Samples from coastal tropical waters of Central Sulawesi, Bangka Island and Bawean Island in Indonesia and from the Great Barrier Reef at Fitzroy Island in Queensland, Australia were analysed for species composition of diatom assemblages with a focus on Olifantiella. Whereas samples from Fitzroy Island littoral in Australia retrieved only one species of Olifantiella, in Poso Bay, Indonesia, we observed at least six species. All established taxa were documented with light (LM) and scanning electron microscope (SEM) and principal component analysis (PCA) analysis was used to compare the species, based on the basic valve parameters of length, width, length to width ratio and striae density. A new species of the genus Olifantiella, O. gondwanensis is described from Australia. In addition, we showed the distinct nature of O. pilosella var. rhizophorae permitting to species status. Particular attention is placed on girdle bands in this genus.

A water sample was obtained from an arheic oasis in the deep Sahara Desert, the Gueltates Afilal in Tamanrasset (Algeria). Five diatom strains were isolated, cultivated and identified as Tryblionella apiculata, Nitzschia supralitorea, Fistulifera saprophila, Navicula veneta and Thalassiosira pseudonana using a combination of scanning electron microscopy and next generation sequencing. The diatoms identified are opportunistic and cosmopolitan species with known tolerances to organic pollution and variations in salinities, often found in meso- and polysaprobic zones in Europe. Their complete organellar genomes have been sequenced and some exhibit features never observed among diatoms before. To our knowledge this is the first time that living specimens of diatoms from the deep Sahara are identified using modern taxonomical tools in the frame of a study which also demonstrates the possibility to cultivate such material in laboratories for further experiments on biogeography and bioindication. Our study also suggests that European identification keys can be effective when employed on diatoms from the Sahara.

Palaeoenvironmental reconstructions can provide important information into the processes influencing the long-term development of the Baltic Sea since the Last Glacial Maximum. This paper uses lithological and diatomological evidence from two sediment cores to reconstruct the palaeoenvironments of the mouth of the Rega Valley, Poland. We use the ecological preferences of diatoms to qualitatively reconstruct changes in salinity over the same period. Results between the two cores correspond, and demonstrate that both basins have experienced a series of marine transgressions, coastal aggradation, and lagoon development over the Late Glacial and Holocene. Surprisingly, our high-resolution core profiles demonstrate that conditions varied between fresh brackish and brackish fresh for most of the Holocene (Boreal through Subatlantic Chronozones), whilst the well-documented mid-Holocene peak in salinities between 6.000 and 5.000 cal. BP was not observed in our records. It is likely that this indicates the buffering of the Baltic waters from freshwaters from the south, and demonstrates the importance of terrestrial-hydrological processes for determining the long-term stability of the salinities in the southern Baltic coastal zone.

ABSTRACT Witkowski, A.; Li, C. L.; Zg[lstrok]obicka, I.; Yu, S. X.; Ashworth, M.; Dąbek, P.; Qin, S.; Tang, C.; Krzywda, M.; Ruppel, M.; Theriot, E. C.; Jansen, R. K.; Car, A.; Płociński, T.; Wang, Y. C.; Sabir, J. S. M.; Daniszewska-Kowalczyk, G.; Kierzek, A., and Hajrah, N. H., 2016. Multigene assessment of biodiversity of diatom (Bacillariophyceae) assemblages from the littoral zone of the Bohai and Yellow Seas in Yantai region of Northeast China with some remarks on ubiquitous taxa. Diatoms are important contributors to the benthic microeukaryote flora. This manuscript lays the foundation for future metagenomic and environmental sequencing projects off coastal China by curating diatom DNA sequences from the Yantai region of the Bohai and Yellow Seas (Northeast China). These studies are based on cultures established from samples collected in different seasons from marine littoral and supralittoral zones in 2013 and 2014. Thirty-six diatom strains were cultured successfully and identification of these clones was determined by light and scanning electron microscopy(LM and SEM) and DNA sequencing of the nuclear-encoded small subunit ribosomal RNA (SSU)and chloroplast-encoded rbcL and psbC genes. The strains primarily represent raphid pennate genera, such as Amphora, Amphora (Oxyamphora), Caloneis, Diploneis, Halamphora, Navicula, Nitzschia, Parlibellus, Pleurosigma, Surirella and Tryblionella. When the DNA markers from these strains were analysed in a multi-gene phylogeny, we found that some clones-particularly within the genera Amphora, Navicula and Nitzschia—show greater than expected genetic diversity despite their very similar morphology and morphometrics. We also compared the molecular and morphological identities of several seemingly ubiquitous marine littoral taxa in the genera Amphora and Nitzschia from the Indian Ocean and Atlantic Ocean, the Red Sea and Adriatic Sea to their Yellow Sea counterparts.

The diatom flora from a high-resolution core collected from Disko Bugt, central West Greenland, records variations in surface water temperature for the late Holocene (1600-300 cal. BP). Our data support the existence of a previously identified anti-phase relationship between the surface water temperature from West Greenland and climate events recorded in the NE Atlantic and between surface and subsurface waters (identified from benthic foraminifera) of the West Greenland Current (WGC). The diatom flora record relatively cool surface water conditions during the end of the 'Roman Warm Period' and 'Medieval Warm Period' (MWP), and relatively warmer surface water conditions during the 'Dark Ages Cold Period' and 'Little Ice Age' (LIA). This is particularly pronounced during the MWP, experiencing the coldest conditions, and the LIA experiencing the warmest conditions through the whole sequence studied. The most likely explanation for this anti-phase relationship is linked to the flux of meltwater delivered to the WGC from sea ice and the Greenland ice sheet off the West Greenland margin. The generally warmer conditions of the MWP resulted in increased melting of sea ice and the Greenland ice sheet producing an increased meltwater flux and cooling of the surface waters of the WGC. In contrast, reduced meltwater flux during the relatively cold LIA resulted in reduced meltwater flux to the WGC, producing a relative warming of the surface waters recorded by the diatom flora.

This study focuses on diatom assemblages occurring in cores of Late-glacial and Holocene deposits retrieved from the mouth of the lower Rega River valley, of the southern coast of the Baltic Sea. Sediment samples from four cores were the subject of the present study. Diatom-inferred environmental characteristics, e.g., water level; water salinity (conductivity), trophic status and pH, within each core are presented. Diatom assemblage zones (DAZ) were distinguished, based on differences in the distribution of particular ecological groups. Each DAZ appears to be related to environmental changes during the deposition of a given sediment interval. The Late-glacial (Allerod) sediments originated in a shallow lake with increasing concentrations of solutes and nutrients. The Holocene record begins in the early Atlantic Chronozone and the diatoms point to weakly brackish-water sediments deposited in a shallow water environment. During the period of 8,500-5,800 cal year BP sedimentation took place in a shallow embayment and/or lagoon. From ca. 5,800 cal year BP onwards sedimentation took place in a peat bog environment alternating with Aeolian deposition. Changes in diatom community structure imply a close relationship with the climate-controlled eustatic rise of the ocean level and its consequence Littorina transgression. As with other southern Baltic Sea localities, brackish-water diatoms appear in the sediments, signaling the onset of marine transgression somewhat earlier than previously accepted. Differences and similarities in diatom assemblages and the palaeogeographic development of nearby regions within the Baltic Sea basin and lagoons (coastal areas) from different geographic regions, are also discussed.