Organic matter quantity and quality, metals availability and foraminiferal assemblages as environmental proxy applied to the Bizerte Lagoon (Tunisia). Issue 1 (15th April 2016)

• Record Type: Journal Article
• Authors: Martins, Maria Virgínia Alves; Helali, Mohamed Amine; Zaaboub, Noureddine; Boukef-BenOmrane, Imen; Frontalini, Fabrizio; Reis, Darlly; Portela, Helena; Clemente, Iara Martins Matos Moreira; Nogueira, Leandro; Pereira, Egberto; Miranda, Paulo; El Bour, Monia; Aleya, Lotfi
• Is Part Of: Marine pollution bulletin. Volume 105:Issue 1(2016:Apr.)
• Page Start: 161
• Page End: 179
• Publication Date: 2016-04-15
• Subjects: Living benthic foraminifera -- TOC -- Biopolymer concentrations -- Bacteria -- Chlorophyll a -- Simultaneously extracted metals -- Acid volatile sulfides -- Oxygen isotopes; Marine pollution -- Periodicals; Marine Biology -- Periodicals; Water Pollution -- Periodicals; Mer -- Pollution -- Périodiques; Publications périodiques; Pollution des mers; Lutte antipollution; Electronic journals; 363.7394
• DOI: 10.1016/j.marpolbul.2016.02.032
• Languages: English
• ISSNs: 0025-326X

Abstract

Abstract: This study analyzes the benthic trophic state of Bizerte Lagoon (Tunisia) based on the total organic matter and the bioavailability of biopolymeric carbon including proteins (PTN), carbohydrates (CHO), lipids (LIP), chlorophyll a, as well as bacteria counts. The overall simultaneously extracted metals (SEM), and acid volatile sulfides (AVS) as well as the SEM/AVS ratio indicative of the toxicity of the sediments also were analyzed aiming to study their impact in the dimension, composition and structure of both dead and living benthic foraminiferal assemblages. In the studied sites TOC content is relatively high and the PTN/CHO values indicate that they can be considered as meso-eutrophic environments. The CHO/TOC and C/N values suggest that the OM which accumulated on the sediments surface has mainly natural origin despite the introduction of municipal and industrial effluents in the lagoon and the large bacterial pool. The living assemblages of benthic foraminifera of Bizerte Lagoon are quite different to other Mediterranean transitional systems studied until now. They are composed of typical lagoonal species but also include several marine and opportunistic species including significant numbers of bolivinids, buliminids, Nonionella / Nonionoides spp. and Cassidulina / Globocassidulina spp. These assemblages seem to benefitfrom the physicochemical parameters and the sediment stability. They may however face environmental stress in the lagoon related to the AVS production as a result of the organic matter degradation and toxicity in some areas due to the available concentrations of metals. Nonetheless statistical results evidence that the structure and dimension of assemblages are being controlled mostly by OM quantity and quality related mainly to the availability of PTN, CHO and chlorophyll a . Results of this work support the importance of considering OM quantity and quality in studies of environmental impact in coastal systems. Highlights: An atypical Mediterranean lagoonal benthic foraminifera assemblage. Negative impact of metals and TOC on living benthic foraminifera. Bacterial pool related to pollution and microorganisms' relationship. Preference of some foraminifera species by different biopolymers. The importance of analyses of organic matter quality.