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1

Distribution and role of the genus Oithona (Copepoda: Cyclopoida) in the South China Sea

Wang L., Du F., Wang X., Li Y., Ning J.

Oceanologia

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2017

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No. 59 (3)

300--310

EN

The relationships between the small cyclopoid copepod Oithona and hydrological factors, phytoplankton and ichthyoplankton were evaluated using the data obtained in the central South China Sea (SCS) in summer 2014. The genus abundance ranged from 6.00 ind. m−3 to 93.75 ind. m−3 with high abundance band occurring in the branch of SCS Monsoon Jet. The lower temperature and higher salinity in the surface water of the band than other zones indicated that deep water intrusion was a positive factor for aggregation of the genus. The community structure of the genus was dominated by Oithona plumifera and Oithona similis made up 97% of the genus abundance associated with Oithona tenuis. The result of db-RDA analysis showed that the community structure of the genus was affected by temperature, Chl a, larval fishes and fish spawns, and temperature was the most important limiting factor. The result of GAMs analysis showed that abundance of O. tenuis, and copepodites were affected by Chl a, larval fishes and fish spawns; abundance of O. similis was affected by Chl a and fish spawns; and abundance of O. plumifera was affected by Chl a and larval fishes. Therefore, we suggest that the branch of SCS Monsoon Jet and deep water intrusion favor aggregation of plankton in the central SCS in summer. We confirm that the temperature is the limiting factor to the reproduction of the genus Oithona in tropic seas and the genus Oithona is a food-web linker between primary production and larval fishes in the central SCS.

2

Hydrophysical parameters of seawater in front of Ustka during the summer season 2013

Kałas M., Misiewicz E.

Biuletyn Instytutu Morskiego w Gdańsku

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2017

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Vol. 32, No. 1

37--45

EN

The article presents spatial distribution of hydrophysical parameters of coastal waters near Ustka, stretching towards the eastern part of Słupsk Bank which appeared there in July 2013. It covers studies of distribution of temperature, salinity and seawater density across the entire cross-section of the water depth. Additionally, directional distributions of the water flows recorded at Baltic Sea, as well as information on local wind speed and direction derived from numerical model of the atmosphere are presented. The resulting image of water density distribution across the entire cross-section of the water depth under steady conditions of stratification allowed determination of character and extent of river water distribution seawards of the Słupia River mouth during summer 2013

PL

W pracy przedstawiono rozkład przestrzenny parametrów hydrofizycznych wody na przybrzeżnych akwenach przedpola Ustki do północnych zboczy wschodniej części Ławicy Słupskiej zarejestrowany w lipcu 2013 roku. W tym celu zbadano rozkłady temperatury, zasolenia oraz gęstości wody morskiej w całym przekroju toni wzdłuż przekroju Ustka - północny stok Ławicy Słupskiej. Dodatkowo przedstawiono rozkłady kierunkowe przepływów wody zarejestrowane w tym czasie na morzu, oraz informacje o kierunkach i prędkościach wiatru lokalnego z prognoz numerycznego modelu atmosfery. Uzyskany obraz rozkładu gęstości wody w całym przekroju toni w warunkach ustalonej stratyfikacji pozwolił na przedstawienie charakteru i zasięgu rozpływu wód rzecznych na przedpolu ujścia Słupi w okresie letnim 2013 roku

3

Sediment transport beyond the surf zone under waves and currents of the non-tidal sea: Lubiatowo (Poland) case study

Ostrowski R., Stella M.

Archives of Hydro-Engineering and Environmental Mechanics

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2016

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Vol. 63, nr 1

63--77

EN

The paper deals with the sandy coastal zone at Lubiatowo in Poland (the south Baltic Sea). The study comprises experimental and theoretical investigations of hydrodynamic and lithodynamic processes in the coastal region located close to the seaward boundary of the surf zone and beyond the surf zone. The analysis is based on field data collected at the IBW PAN Coastal Research Station in Lubiatowo. The data consist of wind velocity reconstructed from the long-term wave climate, deep-water wave buoy records and sea bottom soil parameters. Nearbed flow velocities induced by waves and currents, as well as bed shear stresses are theoretically modelled for various conditions to determine sediment motion regimes in the considered area. The paper discusses the possibility of occasional intensive sediment transport and the occurrence of distinct sea bed changes at bigger water depths.

4

Energy retrieval from sea currents and tides

Szelangiewicz T., Żelazny K.

Zeszyty Naukowe Akademii Morskiej w Szczecinie

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2015

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nr 41 (113)

24--29

EN

Seas and oceans show variations in water levels caused by tides and continuous flow of water in the form of sea and ocean currents. Tides are most visible close to the coastline – tide parameters (water speed or change in sea level) allow construction of installations producing electric energy. Sea currents – superficial and deep are characterized by means of constant speeds and directions. Therefore energy retrieval from these elements of sea environment looks very promising. The article presents basic information on tides and currents useful for designing hydroelectric power plants. The already constructed hydroelectric power stations are also presented here together with several design solutions of future such installations.

5

Modelling of the silting up of navigation channels

Kaczmarek L. M.

Technical Sciences / University of Warmia and Mazury in Olsztyn

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2008

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nr 11

175-187

EN

A mathematical model describing transport of non-uniformly graded sediments has been applied to analyzing the silting up of approach routes (navigation channels) leading to ports. This model distinguishes three layers in the movement of sediments, assuming that the vertical sorting occurs only in the process of picking up grains in the contact layer. It is also assumed that along the widnward edge of the route sediments are transported in the bedload and contact layers during the wave crest phase and - as suspended sediments - in the outer region under the influence of the resultant current. On the leeward side sediments are transported only during the wave trough phase in the bedload and contact layer. The computations have demonstrated that the above model can be a useful tool for predicting both the rate and volume of sediments silting up navigation channels as well as grain-size distribution of sediments which fill up a water route.

PL

Model matematyczny transportu osadów niejednorodnych granulometrycznie zastosowano do analizy zapiaszczania torów podejściowych (kanałów nawigacyjnych) do portów. Wyszczególnia on trzy warstwy ruchu osadów, przy czym założono, że pionowe sortowanie odbywa się tylko w procesie podrywania ziaren w warstwie kontaktowej. Zakłada się, że na krawędzi nawietrznej toru osady transportowane są w fazie grzbietu fali w warstwie wleczenia i kontaktowej oraz zewnętrznej - w formie zawieszonej - pod wpływem wypadkowego prądu. Na krawędzi zawietrznej osady transportowane są tylko w fazie doliny fali w warstwie wleczenia i kontaktowej. Przeprowadzone obliczenia pokazują, że zastosowany model może być użytecznym narzędziem w predykcji zarówno wielkości i tempa zapiaszczania, jak i określaniu rozkładów granulometrycznych osadów wypełniających tor wodny.