Распространение копепод в Эгейском море в марте 2012 года

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

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

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

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

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

Observations on the Rim Current structure, CIW formation and transport in the western Black Sea

CTD and ADCP measurements together with a sequence of satellite images indicate pronounced current meandering and eddy activity in the western Black Sea during April 1993. The Rim Current is identified as a well-defined meandering jet stream confined over the steepest topographic slope and associated cyclonic-anticyclonic eddy pairs located on both its sides. It has a form of highly energetic and unstable flow system, which, as it propagates cyclonically along the periphery of the basin, is modified in character. It possesses a two-layer vertical structure with uniform upper layer speed in excess of 50 cm/s (maximum value similar to 100 cm/s), followed by a relatively sharp change across the pycnocline (between 100 and 200 m) and the uniform sub-pycnocline currents of 20 cm/s (maximum value similar to 40 cm/s) observed up to the depth of similar to 350 dbar, being the approximate limit of ADCP measurements. The cross-stream velocity structure exhibits a narrow core region (similar to 30 km), flanked by a narrow zone of anticyclonic shear on its coastal side and a broader region of cyclonic shear on its offshore side. The northwestern shelf circulation is generally decoupled from the influence of the basinwide circulation and is characterized by much weaker currents, less than 10 cm/s. The southward coastal flow associated with the Danube and Dinepr Rivers is weak during the measurement period and is restricted to a very narrow coastal zone

Circulation and hydrographic characteristics of the Black Sea during July 1992

Hydrographic measurements performed during July 1992 are used to infer sub-basin and mesoscale circulation and water mass characteristics of the Black Sea. A notable feature of the circulation is the convoluted cyclonic boundary current system with distinctly different T, S characteristics. The coastal side of the Rim Current is characterized by a series of mesoscale eddies. The interior has a weaker circulation and little marked structure within an elongated low pressure cell. The baroclinic geostrophic flow field is vertically coherent and possesses smaller amplitude meanders as compared with the previous September 1991 observation (Oguz et al.,1994). In the northwestern shelf region, the fresh water inflows from the Danube as well as Dniepr and Dniestr Rivers give rise to a strong coastal salinity front confined above the seasonal thermocline. Both the coastal current and the Rim Current exhibit strong onshore-offshore meanders, indicating significant interaction between the interior and northwestern shelf waters. The influence of the fresh water inflow can be traced up to the east of the Bosphorus exit region, similar to 32 degrees E. The anoxic interface, identified by the 16.2 sigma-t surface, is located at levels deeper than 150 m along the coast, but is elevated sharply across the Rim Current frontal zone to its shallowest position of about 100m within the interior cyclonic cell

On the ADCP-derived Rim Current structure, CIW formation and the role of mesoscale eddies on the CIW transport in the Black Sea: Results from April 1993 observations

The shipboard CTD and ADCP current measurements, performed during 2-15 April 1993, yield new information on the current and hydrographic structures of the continental shelf and slope of the western Black Sea. The region is shown to be populated by pronounced current meandering and eddy activity. The narrow Rim Current frontal zone of the width similar to 50 km has a uniform upper layer speed in excess of 50 cm/s, with maximum measured currents of similar to 100 cm/s over the steepest topographic slope. Following a relatively sharp decrease across the pycnocline, uniform currents of similar to 20 cm/s art observed up to the depth of similar to 300 dbar, being the approximate limit of the ADCP measurements. The cross-stream velocity structure exhibit a narrow core region (similar to 10-20 km) confined over the topographic slope, flanked by a narrow zone of anticyclonic shear and a broader region of cyclonic shear on its coastal and offshore sides, respectively. The anticyclonic shear is stronger, comparable with the Coriolis parameter, and extends to greater depths. Except in the localized regions of the onshelf meanders of the Rim Current, the northwestern shelf circulation is decoupled from the influence of the basin-wide circulation, and characterized by much weaker currents of similar to 10 cm/s. The southward coastal flow associated with Danube and Dinepr Rivers is considerably weak at this time of the year and is confined to a narrow zone of similar to 20-30 km along the coast. The CTD data suggest temperature-induced overturning prior to the measurements, and subsequent formation of the Cold Intermediate Water (CIW) within the Northwestern Shelf (NWS) and center of the cyclonic gyre occupying the interior of the western basin. The newly formed shelf CIW is transported in part by the coastal current system, and in part, it flows downslope along the shelf in response to mesoscale structure of the local circulation system and intrude subsequently into the residual cold intermediate layer preserved in the frontal zone from the early winter season. The data indicate that the CIW mass, injected into the Rim Current zone quasi-horizontally from the shelf and periphery of the cyclonic gyre of the interior region, is carried by the Rim Current system around the basin