Diversity and temporal fluctuations of epiphytes and sessile invertebrates on the rhizomesPosidonia oceanicain a seagrass meadow offTunisia

Abstract

The aim of this work is to study the temporal dynamics of rhizome epiphytes and sessile animals living on the rhizomes of the seagrass Posidonia oceanica in the east of Tunisia. on a fringing reef located in Chebba. Rhizomes were sampled by SCUBA diving at three stations. Samples were examined with a microscope to estimate the cover of macroinvertebrate and macroalgal organisms on the top 10 cm of each rhizome. Results revealed a high diversity of epiphytes on P. oceanica rhizomes with a dominance of red and brown algae, ascidians, and bryozoans. Distinct temporal changes were observed in Oued Lafrann, with a high January cover (winter period) for all groups. These winter increases can be attributed to: (i) the low phenological parameters of P. oceanica in winter that reduce the effects of shading, (ii) life cycles of the epiphytes and invertebrates, (iii) water motion and (iv) grazing.

Variability in patterns of macro-epiphytic leaf community of Posidonia oceanica in the Islands of Kuriate: Western coast of Tunisia

“…Both biomass and percentage cover of macro-epiphytic leaves show a seasonal variability with the high values detected in summer. The variability of assemblages and biomass founded in the present study agrees with those described for P. oceanica meadows in the southern coast of Tunisia by Ben Brahim et al [25,36] and by Mabrouk et al [20] in the region of Mahdia eastern coast of Tunisia, where biomass of macro-epiphytes on leaves of P. oceanica was high in summer and low in winter. Similar results were reported by Zakhama-Sraieb et al [37] in Port El Kantaoui, Tunisia where summer appears a sensitive season marked by the high development and dominance by encrusting Corallinaceae and opportunistic macroalgal species which can reach high cover.…”

“…dredging and filling, propeller scarring) and the release of toxic compounds into coastal waters (e.g. oil spills, industrial discharge) has been discussed by Ben Brahim et al [1,19] and Mabrouk et al [20]. But no studies deal with the effect of natural disturbances such as exposure to wind, wave and tide, on the composition and the abundance of leaf epiphytes in P. oceanica meadows.…”

Epiphyte assemblages of the Mediterranean seagrassPosidonia oceanica: an overview

“…; Mabrouk et al . ). Rhizomes constitute a stabile substrate and can therefore host perennial organisms, with consequent low seasonal variation in assemblage structure.…”

Aggressive Predation Drives Assembly of Adriatic Fish Communities

“…In previous work, C. nodosa beds have been shown in some situations to provide superior foraging returns to fish, which might have been instrumental in this choice. Comparative studies of epifauna on C. nodosa and Posidonia oceanica in the Mediterranean have shown that the epiphyte and epifauna communities associated with C. nodosa can provide equal or even larger quantities of algal and animal food for prey-sized fish [55][56][57][58].…”