MACROBENTHIC NEMATODES INHABITING MUSSEL BEDS: SEASONAL VARIABILITY IN THE POPULATION STRUCTURE OF ENOPLUS QUADRIDENTATUS BERLIN, 1853 AROUND SINOP PENINSULA (SOUTHERN BLACK SEA)

Purpose. The study is aimed at investigating seasonal variability and vertical distribution of the sub-mesoscale currents energy (scales L = 1 … 10 km, T = 1 … 10 days) in the deep and shelf zones of the Black Sea. Methods and Results. The study is based on the spectral analysis of the results obtained from the NEMO model numerical calculations performed with high spatial resolution 1 km. The analysis shows that the seasonal variability of the submesoscale energy is significantly different in deep and shelf zones of the basin. At the same time, in both regions, seasonal variation of energy of the sub-mesoscale currents with scales L < 10 rm (Esp) is in good agreement with that of the density fluctuations on the same scales. In the central part of the sea, the high values of Esp are concentrated in the upper mixed layer throughout the whole year. The Esp peak is observed in winter at the depths 0–40 m, which indicates the important role of baroclinic instability induced by the inhomogeneous distribution of the mixed layer depth (MLD) in the generation of sub-mesoscale processes. At the same time, in February in the central part of the northwestern shelf, an absolute minimum of (Esp) is observed. This minimum is caused by the complete mixing and barotropization of the water column. The Esp maximum values are observed in the shelf in September – October. This is related to the intensification of the brackish water transport from the river mouths by mesoscale eddies. In the autumn period high values of Esp in the shelf and deep part of the basin are observed in the deeper layer, compare to summer months .Variability of the Esp vertical distribution coincides to the time variation of MLD. Variability of the submesoscale energy is of a pulsating character with the short-term intensifications and weakenings. Such variability is significantly related to the passing of the mesoscale fronts and the cross-shelf water transport caused by the eddies and upwellings, which lead to the increase of the baroclinic instability. Conclusions. Analysis of the seasonal and vertical variability of the submesoscale currents in the Black Sea deep and shelf zones evidences about the decisive role of the baroclinic instability triggered mainly by the heterogeneity of MLD on their dynamics.

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Influence of Seasonal Variability of the Wind Stress Vorticity on the Structure of the Black Sea Circulation

Morskoy gidrofizicheskiy zhurnal ◽

10.22449/0233-7584-2018-5-373-388 ◽

2018 ◽

Vol 34 (5) ◽

Author(s):

Pavlushin A. А. ◽

N. B. Shapiro ◽

E. N. Mikhailova ◽

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...

Keyword(s):

Black Sea ◽

Wind Stress ◽

Seasonal Variability ◽

The Black Sea

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The polyclad fauna (Platyhelminthes, Rhabditophora) of the Sinop Peninsula (Black Sea, Turkey) with the description of a new species of Cryptocelis Lang, 1884

Mediterranean Marine Science ◽

10.12681/mms.24666 ◽

2021 ◽

Vol 22 (1) ◽

pp. 141

Author(s):

MEHREZ GAMMOUDI ◽

VERONICA N. BULNES ◽

GÜLEY KURT

Keyword(s):

New Species ◽

Black Sea ◽

New Records ◽

Reproductive Behaviour ◽

Short Description ◽

The Black Sea ◽

Systematic Sampling ◽

Dorsal Wall ◽

Mussel Beds ◽

A New Species

Between October 2013 and July 2014, 40 polyclad specimens were collected during the systematic sampling of mussel beds along the coast of the Sinop Peninsula (Western Black Sea). Six species were identified, including a new Cryptocelis species. Cryptocelis sinopae sp. nov. is characterized by possessing a prostatic vesicle lined with a ridged fold in its anterior end and the presence of two secretory glandular folds in the distal dorsal wall of male atrium. Additionally, new records of Echinoplana celerrima Haswell, 1907 and Leptoplana mediterranea (Bock, 1913) are reported for the Black Sea and Turkey; and Leptoplana tremellaris (Müller OF, 1774) and Prosthiostomum siphunculus Delle Chiaje, 1822 for the coast of the Black Sea of Turkey. A short description of the reproductive behaviour of Pleioplana okusi Bulnes, Kalkan and Karahan, 2009 and Cryptocelis sinopae sp. nov. will be also provided.

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The role of the isolation of the marginal seas during the Pleistocene in the genetic structure of black sea bream Acanthopagrus schlegelii (Bleeker, 1854) in the coastal waters of Japan

PeerJ ◽

10.7717/peerj.11001 ◽

2021 ◽

Vol 9 ◽

pp. e11001

Author(s):

Yutaro Yamashita ◽

Gustavo Sanchez ◽

Kentaro Kawai ◽

Satoshi Tomano ◽

Hiroki Fujita ◽

...

Keyword(s):

Population Structure ◽

Pacific Ocean ◽

Black Sea ◽

Coastal Waters ◽

Sea Bream ◽

The Black Sea ◽

Northwestern Pacific ◽

Marginal Seas ◽

Coastal Marine ◽

Japanese Waters

The black sea bream Acanthopagrus schlegelii (Bleeker, 1854) is a commercially important species in Japanese waters. Assessing its population structure is essential to ensure its sustainability. In the Northwestern Pacific, historical glacial and interglacial periods during the Pleistocene have shaped the population structure of many coastal marine fishes. However, whether these events affected the population of black sea bream remains unknown. To test this hypothesis and to assess the population structure of black sea bream, we used 1,046 sequences of the mitochondrial control region from individuals collected throughout almost the entire Japanese coastal waters and combined them with 118 sequences from populations distributed in other marginal seas of the Northwestern Pacific Ocean. As in other coastal marine fish with similar distribution, we also found evidence that the glacial refugia on the marginal seas prompted the formation of three lineages in black sea bream. These lineages present signatures of population growth that coincided with the interglacial periods of the Pleistocene. While the origin of Lineages B and C remains unclear, the higher relative frequency of Lineage A in the southernmost location suggests its origin in the South China Sea. The non-significant pairwise ΦST and AMOVA of Japanese populations and the presence of these three lineages mixed in Japanese waters; strongly suggest that these lineages are homogenized in both the Sea of Japan and the Pacific Ocean. Our results indicate that the black sea bream should be managed as a single stock in Japan until the strength of connectivity in contemporary populations is further addressed using non-coding nuclear markers.

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