Spatial variations of planktonic ciliates, predator-prey interactions and their environmental drivers in the Gulf of Gabes-Boughrara lagoon system. (5th June 2021)

• Record Type: Journal Article
• Authors: Rekik, Amira; Kmiha-Megdiche, Salma; Drira, Zaher; Pagano, Marc; Ayadi, Habib; Bellaaj Zouari, Amel; Elloumi, Jannet
• Is Part Of: Estuarine, coastal and shelf science. Volume 254(2021)
• Publication Date: 2021-06-05
• Subjects: Gulf of gabes- boughrara lagoon system -- Planktonic ciliates -- Predator-prey interactions -- Environmental parameters; Estuarine oceanography -- Periodicals; Coasts -- Periodicals; Estuarine biology -- Periodicals; Seashore biology -- Periodicals; Coasts; Estuarine biology; Estuarine oceanography; Seashore biology; Periodicals; 551.461805
• DOI: 10.1016/j.ecss.2021.107315
• Languages: English
• ISSNs: 0272-7714

Abstract

Abstract: Spatial variability of ciliates in relation to environmental variables and abundance of heterotrophic prokaryotes, picoeukaryotes, nanoeukaryotes, microphytoplankton and mesozooplankton were studied in the Gulf of Gabes- Boughrara lagoon system in the surface layer and at the water-sediment interface between 9 and April 15, 2017. Results revealed a striking difference between the two ecosystems, with higher temperature and salinity and high availability of nitrite and total nitrogen concentrations in the Boughrara lagoon, probably generated by limited exchanges of water with the Gulf of Gabes associated with disturbed areas in the lagoon. Ciliates abundance was slightly higher in the Gulf of Gabes (16–19 × 10 2 cells l −1 ) than in the Boughrara lagoon (13–16 × 10 2 cells l −1 ), but the species richness was significantly higher in the Boughrara lagoon (40 taxa in the surface layer and 35 taxa at the water-sediment interface) than in the Gulf of Gabes (35 taxa in the surface layer and 33 taxa at the water-sediment interface). The ciliate community was characterized by the predominance of Spirotrichea. Tintinnids were more abundant than naked ciliates in both sampled ecosystems, except in a few stations. Some tintinnid species, such as Tintinnopsis radix, T. nana and T. parvula, showed high abundance, indicating their tolerance to environmental pollution. The dominant species T. beroidea, T. nana and Strombidium compressum showed significant relationships with nutrient concentrations, illustrating their affinity for highly eutrophic sites. Regression and correlation analyses suggest food dependence of Spirotrichea and tintinnids up on picoeukaryotes, whereas naked ciliates appeared more controlled by the availability of nanoeukaryotes and microphytoplankton. Metazooplankton abundance showed no significant relationships with ciliate abundance. Highlights: Ciliate community composition was dominated by tintinnids. Naked ciliates were dominated by Spirotrichs. Temperature showed negative effect on the structure of total ciliates and Spirotrichea. Ciliate diversity, in the Boughrara lagoon, was more important than in the Gulf of Gabes.