EFFECT OF NITROGEN AND PHOSPHORUS SUPPLY ON GROWTH AND TISSUE COMPOSITION OF ULVA FENESTRATA AND ENTEROMORPHA INTESTINALIS (ULVALES, CHLOROPHYTA)1

Authors

  • Bo R. Björnsäter,

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    1. College of Oceanography, Oregon State University, Corvallis, Oregon 97331
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  • Patricia A. Wheeler

    1. College of Oceanography, Oregon State University, Corvallis, Oregon 97331
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    • 3

      Department of Plant Physiology, University of Göteborg Carl Skottsbergs Gata 22, S-413 19 Göteborg, Sweden.


  • 1

    Received 27 December 1989. Accepted 16 August 1990.

  • This work was supported by a grant from the Swedish-American Foundation to B. R. Björnsäter and in part by NSF grant OCE-8501369 to P. A. Wheeler and R. M. Fujita. Jane Lubchenco and S. V. Smith provided valuable comments on an earlier draft of the manuscript.

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Abstract

The chlorophyte macroalgae Ulva fenestrata (Postels and Ruprecht) and Enteromorpha intestinalis (Linnaeus) Link. were grown under various nutrient regimes in indoor semi-continuous and batch cultures. Tissue nitrogen contents ranged from 1.3–5.4% N (dry wt), whereas tissue P ranged from 0.21–0.56% P (dry wt). Growth in low nitrogen medium resulted in N:P ratios of 5–8, whereas growth in high nitrogen medium resulted in N:P ratios of 21–44. For U. fenestrata, tissue N:P < 16 was indicative of N-limitation. Tissue N:P 16–24 was optimal for growth and tissue N:P > 24 was indicative of P-limitation. Growth of U. fenestrata was hyperbolically related to tissue N but linearly related to tissue P. Phosphorus-limited U. fenestrata maintained high levels of tissue N, but N-limited algae became depleted of P. For E. intestinalis, tissue N remained at maximum levels during P-limitation whereas tissue P decreased to about 85% of maximal levels during N-limitation. Growth rates for U. fenestrata decreased faster during P-limitation than during N-limitation. Simultaneously, tissue P was depleted faster than tissue N. Our results suggest that comparing tissue N and P of macroalage grown in batch cultures is useful for monitoring the nutritional status of macroalgae.

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