Abstract
The release of dissolved organic carbon (DOC) from phytolankton during photosynthesis, and the utilization of this carbon by planktonic bacteria, was studied using 14CO2 and selective filtration. Natural sea water samples from a coastal area of the Northern Baltic Sea were incubated in the laboratory for detailed studies, and in situ for estimation of annual dynamics. In a laboratory incubation (at +1°C) the concentration of 14C-labelled dissolved organic carbon increased for about 2 h and then reached a steady state, representing about 0. 1% of the total DOC. Labelled organic carbon in the phytoplankton and bacterial fractions continued to increase almost linearly. The continuous increase in the bacterial fraction is thought to represent almost instantaneous utilization of the DOC released from the phytoplankton during photosynthesis. As an annual average, in 4 h in situ incubations, about 65% of the labelled organic carbon was found in the phytoplankton fraction (>3 μm), about 27% in the bacterial fraction (0.2 to 3 μm) and the remaining 8% as DOC (<0.2 μm). Large variations in these percentages were recorded. The measured annual primary production was 93 g C m-2 (March to December), and the estimated bacterial production due to phytoplankton exudates 29 g C m-2. This represents a release of DOC of about 45% of the corrected annual primary production of 110 g C m-2 (assuming a bacterial growth efficiency of 0.6).
Similar content being viewed by others
Literature Cited
Al-Hasan, R.H., S.J. Coughlan, A. Paul and G.E. Fogg: Seasonal variations in phytoplankton and glycolate concentrations in the Menai Straits, Anglesey. J. mar. biol. Ass. U.K. 55, 557–565 (1975)
Allen, H.L.: Dissolved organic carbon: patterns of utilization and turnover in two small lakes. Int. Revue ges. Hydrobiol. 58, 617–624 (1973)
Andrews, P. and P.J. LeB. Williams: Heterotrophic utilization of dissolved organic compounds in the sea. III. J. mar. biol. Ass. U.K. 51, 111–125 (1971)
Bell, W.H., J.M. Lang and R. Mitchell: Selective stimulation of marine bacteria by algal extracellular products. Limnol. Oceanogr. 19, 833–839 (1974)
Choi, C.I.: Primary production and release of dissolved organic carbon from phytolankton in the Western North Atlantic Ocean. Deep-Sea Res. 19, 731–735 (1972)
Crawford, C.C., J.E. Hobbie and K.L. Webb: The utilization of dissolved free amino acids by estuarine microorganisms. Ecology 55, 551–563 (1974)
Derenbach, J.B. and P.J. LeB. Williams: Autotrophic and bacterial production: fractionation of plankton populations by differential filtration of samples from the English Channel. Mar. Biol. 25, 263–269 (1974)
Duursma, E.K.: The production of dissolved organic matter in the sea, as related to the primary gross production of organic matter. Neth. J. Sea. Res. 2, 85–94 (1963)
Fee, E.J.: A numerical model for determining integral primary production and its application to lake Michegan. J. Fish. Res. Bd Can. 30, 1447–1468 (1973)
Fogg, G.E.: Extracellular products of phytoplankton and the estimation of primary productivity. Rapp. P.-v. Réun. Cons. perm. int. Explor. Mer 144, 56–60 (1958)
—: Extracellular products of algae in fresh water. Arch. Hydrobiol. (Beih. Ergebn. Limnol. 5, 1–25 (1971)
Gargas, E. (Ed.): A manual for phytoplankton primary production studies in the Baltic. Publs Baltic mar. Biologists 2, 1–88 (1975). (Copies available from: Water Quality Institute, 11 Agern Allé, DK-2970 Hørsholm, Denmark)
Hamilton, R.D. and K.E. Austin: Assay of relative heterotrophic potential in the sea: the use of specifically labelled glucose. Can. J. Microbiol. 13, 1165–1173 (1967)
Hellebust, J.A.: Extracellular products. In: Algal physiology and biochemistry, pp 838–963. Ed. by W.D. Stewart. Oxford: Blackwell Scientific Publications 1974. (Bot. Monogr. Vol. 10)
Hobbie, J.E. and C.C. Crawford: Respiration corrections for bacterial uptake of dissolved organic compounds in natural waters. Limnol. Oceanogr. 14, 528–532 (1969)
Ignatiades, L.: Studies on the factors affecting the release of organic matter by Skeletonema costatum (Greville) Cleve in field conditions. J. mar. biol. Ass. U.K. 53, 937–956 (1973)
Iturriaga, R. and H.-G. Hoppe: Observations of heterotrophic activity on photoassimilated organic matter. Mar. Biol. 40, 101–108 (1977)
Jolley, E.T. and A.K. Jones: The interaction between Navicula muralis (Grünow) and an associated species of Flavobacterium. Br. phycol. J. 12, 315–328 (1977)
Nalewakjo, C., T.G. Dunstal and H. Shear: Kinetics of extracellular release in axenic algae and in mixed algal-bacterial cultures: significance in estimation of total (gross) phytoplankton excretion rates. J. Physiol. 12, 1–5 (1976)
— and L. Marin: Extracellular production in relation to growth of four planktonic algae and of phytoplankton populations from Lake Ontario. Can. J. Bot. 47, 405–413 (1969)
— and D.W. Schindler: Primary production, extracellular release, and heterotrophy in two lakes in the ELA, Northwestern Ontario. J. Fish. Res. Bd Can. 33, 219–226 (1976)
Ogura, N.: Rate and extent of decomposition of dissolved organic matter in surface seawater. Mar. Biol. 13, 89–93 (1972)
—: Further studies on decomposition of dissolved organic matter in coastal seawater. Mar. Biol. 31, 101–111 (1975)
— and T. Gotoh: Decomposition of dissolved carbohydrates derived from diatoms of Lake Yuno-ko. Int. Revue ges. Hydrobiol. 59, 39–47 (1974)
Payne, W.J.: Energy yields and growth of heterotrophs. A. Rev. Microbiol. 24, 17–25 (1970)
Salonen, K.: Effectiveness of cellulosee and perforated polycarbonate membrane filters in separating bacteria and phytoplankton. Annls bot. fenn. 11, 133–135 (1974)
Shaffer, G.: Baltic coastal dynamics project — the fall downwelling regime of Askö. Contr. Askö Lab., Univ. Stockh. 7, 1–61 (1975)
Sharp, J.H.: Excretion of organic matter by marine phytoplankton: do healthy cells do it? Limnol. Oceanogr. 22, 381–399 (1977)
Stegeman, W.J. and J.K. Hoober: Induction of synthesis of bacterial protein by excretory product of the alga Chlamydonomas reinhardtii y-1. Nature, Lond. 257, 244–246 (1975)
Thomas, J.P.: Release of dissolved organic matter from natural populations of marine phytoplankton. Mar. Biol. 11, 311–323 (1971)
Wiebe, W.J. and D.F. Smith: Direct measurement of dissolved organic carbon release by phytoplankton and incorporation by microheterotrophs. Mar. Biol. 42, 213–223 (1977)
Wright, R.T. and J.E. Hobbie: The uptake of organic solutes in lake water. Limnol. Oceanogr. 10, 22–28 (1965)
Yurkovsky, A.K.: Results of fraction investigation of the organic substance in the Baltic Sea. Proc. Jt oceanogr. Assem. (Tokyo, 1970), 466–467 (1971)
Zimmermann, R.: Estimation of bacterial number and biomass by epifluorescence microscopy and scanning electron microscopy. In: Microbial ecology of a brackish water environment, pp 103–120. Ed. by G. Rheinheimer. Heidelberg: Springer-Verlag 1977
— and L.A. Meyer-Reil: A new control for fluorescence staining of bacterial populations on membrane filters. Kieler Meeresforsch. 30, 24–27 (1974)
Author information
Authors and Affiliations
Additional information
Communicated by T.M. Fenchel, Aarhus
Rights and permissions
About this article
Cite this article
Larsson, U., Hagström, A. Phytoplankton exudate release as an energy source for the growth of pelagic bacteria. Mar. Biol. 52, 199–206 (1979). https://doi.org/10.1007/BF00398133
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00398133