Environmental controlling factors of copepod communities in the Gulf of Tunis (south western Mediterranean Sea)
|Author(s)||Ben Lamine Yosra1, Pringault Olivier1, 2, Aissi Mehdi1, Ensibi Cherif1, Mahmoudi Ezzeddine3, Kefi Ons Daly Yahia4, Yahia Mohamed Nejib Daly1|
|Affiliation(s)||1 : Univ Carthage, UR Biol Marine FST Universite El Mannar, Fac Sci Bizerte, Lab Biodivers & Fonctionnement Syst Aquat, Bizerte 7021, Tunisia.
2 : CNRS UM2 IFREMER IRD ECOSYM, Stn Mediterraneenne Environm Littoral, UMR 5119, F-34200 Sete, France.
3 : Univ Carthage, Fac Sci Bizerte, Lab Biosurveillance Environm, Bizerte 7021, Tunisia.
4 : UR Biol Marine FST Universite El Mannar, Inst Natl Agron Tunisie, Grp Rech Ocenog & Ecol Plancton, Tunis 1080, Tunisia.
|Source||Cahiers De Biologie Marine (0007-9723) (Cahiers De Biologie Marine), 2015 , Vol. 56 , N. 3 , P. 213-229|
|WOS© Times Cited||3|
|Keyword(s)||Copepod diversity, Multivariate analysis, Temperature, Salinity, Top-down control, Competition|
The copepod community structure and the distribution of the main groups of zooplankton were studied along an inshore-offshore gradient in the Gulf of Tunis during the rainy and dry seasons of 2007-2008. Hydrological parameters were also measured to assess the potential role of abiotic and biotic factors in the distribution of copepod species. The copepod community in the Gulf of Tunis comprises 86 species dominated by Paracalanus parvus, Clausocalanus lividus, Centropages kroyeri and Acartia clausi. Time had a greater influence than space (horizontal and vertical gradients) in shaping the copepod community structure with a significant influence of the seasons; winter (cold and rainy) resulted in hydrological conditions that were strongly different from those observed in summer (warm and dry). These hydrological differences were concomitant with changes in the community structure, with a high copepod diversity observed in winter while the summer period was characterized by a low specific richness and the dominance of a few species, Centropages kroyeri and Paracalanus parvus along the inshore-offshore gradient and Paracalanus aculeatus along the vertical. Canonical correspondence analysis showed that temperature, salinity and to a lesser extent chlorophyll a were the most important environmental factors structuring the copepod community. Interestingly, temperature and salinity showed a negative significant correlation with copepod specific richness. Competition with grazers (cladoceran) as well as top down control by predators (chaetognaths and siphonophors) were also identified as key factors for the copepod community structure.