderia borealis, Skeletonema costatum); May–August, dinoflagellates (e.g. Prorocentrum micans) at western stations and dinoflagellates plus neritic, warm-water diatoms at eastern stations. The seasonal cycle was characterized by spring and fall maxima tending to coincide with maximum Po river discharge and/or periods of low water-column stability and vertical mixing. The higher nutrient input at western stations was correlated with the co-dominance of only a few species of microplankton during bloom periods, suggesting that these species (S. costatum, N. seriata, and 5 others) can serve as indicators of eutrophic conditions in this region. Assimilation ratios of both the micro- and nannoplankton suggested borderline nutrient conditions. Phosphate was implicated as the limiting nutrient.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Similar content being viewed by others

Literature Cited

  • Anderson, G.C.: The seasonal and geographic distribution of primary productivity off the Washington and Oregon coasts. Limnol. Oceanogr. 9, 282–302 (1964)

    Google Scholar 

  • —: Fractionation of phytoplankton communities off the Washington and Oregon coasts. Limnol. Oceanogr. 10, 477–480 (1965)

    Google Scholar 

  • Beers, J.R. and G.L. Stewart: The vertical distribution of microzooplankton and some ecological observations. J. Cons. int. Explor. Mer 33, 30–44 (1969)

    Google Scholar 

  • Brambati, A., D. Bregant, G. Leonardon and D. Stolfa: Transport and sedimentation in the Adriatic Sea. Pubbl. Inst. sper. talassogr. 489, 1–60 (1973)

    Google Scholar 

  • Buljan, M.: Fluctuations of salinity in the Adriatic Izvj. Inst. Oceanogr. Ribarst. 2, 1–64 (1953)

    Google Scholar 

  • Caperon, J., S.A. Catell and G. Krasnick: Phytoplankton kinetics in a subtropical estuary: eutrophication. Limnol. Oceanogr. 16, 599–607 (1971)

    Google Scholar 

  • Curl, H. and L.F. Small: Variations in photosynthetic assimilation ratios in natural, marine phytoplankton communities. Limnol. Oceanogr. 10 (Suppl.), R67-R73 (1965)

    Google Scholar 

  • Degobbis, D.: On the storage of seawater samples for ammonia determination. Limnol. Oceanogr. 18, 146–150 (1973)

    Google Scholar 

  • Degobbis, D.: The nitrogen cycle and budget in the Northern Adriatic. [In Croatian], 154 pp. M.Sc. thesis, University of Zagreb 1974

  • Doty, M.S. and M. Oguri: Selected features of the isotopic carbon primary production techniques. Rapp. P.-v. Réun. Cons. perm. int. Explor. Mer 144, 47–55 (1958)

    Google Scholar 

  • Eppley, R.W.: Temperature and phytoplankton growth in the sea. Fish. Bull. U.S. 70, 1063–1085 (1972)

    Google Scholar 

  • —, J.N. Rogers and J.J. McCarthy: Half-saturation constants for uptake of nitrate and ammonium by marine phytoplankton. Limnol. Oceanogr. 14, 912–920 (1969)

    Google Scholar 

  • — and J.D.H. Strickland: Kinetics of marine phytoplankton growth. In: Advances in microbiology of the sea, Vol. 1 pp 23–62. Ed. by M.R. Droop and E.J.P. Wood. New York: Academic Press 1968

    Google Scholar 

  • — and W.H. Thomas: Comparison of half-saturation constants for growth and nitrate uptake by marine phytoplankton. J. Phycol. 5, 375–379 (1969)

    Google Scholar 

  • Finenko, Z.Z. and D.K. Krupatkina-Akinina: Effect of inorganic phosphorus on the growth rate of diatoms. Mar. Biol. 26, 193–201 (1974)

    Google Scholar 

  • Fossato, V.U.: Ricerche idrologiche e chimicofisiche sul fiume Po a Polesella. 2. Luglio 1970-Giugno 1972. Archo Oceanogr. Limnol. 18, 59–70 (1973)

    Google Scholar 

  • Franco, P.: Oceanography of Northern Adriatic Sea. 1. Hydrologic features: cruises July–August and October–November 1965. Arch. Oceanogr. Limnol. 16, 1–93 (1970)

    Google Scholar 

  • —: Oceanography of Northern Adriatic Sea. 3. Distribution of the water transparency: cruises July–August and October–November 1965, January–February and April–May 1966. Archo Oceanogr. Limnol. 17, (Suppl.), 99–113 (1972)

    Google Scholar 

  • Gilmartin, M. and N. Revelante: The “island mass” effect on the phytoplankton and primary production of the Hawaiian Islands. J. exp. mar. Biol. Ecol. 16, 181–204 (1974)

    Article  Google Scholar 

  • Gilmartin, M., S. Kveder, D. Degobbis, N. Revelante and N. Smodlake: Hydrographic data collected during cruises in the Northern Adriatic, July–December 1972. Thalassia jugosl. (In press, a)

  • Gilmartin, M. S. Kveder, D. Degobbis, N. Revelante and N. Smodlaka: Hydrographic data collected during cruises in the Northern Adriatic, January–December 1973. Thalassia jugosl. (In press, b)

  • Grese, V.N., E.P. Delalo, E.V. Palvola et A.A. Shmeleva: Sur la compositition et la répartition quantitative du zooplancton dans la Méditerranée orientale. Rapp. P.-v. Réun. Commn int. Explor. Mer Méditerr. 19, p.427 (1968)

    Google Scholar 

  • Hepher, B.: Primary production in fish ponds and its application to fertilization experiments. Limnol. Oceanogr. 7, 131–136 (1962)

    Google Scholar 

  • Holmes, R.W.: Size fractionation of photosynthetic phytoplankton. Spec. scient. Rep. U.S. Fish Wildl. Serv. (Fish.) 279, 69–71 (1958a)

    Google Scholar 

  • —: Surface chlorophyll a, surface primary production, and zooplankton volumes in the Eastern Pacific Ocean. Rapp. P.-v. Réun. Cons. perm. int. Explor. Mer 144, 109–116 (1958b)

    Google Scholar 

  • Ichimura, S.: Environmental gradient and its relation to primary productivity in Tokyo Bay, Rec. oceanogr. Wks Japan 9, 115–128 (1967)

    Google Scholar 

  • Jacques, G.: Aspects quantitatifs du phytoplancton de Banyuls sur Mer (Golfe du Lion), 1965–1968. Vie Milieu 20, 91–126 (1969)

    Google Scholar 

  • —, G. Cahet, M. Fiala et M. Panouse: Enrichissement de communautés phytoplanctoniques néritiques de Méditerranée nord occidentale. J. exp. mar. Biol. Ecol. 11, 287–295 (1973)

    Article  Google Scholar 

  • Jerlov, N.G.: Adriatic Thalassiographic cruise 1955. II. Distribution of suspended material in the Adriatic Sea. Archo Oceanogr. Limnol. 11, 227–250 (1958)

    Google Scholar 

  • Kveder, S., N. Revelante, N. Smodlaka and A. Škrivanić: Some characteristics of phytoplankton and phytoplankton productivity in the Northern Adriatic, Thalassia jugosl. 7, 151–158 (1971)

    Google Scholar 

  • Lund, J.W.G., C. Kipling and E.D. Le Cren: The inverted microscope method of estimating algal numbers and the statistical bases of estimation of counting. Hydrobiologia 11, 143–170 (1958)

    Google Scholar 

  • Malone, T.C.: The relative importance of netplankton and nannoplankton as primary producers in neritic and oceanic tropical waters. Limnol. Oceanogr. 16, 633–639 (1971a)

    Google Scholar 

  • —: The relative importance of nannoplankton and netplankton as primary producers in the California Current System. Fish. Bull. U.S. 69, 799–820 (1971b)

    Google Scholar 

  • Martin, J.H.: Phytoplankton-zooplankton relationships in Narragansett Bay. Limnol. Oceanogr. 10, 185–191 (1965)

    Google Scholar 

  • McAllister, C.D., N. Shah and J.D.H. Strickland: Marine phytoplankton photosynthesis as a function of light intensity: a comparison of methods. J. Fish. Res. Bd Can. 21, 159–181 (1964)

    Google Scholar 

  • McCarthy, J.J., W.R. Taylor and M.E. Loftus: Significance of nanoplankton in the Chesapeake Bay Estuary and problems associated with the measurement of nanoplankton productivity. Mar. Biol., 24, 7–16 (1974)

    Google Scholar 

  • Ministero dei Lavori Pubblici, Servizio Idrografico (Italia): Boll. idrol. mens. June–December, (1972)

  • Ministero dei Lavori Pubblici, Servizio Idrografico (Italia): Boll. idrol. mens. 30 January–December, (1973)

  • Mommaerts, J.: The relative importance of nannoplankton in the North Sea primary production. Br. phycol. J. 8, 13–20 (1973)

    Google Scholar 

  • Mosetti, F.: Alcune ricerche sulle correnti nel golfo di Trieste. Riv. ital. Geofis. 21, 33–38 (1972). (Boll. Ass. Geofis. ital.)

    Google Scholar 

  • — and A. Lavenia: Ricerche oceanografische in Adriatico nel periodo 1966–1968. Boll. geofis teor. appl. 11, 191–218 (1969)

    Google Scholar 

  • Mullin, M.M.: Some factors affecting the feeding of marine copepods of the genus Calanus. Limnol. Oceanogr. 8, 239–250 (1963)

    Google Scholar 

  • Munk, W.H. and G.A. Riley: Absorption of nutrients by aquatic plants. J. mar. Res. 11, 215–240 (1952)

    Google Scholar 

  • Parsons, T.R. and R.J. Le Brasseur: The availability of food to different trophic levels in the marine food chain. In: Marine food chains, pp 325–343. Ed. by J.D. Steele. Berkeley: University of California Press 1970

    Google Scholar 

  • —— and J.D. Fulton: Some observations on the dependence of zooplankton grazing on cell size and concentration of phytoplankton blooms. J. oceanogr. Soc. Japan 23, 10–17 (1967)

    Google Scholar 

  • — and M. Takahashi: Environmental control of phytoplankton cell size. Limnol. Oceanogr. 18, 511–515 (1973)

    Google Scholar 

  • Pigorini, B.: Sources and dispersion of recent sediments of the Adriatic Sea. Mar. Geol. 6, 187–229 (1968)

    Article  Google Scholar 

  • Pojed, I.: Nutrients as limiting factors of primary production in the Northern Adriatic. [In Croatian], 65 pp. M. Sc. thesis, University of Zagreb 1975

  • Pucher-Petković, T.: Recherches préliminaires sur la photosynthèse du nanoplancton et du microplancton dans les eaux de l'Adriatique moyenne. Rapp. P.-v. Réuen. Commn int. Explor. Mer Méditerr. 21, 445–448 (1973)

    Google Scholar 

  • Smayda, T.J.: The suspension and sinking of phytoplankton in the sea. Oceanogr. mar. Biol. A. Rev. 8, 353–414 (1970)

    Google Scholar 

  • Solorzano, L.: Determination of ammonia in natural waters by the phenolhypochlorite method. Limnol. Oceanogr. 14, 799–801 (1969)

    Google Scholar 

  • Sournia, A.: La production primaire planctonique en Méditerranée. Essai de mise à jour. News. co-op. Invest. Mediterr., (spec. Issue) 5, 1–121 (1973). (Bull. Etud. commun Méditerr., Monaco)

    Google Scholar 

  • Steemann-Nielsen, E. and E.A. Jensen: Primary oceanic production. The autotrophic production of organic matter in the ocean. Galathea Rep. 1, 49–136 (1957)

    Google Scholar 

  • Štirn, J.: Pelagial Severnega Jadrana. Raspr. slov. Akad. Znan. Umet. 12, 1–92 (1969)

    Google Scholar 

  • Strickland, J.D.H.: Production of organic matter in the primary stages of the marine food chain. In: Chemical oceanography, Vol 1 pp 477–610. Ed. by J.P. Riley and G. Skirrow. New York: Academic Press 1965

    Google Scholar 

  • — and T.R. Parsons: A practical handbook of seawater analysis. Bull. Fish. Res. Bd Can. 167, 1–311 (1968)

    Google Scholar 

  • Teixeira, C.: Relative rates of photosynthesis and standing stock of net phytoplankton and nanoplankton. Bolm Inst. Oceanogr., S Paulo 13, 53–60 (1963)

    Google Scholar 

  • Thomas, W.H.: On nitrogen deficiency in tropical Pacific Ocean phytoplankton: photosynthetic parameters in poor and rich waters. Limnol. Oceanogr. 15, 380–385 (1970)

    Google Scholar 

  • Van Straaten, L.M.J.V.: Sedimentation in the northwestern part of the Adriatic Sea. Proc. Symp. Colston Res. Soc. 17, 143–162 (1965)

    Google Scholar 

  • Varagnolo, A.M. e G. Monte: Sulla composizione e distribuzione dello zooplancton nell'alto Adriattico nell'inverno e nella primavera 1966. Atti Ist. veneto Sci. 127, 413–441 (1969)

    Google Scholar 

  • ——: Osservazioni sulla composizione e distribuzione dello zooplancton nell'alto Adriatico nell'estate e nell'autunno 1965. Atti Ist. veneto Sci. 129, 229–255 (1971)

    Google Scholar 

  • Voltolina, D.: Phytoplankton in the Gulf of Venice, April 1965–June 1966. Archo Oceanogr. Limnol. 17, 43–70 (1971)

    Google Scholar 

  • Von Brand, T., N.W. Rakestraw and C.E. Renn: The experimental decomposition and regeneration of nitrogenous organic matter in sea water. Biol. Bull. mar. biol. Lab., Woods Hole 72, 165–175 (1937)

    Google Scholar 

  • —— and J.W. Zabor: Decomposition and regeneration of nitrogenous organic matter in sea water. V. Factors influencing the length of the cycle, observations upon the gaseous and dissolved organic nitrogen. Biol. Bull. mar. biol. Lab., Woods Hole 83, 273–282 (1942)

    Google Scholar 

  • Yentsch, C.S. and J.H. Ryther: Relative significance of the net phytoplankton and nannoplankton in the waters of Vineyard Sound. J. Cons. perm. int. Explor. Mer 24, 231–238 (1959)

    Google Scholar 

  • Zore-Armanda, M.: On gradient currents in the Adriatic Sea. Acta adriat. 8, 1–38 (1956)

    Google Scholar 

Download references

Author information

Authors and Affiliations

Authors

Additional information

Communicated by G.F. Humphrey, Sydney

Rights and permissions

Reprints and permissions

About this article

Cite this article

Revelante, N., Gilmartin, M. The effect of Po river discharge on phytoplankton dynamics in the Northern Adriatic Sea. Marine Biology 34, 259–271 (1976). https://doi.org/10.1007/BF00388803

Download citation

  • Accepted:

  • Issue Date:

  • DOI: https://doi.org/10.1007/BF00388803

Keywords

Navigation