Universität zu Köln

Ben Hamad, Asma, Viehberg, Finn A., Khadraoui, Afef, Zaibi, Chahira, Trabelsi, Yasser, Mouanga, Gloria H., Langer, Martin R., Abida, Habib and Kamoun, Fekri (2018). Water level and atmospheric humidity history of Lake Ichkeul (northern Tunisia) during the last 3000 years. Arab. J. Geosci., 11 (12). HEIDELBERG: SPRINGER HEIDELBERG. ISSN 1866-7538

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Abstract

Changes in paleoecology and climate of northern Tunisia during the last 3000 years were reconstructed based on the flood history interpreted from a 172-cm sediment core of Lake Ichkeul (NW Tunisia). Seven wet/dry episodes were identified based on biological (ostracods, foraminifera and mollusks) and biotic indices (H and E index, species richness and abundance). These proxy-based environmental changes were supported by correspondence analyses (CAs) and ecophenotypic responses of the brackish taxon Cyprideis torosa in addition to a grain-size study. Two dry episodes were identified in the lower (EP1) and upper (EP7) parts of the core. These were marked by the dominance of the brackish ostracod C. torosa. High water salinity was indicated by the presence of the brackish ostracod Loxoconcha elliptica, the foraminifer Ammonia sp. and lagoonal mollusks. The occurrence of the freshwater ostracods Ilyocypris sp., Herpetocypris sp., Dawinula stevensoni and Limnocythere inopinata was associated with high species richness and ecophenotypic changes of C. torosa valves indicating lower salinity during three major wet episodes (EP2, EP4, and EP6). The ecological and environmental changes, occurring between 3050 and 50 cal. year BP, are most likely linked to an increase of fluvial inputs which are also recognized in several other Mediterranean lakes. The humid episodes were interrupted by two saline periods (EP3 and EP5) during which freshwater ostracod assemblages declined, diversity indices dropped to the lowest values, and fine-grained sediments became dominant. The top of the core is characterized by the remarkable dominance of L. elliptica coupled with C. torosa, the absence of freshwater ostracods, and the changes in grain-size sediment parameters which are most likely the result of anthropogenic activities. The changes in hydrochemistry and sedimentology were attributed to the deepening of the Bizerte navigation canal, main wadis damming, and Tinja sluice construction which mostly occurred in the XXth century.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Ben Hamad, Asma UNSPECIFIED UNSPECIFIED UNSPECIFIED Viehberg, Finn A. UNSPECIFIED UNSPECIFIED UNSPECIFIED Khadraoui, Afef UNSPECIFIED UNSPECIFIED UNSPECIFIED Zaibi, Chahira UNSPECIFIED UNSPECIFIED UNSPECIFIED Trabelsi, Yasser UNSPECIFIED UNSPECIFIED UNSPECIFIED Mouanga, Gloria H. UNSPECIFIED UNSPECIFIED UNSPECIFIED Langer, Martin R. UNSPECIFIED UNSPECIFIED UNSPECIFIED Abida, Habib UNSPECIFIED UNSPECIFIED UNSPECIFIED Kamoun, Fekri UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-184367
DOI:	10.1007/s12517-018-3678-0
Journal or Publication Title:	Arab. J. Geosci.
Volume:	11
Number:	12
Date:	2018
Publisher:	SPRINGER HEIDELBERG
Place of Publication:	HEIDELBERG
ISSN:	1866-7538
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language GARAET EL ICHKEUL; CYPRIDEIS-TOROSA; FORAMINIFERAL ASSEMBLAGES; BENTHIC FORAMINIFERA; ENVIRONMENTAL-CHANGE; NONMARINE OSTRACODA; LATE QUATERNARY; CLIMATE-CHANGE; GRAIN-SIZE; HOLOCENE Multiple languages Geosciences, Multidisciplinary Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/18436