Geomorphology of the Coastal Sand Dune Fields and Their Association with the Palaeolandscape Evolution of Akrotiri Peninsula, Lemesos, Cyprus

Two well-developed late Pleistocene dune fields have been identified on the western and eastern side of Akrotiri promontory (Lemesos, Cyprus). The dune fields extend immediately from the low level of their source beaches onto higher ground (>48 m amsl). Geomorphic observations supported by OSL dating and sedimentological data provided evidence of the dune development and for the palaeogeographic reconstruction of the area. Relative sea level changes and wave action during the upper Pleistocene and Holocene played an important role into the development of the palaeolandscape and affected the formation of the dunes. From the collected data the development of the western dune field started at 56.2 ± 5.5 ka when the relative sea level was at approximately −60 m and contributed to the development of the western tombolo of the area whereas the eastern dune field developed in the late Holocene, after the formation of the eastern spit that resulted in the formation of the Akrotiri Salt lake.

The late Quaternary stratigraphy of coastal dunes and associated deposits in southern Africa

Coastal sand dune sediments with associated intraformational aeolianite, palaeosols and beachrock are found throughout much of the southern African coast, and have important roles as both Quaternary environmental archives and in recording the interplay of sediment supply, coastal processes and sea-level change. This paper examines the stratigraphy and palaeoenvironmental significance of coastal sand dunes and associated sediments, using examples mainly from South Africa but also with reference to the sandy coasts of Namibia and southern Mozambique. Based on morphological, sedimentary and dating evidence reported in the diverse literature, the stratigraphic relationship of coastal sand dune sediments to Marine Isotope Stages (MIS) is summarized, and a chronostratigraphic diagram for the period MIS 6 to 1 along the South African coast is used to identify spatially coherent sedimentary units that correspond to different regional climatic and sea-level phases. This framework provides a stratigraphic context to better examine the relationship between coastal sand dunes and external forcing during the late Quaternary in southern Africa, and to guide future field studies.

Hymenobacter Taeanensis Sp. Nov., Radiation Resistant Bacterium Isolated from Coastal Sand Dune

An aerobic, Gram-stain-negative, non-motile, non-spore-forming, rod-shaped, and light pink-colored bacterial strain, designated TS19T, was isolated from a sand sample obtained from a coastal sand dune after exposure to 3 kGy of gamma radiation. Phylogenetic analysis based on the 16S rRNA gene sequences revealed that the isolate was a member of the genus Hymenobacter and was most closely related to H. wooponensis WM78T (98.3% similarity). Strain TS19T and H. wooponensis showed resistance to gamma radiation with D10 values (i.e., the dose required to reduce the bacterial population by tenfold) of 7.3 kGy and 3.5 kGy, respectively. The genome of strain TS19T consists of one contig with 4,879,662 bp and has a G+C content of 56.2%. The genome contains 3,955 protein coding sequences, 44 tRNAs, and 12 rRNAs. The predominant fatty acids of strain TS19T were iso-C15:0, summed feature 4 (iso-C17:1 I and/or anteiso-C17:1 B), summed feature 3 (C16:1 ω6c and/or C16:1 ω7c), and C16:1 ω5c. The major polar lipids were phosphatidylethanolamine, and one unknown aminophospholipid. The main respiratory quinone was menaquinone-7. Based on the phylogenetic, physiological, and chemotaxonomic characteristics, strain TS19T represents a novel species, for which the name Hymenobacter taeanensis sp. nov. is proposed. The type strain is TS19T (=KCTC 72897T =JCM 34023T).

Arenibacterium halophilum gen. nov., sp. nov., a halotolerant bacterium in the family Rhodobacteraceae isolated from a coastal sand dune

A Gram-stain-negative, non-pigmented, non-spore-forming, motile, strictly aerobic bacterial strain, designated CAU 1492T, was isolated from a coastal sand dune and its taxonomic position was examined using a polyphasic approach. Cells of strain CAU 1492T grew optimally at 30 °C, pH 7.0 and in 3 % (w/v) NaCl. Phylogenetic analysis based on the 16S rRNA gene sequence of CAU 1492T showed that it formed a distinct lineage within the family Rhodobacteraceae as a separate deep branch, with 96.8 % or lower sequence similarity values to representatives of the genera Marivita , Donghicola , Sulfitobacter , Marinovum , Phaeobacter , Primorskyibacter , Roseovarius and Aestuariihabitans . Strain CAU 1492T was closely related to Marivita geojedonensis DPG-138T (96.8 %), Donghicola eburneus SW-277T (96.7 %), Sulfitobacter porphyrae SCM-1T (96.7 %), Marinovum algicola FF3T (96.6 %) and Aestuariihabitans beolgyonensis BB-MW15T (96.4 %) based on 16S rRNA gene sequences. The major cellular fatty acids of strain CAU 1492T were cyclo-C19 : 0 ω8c and summed feature 8 (C18 : 1 ω7c/C18 : 1 ω6c). The polar lipid pattern was composed of phosphatidylglycerol, phosphatidylethanolamine, an unidentified phospholipid and an unidentified aminolipid. The strain contained Q-10 as the sole respiratory quinone. The draft genome of strain CAU 1492T was 4.63 Mb with a DNA G+C content of 63.1 mol%. The genome includes 4292 protein-coding genes and a five rRNA operons. On the basis of the phenotypic, chemotaxonomic and genomic data, strain CAU 1492T represents a novel genus in the family Rhodobacteraceae for which the name Arenibacterium halophilum gen. nov., sp. nov. is proposed. The type strain of Arenibacterium halophilum is CAU 1492T (=KCTC 62998T=NBRC 113696T).