Microbial sedimentary imprint on the deep Dead Sea sediment. (6th June 2016)

• Record Type: Journal Article
• Authors: Thomas, Camille; Ebert, Yael; Kiro, Yael; Stein, Mordechai; Ariztegui, Daniel
• Is Part Of: Depositional record. Volume 2:Number 1(2016)
• Page Start: 118
• Page End: 138
• Publication Date: 2016-06-06
• Subjects: EPS -- geomicrobiology -- hypersaline -- iron‐sulphur mineralization; Sediments (Geology) -- Periodicals; Sedimentology -- Periodicals; Sedimentation and deposition -- Periodicals; 552.5
• DOI: 10.1002/dep2.16
• Languages: English
• ISSNs: 2055-4877

Abstract

Abstract: A study of an International Continental Drilling Program core recovered from the middle of the modern Dead Sea has identified microbial traces within this subsurface hypersaline environment. A comparison with an active microbial mat exhibiting similar evaporative processes characterized iron‐sulphur mineralization and exopolymeric substances resulting from microbial activity. Exopolymeric substances were identified in the drilled sediment but unlike other hypersaline environments, it appears that they have a limited effect on the precipitation of calcium carbonate in the sedimentary column. Sulphate reduction, however, plays a role in all types of evaporative facies, leading to the formation of diagenetic iron sulphides in glacial and interglacial intervals. Their synthesis seems to occur under progressive sulphidation that generally stops at greigite because of incomplete sulphate reduction. The latter may be caused by a lack of suitable organic matter in this hypersaline, hence energy‐demanding, environment. Pyrite may be found in periods of high lake productivity, when more labile organic matter is available. The carbon and sulphur cycles are thus influenced by microbial activity in the Dead Sea environment and this influence results in diagenetic transformations in the deep sediment. Abstract : This paper presents a record of iron‐sulphur mineralization and other biosignatures significative of microbial activity in the Dead Sea sediment. Based on microbial mat and deep drilling sedimentary information, it outlines the impact of microbial communities on the sulphur and carbon cycles, as well as on the magnetic record in the deep sediment of the hypersaline Dead Sea.