Phosphorus-limited photosynthesis and growth of Sargassum natans and Sargassum fluitans (Phaeophyceae) in the western North Atlantic

https://doi.org/10.1016/0198-0149(86)90099-3Get rights and content

Abstract

Growth enrichment studies utilizing in vitu cage cultures and a shipboard flowing seawater culture system were conducted with whole-plant populations of pelagic Sargassum-S. natans and S. fluitans (Phaeophyceaa)-in the western Sargasso Sea and at Looe Key Marine Sanctuary adjacent to the Straits of Florida. Growth rates of both species ranged from 0.03 to 0.04 doublings d−1 in control cultures receiving no enrichment and in cultures receiving either NO3 or NH4+ enrichment; in contrast, growth rates ranged from 0.05 to 0.08 doublings d−1 in cultures receiving PO43− enrichment. Midday photosynthetic rates of S. natans and S. fluitans were also two-fold higher with PO43− enrichment, ca. 2.3 mgC g dryw−1 h−1 compared to 1.0 to 1.5 mgC g dry wt−1 h−1 in the NH4+, NO3, and control treatments. These data suggest the pelagic Sargassum may grow faster than previously thought and that phosphorus, rather than nitroge, may be the primary nutrient limiting growth and productivity of these plants.

References (34)

  • E.J. Carpenter et al.

    Production of pelagic Sargassum and a blue green epiphyte in the Western Sargasso Sea

    Limnology and Oceanography

    (1974)
  • J.L. Culliney

    Measurement of reactive phosphorus associated with pelagic Sargassum in the northwestern Sargasso Sea

    Limnology and Oceanography

    (1970)
  • J.K. Dooley

    Fishes associated with the pelagic Sargassum complex, with a discussion of the Sargassum community

    Contributions in Marine Science, University of Texas

    (1972)
  • C. Doremus

    Geochemical control of dinitrogen fixation in the open ocean

    Biol. Oceanography

    (1982)
  • J.C. Goldman et al.

    Growth rate influence on the chemical composition of phytoplankton in oceanic waters

    Nature, London

    (1979)
  • G.P. Harris

    Photosynthesis, productivity and growth: the physiological ecology of phytoplankton

    Ergebnisse der Limnologie

    (1978)
  • K.L. Howard et al.

    Distribution and production of Sargassum in the waters off the Carolina coast

    Botanica Marina

    (1969)
  • Cited by (0)

    View full text