Zooplankton distribution in four ponds of different salinity: a seasonal study in the solar salterns of Sfax (Tunisia)

Abstract

The seasonal distribution of metazooplankton and large-sized ciliates was studied in four ponds of different salinity in the solar salterns of Sfax (Tunisia). Total zooplankton abundance varied from 1 · 10 3 to 4.7 · 10 6 ind m )3 . Salinity had a negative effect on the abundance of copepods and rotifers which were absent in the pond with the highest salt concentration (180&) in which the number of taxa was low and Artemia or the ciliate Fabrea largely dominated the zooplankton community. Temperature and the presence of Dunaliella salina as prey appeared as key factors in controlling the abundance of Artemia, while organic detritus appeared as important in the diet of Fabrea. Change in zooplankton species composition along the hypersaline gradient (40-90&) was primarily related to salinity. However, our data suggest the importance of both the abundance and composition of food in the spatial and temporal variations of some zooplankton species.

Salinity and freshwater discharge determine rotifer distribution at the Mossoró River Estuary (Semiarid Region of Brazil)

“…Due to the well-known negative influence of salinity on many zooplankton species (e.g. Hammer, 1993;Lansac-Tôha and Lima, 1993;Keller and Conlin, 1994;Williams, 1998;Epifanio and Garvine, 2001;Herbst, 2001;Ara, 2002;Derry et al, 2003;Toumi et al, 2005), one would expect to find lower rotifer richness and abundance at zones with higher salinity, but the opposite pattern was observed for the present study, salinity, richness and abundance showing higher values in the UZ. However, seasonally, salinity and rotifer numbers showed major contrasting patterns which were the most critical structuring forces on rotifer distribution in the present study.…”

“…Miracle and Serra, 1989;Hammer, 1993;Lansac-Tôha and Lima, 1993;Keller and Conlin, 1994;Onwudinjo and Egborge, 1994;Williams, 1998;Epifanio and Garvine, 2001;Herbst, 2001;Ara, 2002;Derry et al, 2003;Toumi et al, 2005;Fontaneto et al, 2006;Zakaria et al, 2007). However, despite these previously accomplished studies, new questions frequently arise and contrasting results suggest that the influence of environmental factors on species composition is site-dependent.…”

Impacts of restoration of an uncontrolled phosphogypsum dumpsite on the seasonal distribution of abiotic variables, phytoplankton, copepods, and ciliates in a man-made solar saltern

“…The copepod composition in the Sfax saltern is comparable to other Mediterranean coastal environments, with, however, an evident prevalence of halophylic species in adaptation to the rising salt concentration (Abdennadher et al 2012;Badosaetal.2006;Hannachi et al 2011). During this study, we found ten species in pond A1 cited for the first time in the Sfax solar saltern, compared with the findings of Toumi et al (2005) in their previous study period of 1999-2000. Among them were large species such as Centropages kroyeri and Clytemnestra scutellata, known to indicate a good ecosystem status (Kambursha and Fonda-Umani 2006) and/or a modification in the prey spectrum ( C a l b e te ta l .2001).…”

Temperature and salinity as interacting drivers of species richness of planktonic rotifers in Turkish continental waters

“…A positive correlation between temperature and species richness in freshwater has been described for aquatic invertebrates in general (Friberg et al 2001), and for zooplankton in particular (Hessen et al 2007;Kaya & Altındağ 2007). Salinity is another important factor affecting species richness in continental water bodies (Lancaster & Scudder 1987;Williams et al 1990;Derry et al 2003), with inland saline systems hosting less species than freshwater bodies (Hart et al 1998;Schallenberg et al 2003;Toumi et al 2005;Shiel et al 2006). Salinity of inland waters may increase due to evaporation; thus, a positive correlation between salinity and temperature should be expected.…”