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Spatial scale variability in shoot density and epiphytic leaves of Posidonia oceanica on Kerkennah Island (Tunisia) in relation to current tide effects
Author(s) -
Ben Brahim Mounir,
Mabrouk Lotfi,
Hamza Asma,
Mahfoudhi Mabrouka,
Bouain Abderahmen,
Aleya Lotfi
Publication year - 2015
Publication title -
marine ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.668
H-Index - 58
eISSN - 1439-0485
pISSN - 0173-9565
DOI - 10.1111/maec.12231
Subject(s) - epiphyte , posidonia oceanica , oceanography , benthic zone , biomass (ecology) , current (fluid) , potamogetonaceae , ecology , algae , hydrozoa , spatial distribution , scuba diving , biology , seagrass , environmental science , cnidaria , geology , habitat , coral , remote sensing
Abstract A study was undertaken of the patterns of spatial variability, epiphytic biomass and distribution of epiphytic fauna and flora of P osidonia oceanica . Samples were taken at four stations located approximately 4 km apart, exposed to different current conditions. Stations A and B, situated near the Oued Mimoun tidal channel with its relatively strong bi‐directional flows, were affected by high current tide. The other two stations, North Oued Mimoun (L1) and South Oued Mimoun (L2), were located further from the channel, in low current tide conditions. Sampling was conducted in the Attaya area of Kerkennah Island (Tunisia) in August 2009 at depths between 2 and 3 m, with the results indicating differences among the stations. Shoot density decreased when exposed to high levels of hydrodynamic activity generated by current tides whereas the epiphytic biomass of P. oceanica leaves decreased at sheltered stations located far from the channel. Epiphytic algae such as Heterokontophyta, Rhodophyta and Chlorophyta, and epiphytic fauna represented by Bryozoa, Hydrozoa, Annelida, Porifera and Tunicata, dominated the epiphytic assemblages and were abundant at the station most exposed to high current tide hydrodynamics. Cyanobacteria, however, were dominant in stations exposed to low current tide.