L. and Voronina, E. 2001. Dinoflagellate cyst assemblages as tracers of sea-surface conditions in the northern North Atlantic, Arctic and sub-Arctic seas: the new 'n = 677' data base and its application for quantitative palaeoceanographic reconstruction.ABSTRACT: The distribution of dinoflagellate cyst (dinocyst) assemblages in surface sediment samples from 677 sites of the northern North Atlantic, Arctic and sub-Arctic seas is discussed with emphasis on the relationships with sea-surface parameters, including sea-ice cover, salinity and temperature of the coldest and warmest months. Difficulties in developing a circum-Arctic data base include the morphological variation within taxa (e.g. Operculodinium centrocarpum, Islandinium? cezare and Polykrikos sp.), which probably relate to phenotypic adaptations to cold and/or low salinity environments. Sparse hydrographical data, together with large interannual variations of temperature and salinity in surface waters of Arctic seas constitute additional limitations. Nevertheless, the use of the best-analogue technique with this new dinocyst data base including 677 samples permits quantitative reconstruction of sea-surface conditions at the scale of the northern North Atlantic and the Arctic domain. The error of prediction calculated from modern assemblages is ±1.3°C and ±1.8°C for the temperature of February and August, respectively, ±1.8 for the salinity, and ±1.5 months yr −1 for the sea-ice cover. Application to late Quaternary sequences from the western and eastern subpolar North Atlantic (Labrador Sea and Barents Sea) provide reconstructions compatible with those obtained using the previous dinocyst data base (n = 371), which mainly included modern data from the northern North Atlantic.

Palynomorphs were analysed in two sediment cores from the southeastern Barents Sea representing the past 8.3 and 4.4 kyr. High dinocyst contents and species diversity enabled the application of the best analogue method to quantitatively reconstruct sea-surface salinities, temperatures and ice cover using 677 modern reference sites from the North Atlantic and Arctic seas, including new data from the Barents Sea reported here. At the southern core site, where waters are affected by the Atlantic inflow, sea-surface conditions were relatively warm and stable between ca. 8000 and 5000 calendar yr BP. In contrast, the past 5 kyr had periods with cooler temperatures and extended ice cover, fluctuating mostly at 1-1.5 kyr frequencies at both sites. Most pronounced coolings occurred around 8.1, 5, 3.5-3.2 and 2.5 ka. The northern site additionally shows younger cooling events, tentatively dated to 1.4, 0.3 and 0.1 ka. Identified variations in seasurface conditions indicate changes in Atlantic water inputs to the Barents Sea. Our results generally correlate to palaeoclimatic reconstructions from northwestern Eurasia, exemplified by palynological records from Karelia. This correlation suggests that sea-surface variations in the Barents Sea reflect large-scale changes in atmospheric and oceanic interactions between the North Atlantic and the Arctic.

Voronina, E.P. and Hughes, D.R. 2011. Types and development pathways of lateral line scales in some teleost species. —Acta Zoologica (Stockholm) 00: 1–13. A comparative study of lateral line scales (lls) in nine teleost species was undertaken to trace their ontogenetic structural changes. Three universal characters were used to describe and classify definitive and developing lls. The four main structural types in teleosts are represented. In adult fish, lls are the same structural type in all parts of lateral line in any one specimen, but number of tubules and their orientation may vary. In juvenile fish, except for one species, the structural type of every lls changes with growth, and this process progresses along the lateral line in the direction of development typical for the species. Definitive structural type of the lls is not determined by common scale type and size, presence or absence of nerve foramen on lls, scale overlapping or time of initiation of scales and trunk canal. Development pathways are proposed in which terminal states correspond to the final development of the most complex lls type in Cyprinus carpio, Carassius carassius, Oncorhynchus mykiss, Diplodus annularis and Mullus barbatus. The intermediate states of these pathways correspond to other types of lls as examples of pedomorphosis in Perca fluviatilis, Sander lucioperca, Symphysodon aequifasciatus and Hippoglossoides platessoides.

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