The dynamics of zooxanthellae populations: A long-term study in the field

Science

Volumn 283, Issue 5403, 1999, Pages 843-845

  Fagoonee, I ^a   Wilson, H B ^b   Hassell, M P ^b   Turner, J R ^c  

^a UNIVERSITY OF MAURITIUS   (Mauritius)

^b IMPERIAL COLLEGE LONDON   (United Kingdom)

^c BANGOR UNIVERSITY   (United Kingdom)

Author keywords

[No Author keywords available]

Indexed keywords

ALGA; ARTICLE; BLEACHING; ECOSYSTEM; ENVIRONMENTAL MONITORING; GREENHOUSE EFFECT; NONHUMAN; PRIORITY JOURNAL;

ALGAE; ANTHOZOA;

EID: 0033524844     PISSN: 00368075     EISSN: None     Source Type: Journal    
DOI: 10.1126/science.283.5403.843     Document Type: Article

References (31)

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6. C. B. Cook, A. Logan, J. Ward, B. Luckhurst, C. J. Berg Jr., Coral Reefs 9, 45 (1990); R. D. Gates, ibid. 8, 193 (1990); T. J. Goreau and R. L. Hayes, Ambio 23, 176 (1994); B. E. Brown, M. D. A. Le Tissier, R. P. Dunne, Mar. Ecol. Prog. Ser. 105, 209 (1994); W. K. Fitt and M. E. Warner, Biol. Bull. 189, 298 (1995).
7. C. B. Cook, A. Logan, J. Ward, B. Luckhurst, C. J. Berg Jr., Coral Reefs 9, 45 (1990); R. D. Gates, ibid. 8, 193 (1990); T. J. Goreau and R. L. Hayes, Ambio 23, 176 (1994); B. E. Brown, M. D. A. Le Tissier, R. P. Dunne, Mar. Ecol. Prog. Ser. 105, 209 (1994); W. K. Fitt and M. E. Warner, Biol. Bull. 189, 298 (1995).
8. C. B. Cook, A. Logan, J. Ward, B. Luckhurst, C. J. Berg Jr., Coral Reefs 9, 45 (1990); R. D. Gates, ibid. 8, 193 (1990); T. J. Goreau and R. L. Hayes, Ambio 23, 176 (1994); B. E. Brown, M. D. A. Le Tissier, R. P. Dunne, Mar. Ecol. Prog. Ser. 105, 209 (1994); W. K. Fitt and M. E. Warner, Biol. Bull. 189, 298 (1995).
9. M. P. Lesser, W. R. Stochaj, D. W. Tapley, J. M. Shick, Coral Reefs 8, 225 (1990); D. F. Gleason and G. M. Wellington, Nature 365, 836 (1993).
10. M. P. Lesser, W. R. Stochaj, D. W. Tapley, J. M. Shick, Coral Reefs 8, 225 (1990); D. F. Gleason and G. M. Wellington, Nature 365, 836 (1993).
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13. 2 with an average depth of 2.5 m. There is a high degree of eutrophication in the lagoon with only 20% live coral cover (80 to 90% Acropora, and a few occurrences of Pocillopora and Porites), algal proliferation (50% Padina, 10% Sargassum, 5% Turbinaria, 5% Valonia, 5% Galaxaura, and 25% other), and a considerable degree of anthropogenic activity (swimming, boating, fishing, snorkeling, water-skiing). A colony was selected that lay in about 2 m of water, depending on the state of the tide. Coral samples were collected by breaking off one live coral tip (2 to 3 cm) from a randomly selected part of the same colony each week.
14. Dissolved oxygen and surface water temperature (at depths of 0.5 to 1.0 m) were taken in situ, and nitrate and phosphate concentrations were determined from water samples in the laboratory. Zooxanthellae were extracted from live coral tips according to Drew's technique (13) after decalcifying in 5% HCl. Aliquots of homogeneous extracts were placed on a hemocytometer (improved Neubauer counting chamber, depth 0.1 mm), and zooxanthellae cells were counted under an inverted microscope at ×400. The aluminum foil method of Marsh [J. A. Marsh, Ecology 55, 255 (1970)] was used to calculate the surface area of the coral tip from which the zooxanthellae were extracted. Data on amounts of solar radiation and rainfall in the area were obtained from the Mauritius meteorological office.
15. L. Muscatine, P. G. Falkowski, Z. Dubinsky, P. A. Cook, L. R. McCloskey, Proc. R. Soc. London Ser. B 236, 311 (1989).
16. P. G. Falkowski, Z. Dubinsky, L. Muscatine, L. R. McCloskey, Bioscience 43, 606 (1993).
17. 2 = 0.84; the probability of the null model being rejected is P = 0.016 (as calculated by parametric bootstrapping).
18. E. A. Drew, J. Exp. Mar. Biol. Ecol. 9, 71 (1972).
19. J. Stimson, ibid. 214, 35 (1997).
20. L. R. McCloskey, D. S. Wethey, J. W. Porter, Monogr. Oceanogr. Methodol. 55, 379 (1978).
21. -1) all fluctuated greatly over the study period (n = 147).
22. A. M. Szmant, L. M. Ferrer, L. M. Fitzgerald, Mar. Biol. 104, 119 (1990); F. Marubini and P. S. Davies, ibid. 127, 319 (1996).
23. A. M. Szmant, L. M. Ferrer, L. M. Fitzgerald, Mar. Biol. 104, 119 (1990); F. Marubini and P. S. Davies, ibid. 127, 319 (1996).
24. Because dissolved oxygen in the water column is continuous with water in the coelenteron, it may lead to increased oxygen concentration within the coral. High concentrations of oxygen within the coral can precipitate bleaching [M. P. Lesser, Coral Reefs 16, 187 (1997)].
25. Because the data collected were from the tip of the coral and because growth is expected to be greatest at this point [E. H. Gladfelter, Biol. Bull. (Woods Hole) 165, 811 (1983); F. P. Wilkerson, D. Kobayashi, L. Muscatine, Coral Reefs 7, 29 (1988)], the observed variability may be attributable in part to a combination of coral growth and zooxanthellae division to exploit the newly available space [R. J. Jones and D. Yellowlees, Philos. Trans. R. Soc. London Ser. B 352, 457 (1997)].
26. Because the data collected were from the tip of the coral and because growth is expected to be greatest at this point [E. H. Gladfelter, Biol. Bull. (Woods Hole) 165, 811 (1983); F. P. Wilkerson, D. Kobayashi, L. Muscatine, Coral Reefs 7, 29 (1988)], the observed variability may be attributable in part to a combination of coral growth and zooxanthellae division to exploit the newly available space [R. J. Jones and D. Yellowlees, Philos. Trans. R. Soc. London Ser. B 352, 457 (1997)].
27. Because the data collected were from the tip of the coral and because growth is expected to be greatest at this point [E. H. Gladfelter, Biol. Bull. (Woods Hole) 165, 811 (1983); F. P. Wilkerson, D. Kobayashi, L. Muscatine, Coral Reefs 7, 29 (1988)], the observed variability may be attributable in part to a combination of coral growth and zooxanthellae division to exploit the newly available space [R. J. Jones and D. Yellowlees, Philos. Trans. R. Soc. London Ser. B 352, 457 (1997)].
28. Some of this variability is undoubtedly because different parts of the same colony were sampled and the orientation of the coral branch to incident light is known to affect zooxanthellae density [L. R. McCloskey and L. Muscatine, Proc. R. Soc. London Ser. B 222, 215 (1984); Z. Dubinsky, P. G. Falkowski, J. W. Porter, L. Muscatine, ibid., p. 203]. In addition, it is possible that different strains of zooxanthellae exist in different parts of the colony [ R. Rowan, N. Knowlton, A. Baker, J. Jara, Nature 388, 265 (1997)]. Thus, the data collected reflect the normal degree of zooxanthellae variability expected over an entire colony. However, this cannot be the only cause of variation, as the test for density dependence specifically examined and rejected the hypothesis that the sole cause of the variability through time is just random sampling from some distribution of zooxanthellae abundance.
29. Some of this variability is undoubtedly because different parts of the same colony were sampled and the orientation of the coral branch to incident light is known to affect zooxanthellae density [L. R. McCloskey and L. Muscatine, Proc. R. Soc. London Ser. B 222, 215 (1984); Z. Dubinsky, P. G. Falkowski, J. W. Porter, L. Muscatine, ibid., p. 203]. In addition, it is possible that different strains of zooxanthellae exist in different parts of the colony [ R. Rowan, N. Knowlton, A. Baker, J. Jara, Nature 388, 265 (1997)]. Thus, the data collected reflect the normal degree of zooxanthellae variability expected over an entire colony. However, this cannot be the only cause of variation, as the test for density dependence specifically examined and rejected the hypothesis that the sole cause of the variability through time is just random sampling from some distribution of zooxanthellae abundance.
30. Some of this variability is undoubtedly because different parts of the same colony were sampled and the orientation of the coral branch to incident light is known to affect zooxanthellae density [L. R. McCloskey and L. Muscatine, Proc. R. Soc. London Ser. B 222, 215 (1984); Z. Dubinsky, P. G. Falkowski, J. W. Porter, L. Muscatine, ibid., p. 203]. In addition, it is possible that different strains of zooxanthellae exist in different parts of the colony [ R. Rowan, N. Knowlton, A. Baker, J. Jara, Nature 388, 265 (1997)]. Thus, the data collected reflect the normal degree of zooxanthellae variability expected over an entire colony. However, this cannot be the only cause of variation, as the test for density dependence specifically examined and rejected the hypothesis that the sole cause of the variability through time is just random sampling from some distribution of zooxanthellae abundance.
31. We thank S. Davy for reviewing the manuscript and the British Council for sponsoring the link between the University of Mauritius and Imperial College, London and the Link in Marine Environmental Science between the University of Mauritius and the University of Wales, Bangor. The work was also supported by a Natural Environment Research Council (NERC) Advanced Fellowship (H.B.W.) and by a grant from NERC (M.P.H.).