The significance of various nitrogen sources for phytoplankton growth in shallow lake and hypertrophie reservoirs

Mátyás Présing, Lajos Vörös, Sándor Herodek, György Abrusán

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2 Citations (Scopus)


The contribution of nitrogen forms to the nitrogen demand of phytoplankton has been estimated in two basins of the oligo-mesotrophic Lake Balaton and its two hypertrophie pollution control reservoirs. The uptake rates were determined using 15N methodology, and by measuring concentration changes with time. N2-fixation were measured by the acetylene-reduction technique. The light dependence of uptake and N2-fixation was described with an exponential saturation equation. The dark uptake velocity of ammonium, nitrate and urea were 60-80%, 4-66% and 16-74% of light-saturated uptake, respectively. Ammonium, urea and nitrate uptakes were 51-85%, 12-42% and 2-8% of the total daily nitrogen uptake. In contrast, N2-fixation was insignificant (0-4%). The interaction of ammonium and nitrate uptake was determined in separate experiments, which demonstrated suppression of nitrate uptake at ammonium addition.

Original languageEnglish
Pages (from-to)361-368
Number of pages8
JournalInternational Review of Hydrobiology
Issue numberSPEC. ISS.
Publication statusPublished - Dec 1 1998



  • Ammonium preference
  • Cyanobacteria
  • Light-dependence
  • Nitrogen uptake

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Aquatic Science

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