A long-term study on Coolia monotis distribution from the south-east Mediterranean Sea. (30th December 2020)

• Record Type: Journal Article
• Authors: Abdennadher, Moufida; Zouari, Amel Bellaaj; Sahnoun, Wafa Feki; Walha, Lamia Dammak; Mahfoudi, Mabrouka; Hamza, Asma
• Is Part Of: Continental shelf research. Volume 211(2020)
• Publication Date: 2020-12-30
• Subjects: Coolia monotis -- South-east mediterranean sea -- Gulf of gabès -- Distribution -- Growth rate -- Salinity; Continental shelf -- Periodicals; Submarine geology -- Periodicals; 551.41
• DOI: 10.1016/j.csr.2020.104267
• Languages: English
• ISSNs: 0278-4343

Abstract

Abstract: The potentially toxic species Coolia monotis is widespread along the Mediterranean coasts. The Gulf of Gabès is one of the affected areas in the south-eastern part of the Mediterranean Sea. Distribution patterns of C. monotis in relation to temperature and salinity were investigated at 24 monitoring sites along the Gulf of Gabès coasts during 22 years (1997–2018). The analysis of C. monotis occurrence in the water column revealed a seasonal trend with high abundances (≥10 5 cells l −1 ) recorded during winter. C. monotis was widely distributed in Gabès Gulf, it was most abundant in the southern part, particularly at the Cotusal Channel site, which is surrounded by marine solar salterns, where the highest concentration (2.54 × 10 6 cells l −1 ), the maximum mean abundance (3.74 ± 51.87 × 10 4 cells l −1 ) and the highest number of observations (75) were recorded over the study period. C. monotis was observed within a wide range of temperature (9–31.6 °C) and salinity (31–59) with high abundances (>10 5 cells l −1 ) occurring at water salinity and temperature of 41.9–45 and 15–17.3 °C, respectively. A positive correlation was found between the abundance of C. monotis and salinity ( p < 0.05), whereas no correlation was found as regards temperature. Culture experiments were conducted under varying salinity regimes (10–50) with C. monotis strain (Com.10) isolated from the Cotusal Channel. Growth occurred at salinities between 20 and 50 and the maximum growth rate of 0.23 day −1 was recorded at a salinity of 40. Results suggest that seawater salinity plays a central role in the C. monotis blooms development. Highlights: Long-term dynamic of C. monotis in relation to temperature and salinity along the Gulf of Gabès. Analysis of a 22-year phytoplankton monitoring data set for 24 sites. A positive correlation between C. monotis abundance and salinity. Growth at salinity between 20 and 50, peaking at 40.