title: Lipid biomarkers, pigments and cyanobacterial diversity of microbial mats across intertidal flats of the arid coast of the Arabian Gulf (Abu Dhabi, UAE).
abstract: Variations in morphology, fatty acids, pigments and cyanobacterial community composition were studied in microbial mats across intertidal flats of the arid Arabian Gulf coast. These mats experience combined extreme conditions of salinity, temperature, UV radiation and desiccation depending on their tidal position. Different mat forms were observed depending on the topology of the coast and location. The mats contained 63 fatty acids in different proportions. The increased amounts of unsaturated fatty acids (12-39%) and the trans/cis ratio (0.6-1.6%) of the cyanobacterial fatty acid n-18:1omega9 in the higher tidal mats suggested an adaptation of the mat microorganisms to environmental stress. Chlorophyll a concentrations suggested lower cyanobacterial abundance in the higher than in the lower intertidal mats. Scytonemin concentrations were dependent on the increase in solar irradiation, salinity and desiccation. The mats showed richness in cyanobacterial species, with Microcoleus chthonoplastes and Lyngbya aestuarii morphotypes as the dominant cyanobacteria. Denaturing gradient gel electrophoresis patterns suggested shifts in the cyanobacterial community dependent on drainage efficiency and salinity from lower to higher tidal zones. We conclude that the topology of the coast and the variable extreme environmental conditions across the tidal flat determine the distribution of microbial mats as well as the presence or absence of different microorganisms.
authors.affiliation: Max Planck Institute for Marine Microbiology, Bremen, Germany.
authors.forename: Raeid M M
authors.initials: RM
authors.lastname: Abed
authors.forename: Katharina
authors.initials: K
authors.lastname: Kohls
authors.forename: Raphaela
authors.initials: R
authors.lastname: Schoon
authors.forename: Ann-Kathrin
authors.initials: AK
authors.lastname: Scherf
authors.forename: Marion
authors.initials: M
authors.lastname: Schacht
authors.forename: Katarzyna A
authors.initials: KA
authors.lastname: Palinska
authors.forename: Huda
authors.initials: H
authors.lastname: Al-Hassani
authors.forename: Waleed
authors.initials: W
authors.lastname: Hamza
authors.forename: Jürgen
authors.initials: J
authors.lastname: Rullkötter
authors.forename: Stjepko
authors.initials: S
authors.lastname: Golubic
mesh_terms: D044822:Biodiversity; D000458:Cyanobacteria / Q000737:chemistry* / Q000166:cytology / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics; D003681:Dehydration; D016521:Electrophoresis, Gel, Pulsed-Field; D005227:Fatty Acids / Q000737:chemistry*; D005798:Genes, Bacterial; D020459:Genes, rRNA; D007211:Indoles / Q000737:chemistry; D008027:Light; D008853:Microscopy; D008969:Molecular Sequence Data; D010636:Phenols / Q000737:chemistry; D010802:Phylogeny; D010860:Pigments, Biological / Q000737:chemistry*; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D054712:Salinity; D012623:Seawater / Q000382:microbiology; D014466:Ultraviolet Rays; D014479:United Arab Emirates; D014871:Water Microbiology
chemical_list: D004269:DNA, Bacterial; D005227:Fatty Acids; D007211:Indoles; D010636:Phenols; D010860:Pigments, Biological; D012336:RNA, Ribosomal, 16S; C083368:scytonemin