Browsing by Author "Pospelova V."

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    The dinoflagellate cyst genera Achomosphaera Evitt 1963 and Spiniferites Mantell 1850 in Pliocene to modern sediments: a summary of round table discussions
    (Taylor and Francis Inc., 2018) Mertens K.N.; Van Nieuwenhove N.; Gurdebeke P.R.; Aydin H.; Bogus K.; Bringué M.; Dale B.; De Schepper S.; de Vernal A.; Ellegaard M.; Grothe A.; Gu H.; Head M.J.; Heikkilä M.; Limoges A.; Londeix L.; Louwye S.; Marret F.; Masure E.; Matsuoka K.; Mudie P.J.; Penaud A.; Pospelova V.; Price A.M.; Ribeiro S.; Rochon A.; Sangiorgi F.; Schreck M.; Torres V.; Uzar S.; Versteegh G.J.M.; Warny S.; Zonneveld K.
    We present a summary of two round-table discussions held during two subsequent workshops in Montreal (Canada) on 16 April 2014 and Ostend (Belgium) on 8 July 2015. Five species of the genus Achomosphaera Evitt 1963 and 33 of the genus Spiniferites Mantell 1850 emend. Sarjeant 1970 occuring in Pliocene to modern sediments are listed and briefly described along with remarks made by workshop participants. In addition, several holotypes and topotypes are reillustrated. Three species previously assigned to Spiniferites are here considered/accepted as belonging to other genera: Impagidinium inaequalis (Wall and Dale in Wall et al. 1973) Londeix et al. 2009, Spiniferites? rubinus (Rossignol 1962 ex Rossignol 1964) Sarjeant 1970, and Thalassiphora balcanica Balteş 1971. This summary forms the basis for a set of papers that follows, where points raised during the workshops are explored in greater detail. © 2018, © 2018 The Author(s). Published by AASP–The Palynological Society.
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    A review of rare, poorly known, and morphologically problematic extant marine organic-walled dinoflagellate cyst taxa of the orders Gymnodiniales and Peridiniales from the Northern Hemisphere
    (Elsevier B.V., 2020) Mertens K.N.; Gu H.; Gurdebeke P.R.; Takano Y.; Clarke D.; Aydin H.; Li Z.; Pospelova V.; Shin H.H.; Li Z.; Matsuoka K.; Head M.J.
    Dinoflagellates are a major component of the modern plankton. Of the 2192 species of marine free-living dinoflagellates presently described, an increasing number are being shown to produce resting cysts (probably hypnozygotes) within their life cycle. With rare exception, only the resting cysts fossilize, so they are of central importance in tracing the history of dinoflagellates through geological time. Cysts of many of the more common dinoflagellate species have distinctive morphologies allowing their geographic and stratigraphic occurrences to be traced. An ever-increasing number of taxa are also being shown to produce distinctive and geologically preservable cysts, potentially enhancing our knowledge of the diverse representation of dinoflagellates through time. Here the organic-walled cysts of 73 rare, poorly known or morphologically problematic marine dinoflagellate cyst species belonging to the orders Gymnodiniales (nine species) and Peridiniales (64 species) are reviewed, described and illustrated, and their stratigraphic ranges assessed. The names Echinidinium aculeatum and Echinidinium transparantum are validated. © 2019 Elsevier B.V.
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    Environmental factors influencing the abundance and spatial distribution of modern dinoflagellate cysts in Izmir Bay (Eastern Mediterranean)
    (Elsevier Ltd, 2024) Aydin H.; Uzar S.; Cingöz E.E.; Küçüksezgin F.; Pospelova V.
    We analyzed surface sediments from 12 stations located in Izmir Bay to determine the impact of anthropogenic pollution on dinoflagellate cysts. Forty-three dinoflagellate cyst taxa and two cyst assemblage zones were identified. Zone 1 is characterized by the dominance of cysts of Gymnodinium nolleri, Selenopemphix nephroides, and Operculodinium centrocarpum from the oligotrophic part of Izmir Bay. Zone 2 is in the highly productive inner part of the bay and is characterized by the high abundances of Lingulodinium machaerophorum, Spiniferites ramosus, cysts of Scrippsiella spp., cysts of Polykrikos spp. and Quinquecuspis concreta. We used multivariate statistical analysis (DCA and CCA) on dinoflagellate cysts and environmental variables to support the identification of Zones 1 and 2. Our analyses also revealed that summer and winter chlorophyll-a as well as elevated nitrate and nitrite concentrations are significant parameters in controlling dinoflagellate cyst distribution in Izmir Bay. © 2024 Elsevier Ltd