73 research outputs found

    Распространение копепод в Эгейском море в марте 2012 года

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    Исследовано горизонтальное и вертикальное распределение копепод на основе зоопланктонных проб, собранных в марте 2012 года на 10 станциях в Эгейском море. 83 вида копепод были идентифицированы. Они доминировали в зоопланктонном сообществе почти на всех станциях. Более 70% копепод были обнаружены в верхнем 100-метровом слое воды. С помощью кластерного анализа выделены пять групп проб, различающихся распределением взрослых и личиночных стадий копепод и гидрологическими характеристиками.Horizontal and vertical distributions of copepods were investigated based on zooplankton samples collected during March 2012 at 10 stations in Aegean Sea. A total of 83 copepod species were identified. Copepods dominated the zooplankton assemblages at almost all stations. More than 70% of copepods were found in the upper 100 m layer. Using cluster analysis, five groups of samples differing on distribution of adult and copepodite stages of copepods and hydrological characteristics were determined

    Nutrient exchange fluxes between the Aegean and Black Seas through the Marmara Sea

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    Long-term data obtained in the Turkish Strait System (TSS) including the Sea of Marmara, the Dardanelles and Bosphorus straits, during 1990-2000, have permitted us to calculate seasonal and annual fluxes of water and nutrients (nitrate, phosphate) exchanged between the Aegean and Black Seas through the TSS. Two-layer flow regimes in the TSS introduce the brackish waters of the Black Sea into the Aegean basin of the northeastern Mediterranean throughout the year. A counter flow in the TSS carries the salty Mediterranean water into the Black Sea via the Marmara deep basin. The annual volume influx from the Black Sea to the Marmara upper layer is nearly two-fold the salty water exported from the Marmara to the Black Sea via the Bosphorus underflow. The brackish Black Sea inflow is relatively rich in nitrate and phosphate in winter, decreasing to the lowest levels in late summer and autumn. Biologically labile nutrients of Black Sea origin are utilized in photosynthetic processes in the Marmara Sea and are partly exported to the Marmara lower layer. Eventually, the brackish Black Sea waters reach the Dardanelles Strait, with modified bio-chemical properties. On the other hand, the salty Mediterranean waters with low concentrations of nutrients enter the Marmara deep basin. During threir 6-7 year sojourn in the Marmara basin, the salty waters become enriched in nitrate (DIN) and phosphate (DIP), due to oxidation of planktonic particles sinking from the Marmara surface layer. The annual nutrient inputs from the Black Sea to the Marmara basin were estimated as 8.17x108 moles of DIN and 4.25x107 moles of DIP, which are much less than the importation from the Marmara lower layer via the Bosphorus undercurrent. The salty Aegean water introduces nearly 6.13x108 moles of DIN and 2.79x107 moles of DIP into the Marmara lower layer. The estimated DIP outflux from the Aegean Sea is nearly 2 times less than the importation from the Marmara Sea via the Dardanelles Strait

    The distribution of Pseudodiaptomus marinus in European and neighbouring waters —A rolling review

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    Among non-native copepods, the calanoid Pseudodiaptomus marinus Sato, 1913 is the species probably spreading at the fastest pace in European and neighbouring waters since its first record in the Adriatic Sea in 2007. In this contribution, we provide an update on the distribution of P. marinus in the Mediterranean and Black Seas, along the Atlantic coasts of Europe, in the English Channel and in the southern North Sea. Starting from a previous distribution overview, we include here original and recently (2019–2023) published data to show the novel introduction of this species in different geographical areas, and its secondary spreading in already colonised regions. The picture drawn in this work confirms the strong ability of P. marinus to settle in environments characterised by extremely diverse abiotic conditions, and to take advantage of different vectors of introduction. The data presented allow speculations on realistic future introductions of P. marinus and on the potential extension of its distribution rang

    Trophic Relationships and Food Supply of Heterotrophic Animals in the Pelagic Ecosystem of the Black Sea

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    During recent decades, the Black Sea has been affected by many negative factors that strongly changed the condition of its ecosystem. Especially trophic relationships in the Black Sea pelagic system became very vulnerable influencing the food supply, productivity and abundance of many species and populations of this marine basin. Food is one of most important link between biota and its environment. In this monograph, the role and variability of trophodynamic processes that effect the well-being (health) of main heterotrophic components of ecosystem were analysed in detail for a few key species as indicators for estimation of ecosystem condition in whole. These are most significant mass species of the Black Sea pelagic ecosystem. Among copepods this is Calanus euxinus that dominates the mesozooplankton which makes up the fodder base of planktivorous fishes. Among gelatinous these are medusa Aurelia aurita and the alien ctenophores Mnemiopsis leidyi and Beroe ovata which affected strongly mesozooplankton composition. Lastly among fishes the anchovy Engraulis encrasicolus ponticus and sprat Sprattus sprattus phalericus that dominate small pelagic fishery. We considered in this monograph: • Diel feeding behaviour, in situ feeding rate of Calanus euxinus and impact of mesozooplankton on primary production and phytoplankton biomass. • The effect of vertical migrations on energy budget and its components in C. euxinus; metabolic substrates used in catabolic processes under both aerobic and hypoxic conditions, the role of reserve lipids and effect of abiotic factors on individual growth and population structure of this species. • The intensity and efficiency of ingestion and energy transformation in three gelatinous species ( jellyfish Aurelia aurita, ctenophores Mnemiopsis leidyi and Beroe ovata) and their predatory impact on zooplankton community. • Nutritional condition and food supply of anchovy and sprat in the close interaction with natural biotic and abiotic and anthropogenic factors. • Tendencies in this interaction during long time space: since 1960 s till present years. • Estimation of population condition of these species and its long-term change. This monograph is the collective work of Ukrainian and Turkish scientists studying complex hydrobiological problems of the Black Sea. Its aim is to reveal the significance of nutritional factors on the ecology of Black Sea biota, including changes which have already occurred, as well as offering some insight into changes that may happen in the future. Our joint investigations started in the first half of the 1990s, when conditions for the close cooperation of researchers from the two countries were suitable after the collapse of the Soviet era. This spirit continues to the present day. Professor Ümit Unluata, Director of Erdemli Institute of Marine Sciences (Middle East Technical University, Ankara) was of paramount importance in organising and fostering the work undertaken. We would like to devote this monograph to the memory of him, who died so prematurely. We are also grateful to Academician Professor V. N. Eremeev, Director of the Sevastopol Institute of Biology of the Southern Sea (National Academy of Sciences of Ukraine), and to the directors of Erdemli Institute of Marine Sciences (Professor Ilkay Salihoglu, Professor Sukru Besiktepe and Professor Ferit Bingel) who also made significant contributions to the Ukrainian–Turkish collaboration. We are grateful to Dr Bill Parr from the Black Sea Ecosystem Recovery Project for his valuable efforts in improving earlier drafts. All these investigations were carried out within the framework of the following five NATO linkage-grants: • Pelagic animal food supply in the unstable Black Sea environment, • Will the new alien ctenophore Beroe ovata control the plankton community in the Black Sea? • Grazing, growth and production of Calanus euxinus in the Black Sea, • Bioindicators for assessment of Black Sea ecosystem recovery, • Adaptability and vulnerability of marine species in changing environments. And four TUBITAK - NASU joint projects: • Quantification of the recent ctenophore invader Beroe ovata impact in the Black Sea • Monitoring of the Black Sea anchovy and sprat, • Salinity tolerance as a key factor of invasion success of the copepods of Calanus genus into the Sea of Marmara, • Salinity tolerance as a key factor of invasion success of the mesozooplankton species into the Sea of Marmara. We hope that this publication will make a substantial contribution to future studies of the Black Sea ecosystem and offers further understanding of those features regulating biological processes in this unique marine basin

    Extensive cross-disciplinary analysis of biological and chemical control of Calanus finmarchicus reproduction during an aldehyde forming diatom bloom in mesocosms

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    Egg and faecal pellet production and egg hatching success of the calanoid copepod Calanus finmarchicus were monitored over a period of 14 days (14-28 April, 2008) while fed water from 4 differently treated mesocosms and ambient water. Two of the mesocosms used were inoculated with the polyunsaturated aldehyde (PUA)-producing diatom Skeletonema marinoi, while 2 received only nutrient additions with or without silica. The mesocosms developed blooms of S. marinoi, mixed diatoms or the haptophyte Phaeocystis pouchetii, respectively. Faecal pellet production of C. finmarchicus increased with increasing food availability. Egg production increased with time in all mesocosms to a maximum single female production of 232 eggs female(-1) day(-1) (average of 90 eggs female(-1) day(-1)) and followed the development of ciliates and P. pouchetii, but was not affected by the observed high (up to 15 nmol L(-1)) PUA production potential of the phytoplankton. The hatching success of the eggs produced on the mesocosm diets was high (78-96%) and was not affected by either aldehydes in the maternal diet or exposure to the dissolved aldehydes in the water

    Pseudo-nitzschia physiological ecology, phylogeny, toxicity, monitoring and impacts on ecosystem health

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    This paper is not subject to U.S. copyright. The definitive version was published in Harmful Algae 14 (2012): 271-300, doi:10.1016/j.hal.2011.10.025.Over the last decade, our understanding of the environmental controls on Pseudo-nitzschia blooms and domoic acid (DA) production has matured. Pseudo-nitzschia have been found along most of the world's coastlines, while the impacts of its toxin, DA, are most persistent and detrimental in upwelling systems. However, Pseudo-nitzschia and DA have recently been detected in the open ocean's high-nitrate, low-chlorophyll regions, in addition to fjords, gulfs and bays, showing their presence in diverse environments. The toxin has been measured in zooplankton, shellfish, crustaceans, echinoderms, worms, marine mammals and birds, as well as in sediments, demonstrating its stable transfer through the marine food web and abiotically to the benthos. The linkage of DA production to nitrogenous nutrient physiology, trace metal acquisition, and even salinity, suggests that the control of toxin production is complex and likely influenced by a suite of environmental factors that may be unique to a particular region. Advances in our knowledge of Pseudo-nitzschia sexual reproduction, also in field populations, illustrate its importance in bloom dynamics and toxicity. The combination of careful taxonomy and powerful new molecular methods now allow for the complete characterization of Pseudo-nitzschia populations and how they respond to environmental changes. Here we summarize research that represents our increased knowledge over the last decade of Pseudo-nitzschia and its production of DA, including changes in worldwide range, phylogeny, physiology, ecology, monitoring and public health impacts

    Diel vertical distribution, and herbivory of copepods in the south-western part of the Black Sea

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    The abundance and population structure of copepods were studied in the southwestern part of the Black Sea in May 1994, April and September 1995, April, June and September 1996. Vertical distribution and diel vertical migration of copepods were studied in April and September 1995 and June 1996. In addition, the grazing rates of three size classes of copepods-300-500, 500-1000 and 1000-2000 mum-were estimated in September 1995. The total abundance of copepods was higher in June samples due to the large contribution of the warm water species, Paracalanus parvus. Vertical distribution appeared to be related to season, species, stages of species and the oxygen concentration in the water column. Female, copepodite V (CV) and copepodite IV (CIV) stages of Calanus euxinus and female Pseudocalanus elongatus showed strong diel vertical migration from the surface waters to the oxygen minimum zone (OMZ). Copepodite stage V of C. euxinus showed seasonal migration, and was observed in diapaused phase at the OMZ in June and in September samplings. The large (1000-2000 mum) and medium(500-1000 mum) fractions of copepods had maximum gut fluorescence at night. Total grazing represented 32% of daily total integrated primary production. Phytoplankton carbon ingested met all three fractions of the basic metabolic requirements of the copepod community in the Black Sea

    Population structure, vertical distribution and diel migration of Sagitta setosa (Chaetognatha) in the south-western part of the Black Sea

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    The population structure of Sagitta serosa from the south-western part of the Black Sea was examined between May 1994 and December 1996. In addition, the vertical distribution and diel vertical migration of S.setosa were studied for juveniles (less than or equal to 5 mm) and adults (>5 mm) in April 1995, September 1995 and June 1996. The population structure studies showed that a new generation was introduced in September. Breeding was most intensive from June to November, indicated by the frequency of small-sized individuals. Diel vertical migration from the depth of the oxygen minimum zone to the surface was observed for adult S.setosa but not for juveniles. Juveniles were generally distributed above the seasonal thermocline. It is evident that adults are able to tolerate a wide range of oxygen concentrations and temperature
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