Résumé

The spatial and temporal variation of phytoplankton
communities including HAB species in relation
to the environmental characteristics was investigated
in the protected meso-oligotrophic Mellah lagoon
located in the South Western Mediterranean. During
2016, a biweekly monitoring of phytoplankton assemblages
and the main abiotic factors were realized at three
representative stations. Taxonomic composition, abundance,
and diversity index were determined. In total,
227 phytoplankton species (160 diatoms and 53 dinoflagellates)
were inventoried. There was a clear dominance
of diatoms (62.9%) compared with dinoflagellates
(36.8%). Diatoms dominated in spring and
dinoflagellates developed in summer and early autumn
in Mellah showing a marked seasonal trend. Data
showed that the dynamic of the phytoplankton taxa
evolving in the lagoon was mainly driven by temperature and salinity. For the first time, a number of potentially toxic species have been identified, including 2diatoms (Pseudo-nitzschia group delicatissima, Pseudo-nitzschia group seriata) and 5 dinoflagellates(Alexandrium minutum, Alexandrium tamarense/catenella, Dinophysis acuminata, Dinophysis sacculus,Prorocentrum lima). These harmful species could threat the functioning of the Mellah lagoon and human health and require the establishment of a monitoring network. Finally, our study suggests that the observed decrease of the phytoplankton diversity between 2001 and 2016could result from the reduction in water exchanges between the lagoon and the adjacent coast following the gradual clogging of the channel.
Keywords Phytoplankton monitoring . Environmental conditions . Diversity. HAB species . Mediterranean lagoon

Information

Item Type:	Journal
Divisions:	» Laboratoire des Ecosystèmes Aquatiques et Terrestres » Faculté des Sciences de la Nature et de la Vie
ePrint ID:	1958
Date Deposited:	2019-10-17
Further Information:	Google Scholar
URI:	https://www.univ-soukahras.dz/fr/publication/article/1958

BibTex