The effect of coastal engineering works in the Oosterschelde (SW Netherlands) on zooplankton abundance and species composition
Seyuom, S.T. (1993). The effect of coastal engineering works in the Oosterschelde (SW Netherlands) on zooplankton abundance and species composition. MSc Thesis. VUB: Brussel. 46 pp.
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Document type: Dissertation
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| Abstract |
Zooplankton samples and environmental variables were collected and analyzed to get an insight in the effect of large-scale coastal engineering works in the Oosterschelde on the zooplankton species composition and abundance. The zooplankton abundance and species composition in after barrier years 1988, 1989, 1992 and 1993 were compared statistically with that of before barrier construction year 1983 and during barrier construction years 1984-1987. The relationship between the zooplankton and the environmental variables were analyzed. The result showed that the abundance of Temora longicornis significantly, increased from before and during barrier construction years to after barrier construction years 1988 and 1989 and again decreased in the years 1992 and 1993. The abundance of the genus Acartia did not change significantly but a change in species succession was observed. Acartia tonsa dominated in prebarrier and till 1986 during barrier construction period. Acartia clausi became more important from 1987 onwards. In 1992, A. tonsa was again found to be dominant in summer. Polychaete larvae did not show a significant change in abundance between the various periods. The abundance of Balanus spp. nauplii decreased in the after barrier years 1989, 1992 and 1993. Statistical analysis indicated that among the environmental variables, temperature and nutrient (nitrate + silicate) concentration had a significant effect on zooplankton abundance. The effect of temperature can be considered as purely seasonal. It is hypothesized that the effect of nutrients on suspension feeding zooplankton would be indirect through their effects on phytoplankton size distribution and species composition. Further study is required to analyze the important link between the zooplankton and nutrients in the Oosterschelde, and to verify continuity of trends in zooplankton in recent years. |
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