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Periphyton density and shading in relation to tidal depth and fiddler crab activity in intertidal seagrass beds of the Banc d’Arguin (Mauritania)

  • M. J. M. Hootsmans
  • J. E. Vermaat
  • J. A. J. Beijer
Conference paper
  • 52 Downloads
Part of the Developments in Hydrobiology 86 book series (DIHY, volume 86)

Abstract

Periphyton development was studied on microscopic glass slides and leaves of Zostera noltii Hornern, in an intertidal area in the Banc d’Arguin (Mauritania). The effects of shading, tidal depth and grazing activities by the fiddler crab Uca tangeri Eydoux were evaluated. For all experiments, periphyton ash content was high (52–93%) and ash-free dry weight ranged between 0.10-0.63 mg cm-2. Slides accumulated more periphyton than leaves.

Artificial shading (62–99%) for 13 days had no effect on periphyton densities on leaves. Increased tidal depth resulted in higher ash-free dry weight on slides, but in lower ash-free dry weight on leaves. Significant variation along the coastline also existed. The effect of fiddler crabs was studied using exclosures. Presence of fiddler crabs reduced periphyton density on slides, whereas light transmittance was increased. On leaves, no significant fiddler crab effect was found. This difference between leaves and slides was probably caused by a storm at the day before the end of the experiment, and by the higher periphyton density on slides as compared with leaves. As visual inspection during the experiment showed clear differences in appearance of leaves inside and outside the exclosures, the storm probably sloughed off mainly the older leaves, i.e. those on which the differences in periphyton cover were the highest.

It is hypothesized that periphyton accumulation is higher with increased tidal depth, whereas fiddler crab grazing pressure also increases in this direction. The result is a decreased periphyton density with increased tidal depth.

The presently found light extinction coefficients (mean 0.8 m-1) and periphyton light attenuance (up to 25%) in Banc d’Arguin are not likely to affect seagrass leaf growth.

Key words

extinction coefficient grazing periphyton seagrasses Uca tangeri Zostera noltii 

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References

  1. Borum, J. & S. Wium-Andersen, 1980. Biomas s and production of epiphytes on eelgrass (Zostera marina L.) in the 0resund, Denmark. Ophelia, Suppl. 1: 57–64.Google Scholar
  2. Brönmark, C, 1985. Interactions between macrophytes, epiphytesnd herbivores: an experimental approach. Oikos 45: 26–30.CrossRefGoogle Scholar
  3. Brönmark, C, 1989. Interactions between epiphytes, macrophytes and freshwater snails: a review. J. Moll. Stud. 55: 299–311.CrossRefGoogle Scholar
  4. Bulthuis, D. A. & W. J. Woelkerling, 1983. Biomass accumulation and shading effects of epiphytes on the leaves of Heterozostera tasmanica, in Victoria, Australia. Aquat. Bot. 16: 137–148.CrossRefGoogle Scholar
  5. Cambridge, M. L., A. W. Chiffings, C. Brittan, L. Moore & A. J. McComb, 1986. The loss of seagrass in Cockburn Sound, Western Australia. II. Possible causes of seagrass decline. Aquat. Bot. 24: 269–285.CrossRefGoogle Scholar
  6. Dennison, W. C, 1987. Effects of light on seagrass photosynthesis, growth and depth distribution. Aquat. Bot. 27: 15–26.CrossRefGoogle Scholar
  7. Eminson, D. & B. Moss, 1980. The composition and ecology of periphyton communities in freshwaters 1. The influence of host type and external environment on community composition. Br. Phycol. J. 15: 429–446.CrossRefGoogle Scholar
  8. Giesen, W. B. J. T., M. M. van Katwijk & C. den Hartog, 1990. Eelgrass condition and turbidity in the Dutch Wadden Sea. Aquat. Bot. 37: 71–85.CrossRefGoogle Scholar
  9. Hootsmans, M. J. M. & J. E. Vermaat, 1985. The effect of periphyton-grazing by three epifaunal species on the growth of Zostera marina L. under experimental conditions. Aquat. Bot. 22: 83–88.CrossRefGoogle Scholar
  10. Jiménez, C., F. X. Niell & P. Algarra, 1987. Photo synthetic adaptation of Zostera noltii Hörnern. Aquat. Bot. 29: 217–226.CrossRefGoogle Scholar
  11. Phillips, G. L., D. Eminson & B. Moss, 1978. A mechanism to account for macrophyte decline in progressively eutrophicated waters. Aquat. Bot. 4: 103–126.CrossRefGoogle Scholar
  12. Sand-Jensen, K., 1977. Effect of epiphytes on eelgrass photosynthesis. Aquat. Bot. 3: 55–63.CrossRefGoogle Scholar
  13. Sand-Jensen, K. & J. Borum, 1984. Epiphyte shading and its effect on photosynthesis and diel metabolism of Lobelia dortmanna L. during the spring bloom in a Danish lake. Aquat. Bot. 20: 109–119.CrossRefGoogle Scholar
  14. Sand-Jensen, K. & M. Søndergaard, 1981. Phytoplankton and epiphytic development and their shading effect on submerged macrophytes in lakes of different nutrient status. Int. Revue ges. Hydrobiol. 66: 529–552.CrossRefGoogle Scholar
  15. SAS Institute Inc., 1985. SAS/STAT Guide for personal computers, version 6 edition. Cary, N.C., pp. 378.Google Scholar
  16. Silberstein, K., A. W. Chiffings & A. McComb, 1986. The loss of seagrass in Cockburn Sound, Western Australia. III. The effect of epiphytes on productivity of Posidonia australis Hook. f. Aquat. Bot. 24: 355–371.CrossRefGoogle Scholar
  17. Vermaat, J. E. & M. J. M. Hootsmans, 1991. Periphyton dynamics in a temperature-light gradient. In M. J. M. Hootsmans & J. E. Vermaat, Macrophytes, a key to understanding changes caused by eutrophication in shallow freshwater ecosystems. IHE, Delft, The Netherlands, IHE Report Series 21: 157–187.Google Scholar
  18. Vermaat, J. E., J. A. J. Beijer, R. Gijlstra, M. J. M. Hootsmans, C. J. M. Philippart, N. W. Van den Brink & W. Van Vierssen, 1993. Leaf dynamics and standing stocks of intertidal Zostera noltii Hornern, and Cymodocea nodosa (Ucria) Ascherson in the Banc d’Arguin (Mauritania). Hydrobiologia 258: 59–72.CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media Dordrecht 1993

Authors and Affiliations

  • M. J. M. Hootsmans
    • 1
  • J. E. Vermaat
    • 1
  • J. A. J. Beijer
    • 1
  1. 1.Dept. of Nature ConservationWageningen Agricultural UniversityWageningenThe Netherlands

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