Planktonic ciliates in relation to abiotic variables on the north coast of Sfax after environmental restoration: species composition, and abundance-biomass seasonal variation.

Amira REKIK, Michel DENIS, Mathilde DUGENNE, Sami MAALEJ, Habib AYADI

Abstract


The present study is a comprehensive assessment of abundance and composition changes in the ciliate community after an environmental restoration, taking into account seasonal variations. After removal and containment of phosphogypsum on the north coast of Sfax (Tunisia), we investigated the newly restored coastal zone over four successive seasons, autumn 2009 and winter, spring and summer 2010. Results are compared to the pre- restoration situation that we established in July 2007. Overall, ciliate abundance was highly variable and lower than prior restoration. However, ciliate diversity was very high, up to 65 taxa, with a large dominance of tintinnids, up to 85% and a sizable contribution of naked ciliates, up to 15%. Abundance and biomass followed distinct patterns due to large differences in organism biovolumes. Predation on ciliates by copepods is suggested to account for their lower post-restoration abundance which would express a more dynamic copepod activity resulting from the coast restoration as well as a differential impact of pollution on copepods and microorganisms before restoration.

Keywords


Ciliates; Sfax north coast; Gulf of Gabès; TAPARURA restoration project

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