Data on diatom algae and silicoflagellates were obtained for the first time from the lower part of the stratotype of the Liman Formation (Liman Mount area), which allowed dating of this part of the ...Liman Formation as far back as the end of the Middle–beginning of the Late Miocene (
Denticulopsis praedimorpha
Zone, 12.9–11.5 Ma and
Thalassiosira yabei
Zone, 11.5–10.0 Ma by diatoms) and revealed the marine genesis of host deposits. The upper part of the stratotype of the Liman Formation (Pyata Cape area) that hosts the continental deposits with an assemblage of freshwater diatoms, with a certain degree of confidence may be referred to the Late Miocene (?)–Eopleistocene (Calabrian Stage).
Excavation in Posidonia oceanica matte in the ancient harbor of Klazomenai/Liman Tepe, on the Aegean coast of Turkey, demonstrates the stratigraphic archaeological potential of underwater excavation. ...Among the finds is a fractured wooden anchor arm exposed in situ. The anchor arm dates to approximately 600 b.c. based on stratigraphically associated ceramics, a dating supported by radiocarbon. The arm was found embedded in this marine sediment, which preserved the arm in its set position within the ancient sea floor. This archaeological excavation through matte and silt harbor sediments overturns the misconception that stratigraphic excavation is impossible in a marine environment. The excavation further boosts optimism regarding the preservation of maritime heritage along the littoral of the eastern Aegean and the many other Mediterranean regions where Posidonia oceanica grows.
Changes in fish distribution and migration patterns have occurred in mid- and high-latitude oceans worldwide in response to global change. Since the 1980s, the sea surface temperature (SST) of the ...Sea of Japan has increased significantly. The mechanisms behind these changes in migratory fish assemblages are difficult to determine from general capture fishery databases. This study collected a long-term dataset of set-net catches reported from Toyama Bay in western Japan to analyse catch compositions. The results indicated that in the coastal zone at the front of the Tsushima warm current and Liman cold current, increased SSTs have caused fluctuations both in the presence of cold-water and warm-water fish and in the timing of fishing seasons. Additionally, the results based on multi-dimensional scaling and cluster analyses showed that the study period can be divided into 5 clusters: (1) 1963–1964, (2) 1966–1972, (3) 1973–1998, (4) 1999–2006, and (5) 2007–2013; the similarity value was 89%. The boundaries between these clusters were similar to the timing of changes in SST, Pacific decadal oscillation, and North Pacific gyre oscillation. A species composition change analysis of these clusters showed that clustering was associated with changes in the intensities of the Tsushima warm current and Liman cold current. A northward expansion of low-latitude fish species, especially small- and medium-sized fish, was observed in Toyama Bay, similar to the expansion of high-latitude fish species into polar regions. Based on the principles of risk management and these research results, the adaptation strategies recommended in this study were differentiated into two categories: proactive adaptation and planned adaptation. (1) Establishment of pre-disaster adaptation capability: Proactive adaptation emphasizes countering the uncertainty in marine fishery production and improving the resilience of local communities. (2) Establishment of resilience during and after climate disasters: Planned adaptation can be used to manage uncertainty in the seafood supply by implementing adjustments in production and marketing and also to mitigate the impact of climate variation on the marine fishery industry and local coastal communities.
Holocene delta formations are unique records of regional sea-climate interactions. The Kızılırmak Delta is the biggest and richest wetland ecosystem in the Black Sea region of Turkey. The Black Sea ...was uniquely affected by rising sea levels due to its disconnection from the world oceans during the last glacial period. To understand the palaeoenvironmental impact on the delta plain we analysed a 14.5-m-long sediment core using palaeoecological ostracod analyses accompanied by a palaeo-salinity reconstruction based on sieve pore analysis on the ostracod Cyprideis torosa. This study depicts the interplay of terrestrial and marine settings forming mesohaline, shallow lagoons and deltaic lakes since ca. 7.9 ka cal BP. Lagoons with α-mesohaline to polyhaline salinities and β-mesohaline to oligohaline lake environments were identified. Reconstructed palaeo-sea level estimations depict a remarkable environmental variability. The lagoon habitats at 7.9 to 7.0 and 5.3 to 4 ka cal BP were dominated by Cyprideis torosa. Marine influence led to ostracod associations with Loxoconcha spp. and Tyrrhenocythere amnicola especially between 7.9 and 7.0 ka cal BP. Riverine influence in the same period, but especially at about 7.7 ka cal BP, caused dominating Amnicythere spp. Cyprideis torosa and Candona neglecta that characterise short phases of a mesohaline deltaic lake environment at about 7.7 and 7.0 ka cal BP as well as after 4 ka cal BP. With a subsequent salinity decrease, C. neglecta and (later on) Pseudocandona marchica became dominant with an interruption by another short-term lagoonal phase that might be associated with a ‘megadrought’ between 3.7 and 3.0 ka cal BP.
•Development of the Kızılırmak Delta (Southern Black Sea) since 7.9 ka cal BP•Cyprideis torosa and limnic/marine ostracod species in brackish palaeo-habitats•Morphometric palaeo-salinity reconstruction based on C. torosa•Mid- to Late Holocene sea level reconstruction of the Black Sea•Late Chalcolithic and Iron Age population of İkiztepe during lagoonal phases
The north-western part of the Black Sea Ukrainian coast is characterized by the presence of 12 marine lagoons which do not presently have permanent natural connections with the sea. Because of ...regional climate change, these lagoons have experienced a significant deficit of annual freshwater balance during the last decades and, consequently, an increase in salinity and eutrophication of their waters. One way to stabilize the hydroecological regime of lagoons is to maintain their regular connection with the sea via artificial connecting channels. The deepest and most prolonged Tyligulskyi Liman lagoon is used as an example to determine the morphometric characteristics (width, depth) of the artificial connecting channel which ensures bidirectional water exchange of the lagoon with the sea, i. e. its partial flushing. A numerical hydrodynamic model is used to estimate how the morphometric characteristics of the connecting channel influence the intensity of water exchange between the lagoon and the sea and of water renewal by seawater for the various parts of the lagoon. The dynamics of sea water volume concentration in reference points in the lagoon is used as an indicator of seawater intrusion into the lagoon and their degree of water renewal in its various zones. The proposed methodology could be used for other lagoons of the same type in the north-western part of the Black Sea.
A retrospective analysis of changes in land uses within the bottoms of closed mesodepressions in Azov district of Rostov oblast for the period from 1968 to 2014 was performed. A cartographic analysis ...of changes in the degree of waterlogging of these depressions and the related changes in the character of land use was based on remote sensing data. This study was performed within the framework of a general problem-oriented system of the retrospective monitoring of the soil and land cover. It was found that the waterlogged area in the mesodepressions in the particular years does not depend on the anthropogenic loads and is subjected to cyclic variations. Temporal intervals for the wetting–drying cycles were determined. The maximum drying of the bottoms of mesodepressions was observed in 1975, 1990, and 2011.
The paper outlines the mathematical structure of the numerical mathematical model of water eutrophication. The model is based on the numerical non-stationary hydrothermodynamic model MECCA (Model for ...Estuarine and Coastal Circulation Assessment) supplemented with a chemical-biological modular unit designed in accordance with the principles of preparation of the water quality model RCA-HydroQual with some modifications introduced by the author. The chemical-biological unit of the model includes a description of the dynamics of the following hydroecological variables at a local point of space: biomass of phytoplankton, mineralization-resistant organic phosphorus in suspended (detrital) and dissolved fractions, labile organic phosphorus in suspended and dissolved fractions, dissolved mineral phosphorus, stable organic nitrogen in suspended and dissolved fractions, labile organic nitrogen in suspended and dissolved fractions, ammonium and nitrate nitrogen, suspended and dissolved fractions of organic carbon resistant to biochemical oxidation, suspended and dissolved fractions of labile organic carbon and water-dissolved oxygen. The paper presents results of calibration and verification of 1D version of the model for the case of the Tyligulskiy Liman (Estuary) in the northwestern part of the Black Sea. A conclusion is drawn that the model makes it possible to display the main features of the annual dynamics of hydroecological characteristics of the liman during phytoplankton vegetation season, in particular, the conditions determining the processes of primary production and biochemical oxidation of organic substance, regeneration of mineral forms of biogenic elements. Application of the model in order to assess the impact of deepening the ‘liman-sea’ connecting canal on the hydroecological characteristics of the Tyligulskiy Liman proved that intensification of water exchange with the sea through the canal will help to reduce phytoplankton production, concentration of organic substance in the water of the liman and, ultimately, will lead to improvement of its trophic status. The model is expected to be further used to assess the effectiveness of various scenarios of managing the hydroecological regime of the limans of the north-western Black Sea region considering the changes of climatic conditions.
The potentialities of averting a further salinization of the Tyligulskyi Liman lagoon were identified on the basis of the results of the hydrodynamic modelling, using the numerical model ...Delft3D-FLOW. The means to prevent the salinization in the lagoon include a reconstruction of the “lagoon-sea” interconnecting channel and the changing of its operational schedule, as well as the increasing of the river inflow considering the climatic conditions of the first half of the XXI century. The results of the verification of the hydrodynamic model are given. It is shown that for stabilizing water levels and reducing the rate of the water salinity in the lagoon the most effective option is the year-round operation of the deepened “lagoon-sea” connecting channel. This will be facilitated by a multi-directional exchange of water through the channel caused by wind-induced water level oscillations in the lagoon and in the sea. However, while maintaining the current level of the water management activity in the catchment area of the lagoon, a long-term trend of increasing water salinity in the lagoon still remains. Only the restoration of natural river discharge into the lagoon could reduce the tendency of growing water salinity to a minimum.
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