Wavelength dependency of the maximum quantum yield of carbon fixation for two red tide dinoflagellates, Heterocapsa pygmaea and Prorocentrum minimum (Pyrrophyta): Implications for measuring photosynthetic rates

Oscar Schofield, Barbara Prézelin, Geir Johnsen

Research output: Contribution to journalArticlepeer-review

35 Scopus citations

Abstract

The influence of photoadaptive state on the spectral dependency of the maximum quantum yield for carbon fixation was determined for two red tide dinoflagellates, Heterocapsa pygmaea Loeblich, Schimdt, et Sherely and Prorocentrum minimum Pavillard. Cultures were acclimated to green, blue, red and white light. The spectral dependency in the light-limited slope of the photosynthesis-irradiance curves (α) was measured with carbon action spectra that, when divided by the spectrally weighted absorption coefficient, provided estimates of the maximum quantum yield (φ(max)) for carbon fixation. Values of (φ(max)) varied with wavelength within each culture conditions as well as between different culture conditions. The degree to which the spectral dependency in (φ(max)) was influenced by the presence of photoprotective carotenoids and/or energy imbalances between photosystems I and II was assessed for both dinoflagellates. The impact of photoprotective pigmentation on the spectral dependency of (φ(max)) was most significant for cells grown under high light conditions reflecting the enrichment of diadinoxanthin. Energy imbalances between the photosystems was assessed by quantifying enhancement effects on spectral (φ(max))in the presence of background illumination. Under our experimental conditions, enhancement effects on carbon action spectra were evident for H. Pygmaea under nearly all growth conditions but were not detectable for P. minimum under any growth condition. We hyphotesize that sensitivity to enhancement effects reflected differences in the structure of the photosynthetic machinery of these two peridinin-containing dinoflagellates. While measurements of (φ(max)) are sensitive to the color of the light within an incubator, the relative impact on the spectral dependency of a was less than the wavelength associated with the cellular absorption properties. Finally we used data to validate an approach proposed by others to aid in the correction of photosynthetic measurements where the in situ spectral light field cannot be easily mimicked. The average error using this approach was 8%, which was significantly error associated with ignoring the spectral dependency in α.

Original languageEnglish (US)
Pages (from-to)574-583
Number of pages10
JournalJournal of Phycology
Volume32
Issue number4
DOIs
StatePublished - Aug 1996

All Science Journal Classification (ASJC) codes

  • Aquatic Science
  • Plant Science

Keywords

  • Heterocapsa pygmaea
  • Prorocentrum minimum
  • Pyrrophyta
  • action spectra
  • chromatic adaptation
  • photosynthesis
  • quantum yield

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