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1

Impact of salinity on the underwater noise generated by small scale air entrainment events

Szuszkiewicz J., Klusek Z., Gorska N.

Hydroacoustics

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2017

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Vol. 20

167--172

EN

Some part of the energy released in the wave breaking process is transformed into the energy of the noise. This sound depends on the water properties, however, there is a lack of reliable data concerning the underwater noise generated by less energetic events. The aim of this study was to understand the impact of salinity on the underwater noise produced during small scale air entrainment events, typical for low wind speed conditions. The tipping trough experiment was performed in a small tank to generate the small scale air injections. Four, linearly placed hydrophones HTI-96-MIN were used to record the acoustic noise accompanying this phenomenon. The bubble plume development, and underwater noise spectra, were compared for salty and fresh water. The potential energy of the modeled events resulted in different spectra, and salinity played an essential role in the emitted underwater noise.

2

An acoustic study of zooplankton diel vertical migration in the Black Sea

Pezacki P. D., Gorska N., Soloviev V.

Hydroacoustics

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2017

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Vol. 20

139--148

EN

Reliable, rapid and non-invasive techniques are important for the monitoring of the ecosystem of the semi-enclosed Black Sea, especially sensitive to the human impact. Hydroacoustic techniques meet these requirements. In the study, the ADCP data (volume backscattering strength and water velocities), collected in the north-east part of the Black Sea in October 2014, were used to understand some biotic and abiotic processes in the environment. The study was motivated by the fact that the used ADCP mounted on the autonomous (moving vertically) platform provided measurements with significantly higher spatial resolution that it was in the previous hydroacoustical studies of Black Sea ecosystem. The main objective of the analysis was to determine the velocity of zooplankton diel vertical migration and understand the processes responsible for the variability of the volume backscattering strength.

3

Modelling of acoustic backscattering by southern Baltic herring

Idczak J., Gorska N.

Hydroacoustics

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2016

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Vol. 19

145--152

EN

Assessment of Baltic herring abundance can be carried out using acoustic techniques. Analysis of the relationship between the Baltic herring individual target strength, TS, and the total fish length, L, important for the acoustic assessment, showed the relationship to be dependent on the location of the study area. This finding motivated a detailed analysis of the relationship for the herring occurring in the southern Baltic ICES subdivisions 24, 25, and 26, in which Poland is responsible for the acoustic herring abundance assessment. The paper addresses the numerical analysis of the backscattering properties of the southern Baltic herring. The modelling approach used to study the backscattering was based on the Modal Series-Based Deformed Cylinder Model approximation. Details of the individual herring swimbladders were taken into account. Morphometric data necessary for the analysis was obtained from X-ray images of herring from the Polish coastal zone (ICES subdivision 26).

4

Influence of microphytobenthos photosynthesis on the spectral characteristics of the signal reflected from Baltic sandy sediments

Jaśniewicz D., Gorska N.

Hydroacoustics

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2016

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Vol. 19

165--171

EN

The use of hydracoustical techniques to classify benthic fauna and flora is one of the important challenges in present marine research. It is crucial to understand the microphytobenthos photosynthesis impact on the backscattering properties of the sea floor in the Baltic Sea, where the techniques are actively developed now. This motivated our study. The data used in the analysis was collected in the multiday laboratory experiment conducted in the frame of the grant of the National Science Centre, Poland (No. N306 773940). In this experiment, during changing light conditions (light/dark photocycles), the hydroacoustical backscattering data was acquired in the aquarium with a sandy bottom. The constant temperature and salinity conditions, typical for the Southern Baltic, were kept, and oxygen content was monitored. In this paper data collected at 280 kHz, was processed. It was studied how the energy of echo and power spectral density of the echo signal, are sensitive to the microphytobenthos photosynthesis.

5

Realizacja projektu naukowego w zakresie podmorskiej sekwestracji CO₂ w południowej części Morza Bałtyckiego

Zajfert G., Tęgowski J., Sokołowski A., Latała A., Gorska N.

Bezpieczeństwo Pracy i Ochrona Środowiska w Górnictwie

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2015

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nr 11

3--8

PL

Wzrost emisji gazów cieplarnianych do atmosfery staje się ważnym problemem wielu krajów na świecie. Jednym ze sposobów ograniczenia ich emisji jest geologiczna sekwestracja CO₂ pochodzenia antropogenicznego. W celu poznania możliwości stosowania tego rozwiązania na skalę przemysłową prowadzi się projekty naukowe i działania demonstracyjne. W artykule opisano realizację projektu badawczego, dotyczącego sekwestracji CO₂ w strukturach podmorskich w Polskiej Wyłącznej Strefie Ekonomicznej Morza Bałtyckiego. W efekcie realizacji projektu powstała szeroka baza danych i informacji o charakterze interdyscyplinarnym. Na podstawie ich analizy przedstawiono wstępne wnioski dla potencjalnej lokalizacji podmorskiego zatłaczania dwutlenku węgla. Ponadto projekt dostarczył cennych doświadczeń, które mogą posłużyć jako wytyczne do postępowania przy realizacji sekwestracji na skalę przemysłową.

EN

Global climate changes, which are mainly related to human activity, including emission of anthropogenic CO₂, resulted in significant intensification of research activities which focus on development of the technologies enable to reduce anthropogenic emissions. Carbon Capture and Storage (CCS) is regarded as a key technology for the reduction of CO₂ emissions from industrial sources an international level. This paper presents the first research study on potential CCS implementation in the Polish Exclusive Economic Zone of the Baltic Sea. The main place of interest is the undersea geological structure of B3 oil field. Currently, oil field is operated by LOTOS Petrobaltic company. For the purposes of the project the structure has been identified and characterized, basing on archival data and research in 2012.It has been shown, that the anticlinal form of reservoir is closed form and has the potential trapping properties, further more confirmed the tightness of overburden. It has been identified close situated fault, which could be a potential place for leakage and migration of CO2.The fault is inactive, without signs of hydrocarbon migration. Geochemical research of bottom sediments and waters near bottom indicate the conditions typical for the southern part of the Baltic Sea, low salinity and oxygen content, low concentration of hydrogen sulphide and methane. The seabed there is inhabited by very few organisms resistant to adverse factors of the habitat in the study area. The potential biological consequences of a gas leakage can be assessed as limited.

6

Impact of Microphytobenthos Photosynthesis on the Characteristics of the Echo Signal from Baltic Sandy Sediments

Gorska N., Kowalska-Duda E., Marszal J., Schmidt J., Klusek Z.

Archives of Acoustics

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2015

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Vol. 40, No. 3

395--405

EN

The understanding the influence of biological processes on the characteristics of the signals backscattered by the sea floor is crucial in the development of the hydroacoustical benthic habitat classification techniques. The impact of the microphytobenthos photosynthesis on the acoustical backscattering properties of the Atlantic sandy sediments was previously demonstrated by Holliday et al. (2004) and Wildman and Huettel (2012). To account for the sensitivity of the hydroacoustical classification techniques to the backscattering properties of local marine sediments, it is important to understand the microphytobenthos photosynthesis impact for the Baltic Sea where the techniques are being actively developed now. This is the main motivation of the paper. In the paper the influence of the microphytobenthos photosynthesis on the characteristics of the echo signals reflected by sandy sediments in the typical Baltic temperature and the salinity conditions is discussed. The interdisciplinary multiday laboratory experiment was conducted to study the impact of benthic microalgal photosynthesis on the characteristics of the echo signal reflected by sandy sediments. Hydroacoustical data were collected under controlled constant light, temperature and salinity conditions. The oxygen content at different levels of the water column was simultaneously monitored.

7

Acoustic backscattering characteristics of mytilus dulis trossulus (southern Baltic Sea)

Gorska N., Kowalska E.

Hydroacoustics

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2012

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Vol. 15

49-56

EN

Study of benthic habitats is significant from ecological and economical point of view. Non–invasive, rapid and relatively cheap methods of the habitat classification are required. It is the reason why the hydroacoustic classification techniques are developed. These techniques are sensitive to the seabed sediments type and the backscattering properties of the benthic habitats, and are developed for individual marine conditions. Last few years the hydroacoustic classification algorithms are developed for the Southern Baltic Sea. To improve the algorithms it is required to know the backscattering properties of the typical benthic individual and aggregated organisms. The main objective of the article is the study of the backscattering characteristics of benthic shelled animals Mytilus edulis trossulus, which is one of the dominant species in the southern Baltic Sea. The approach is based on the numerical modelling of the acoustic wave backscattering by the individual organisms and their aggregations and comparison of the modelling results with the measured backscattered data.

8

Study of swimbladder morphometry of baltic herring and sprat (development of measurement methodology)

Idczak J., Gorska N., Arciszewski B.

Hydroacoustics

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2011

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Vol. 14

61-68

EN

Effective management of Baltic clupeids, which are valuable commercially and ecologically, requires the biomass control. The acoustical techniques are recognized as effective in fish stock assessment. The study of Baltic herring and sprat individual backscattering characteristics is required for the accurate biomass estimation using acoustical techniques. The previous measurements demonstrated significant dependence of the backscattering properties of Baltic clupeids on their geographical location. For southern Baltic Sea the properties are not recognized sufficiently yet. Accounting for that fish swimbladder morphometry effectively impacts on the backscattering, it is important to study the morphometry of southern Baltic herring and sprat. It motivated the paper study. The paper is addressed to the development of the methodology of the analysis of the accurate shape of the swimbladder. The way of the fish catch, transport and storage, the X-ray irradiation and the X-ray image analysis was developed.

9

On the acoustic backscattering by Baltic herring and sprat

Gorska N., Idczak J.

Hydroacoustics

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2010

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Vol. 13

89-100

EN

Accurate abundance estimate of Baltic clupeids, herring and sprat, is required for their sustainable exploitation. The understanding the sound backscattering of individual fish is important for employing the acoustical techniques, which are widely used in the estimation. The previous studies demonstrated that the improvement of the understanding is critical for the Baltic herring and sprat. It was the main motivation of the paper. The main objective was understanding the difference in acoustic backscattering by herring and sprat in the Baltic Sea. The study was based on a numerical modeling of backscattering by the individual fish. The model input data (morphometric parameters of fish) are obtained using available X-ray images of Baltic sprat and herring. The difference in the backscattered energy, backscattering directivity pattern, and the body contribution into the backscattering of the total fish was demonstrated for the considered species.

10

Acoustical techniques of underwater meadow monitoring in the Puck Buy (Southern Baltic Sea)

Klusek Z., Gorska N., Tęgowski J., Groza K., Faghani D., Gajewski L., Nowak J., Kruk-Dowgiałło L., Opioła R.

Hydroacoustics

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2003

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Vol. 6

79--90

EN

The main motivation of this paper was to develop acoustical techniques to monitor underwater meadows. The data, collected with down-looking echo sounder, were used to develop method of bottom detection and tracking and measurement of vegetation canopy height in the Puck Bay. This method and its accuracy are discussed in details. The other possibilities of recognition between covered and uncovered bottom were also reviewed. The effectiveness of using side scan sonar in study vegetation spatial distribution is demonstrated.

11

On sound extinction by biological targets

Gorska N., Chu D.

Hydroacoustics

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2001

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Vol. 4

69--80

EN

To address the importance of sound extinction by densely aggregated biological entities, a systematic theoretical study of this problem is presented. The physical insight into the extinction phenomenon is given. The agreement between theoretical and experimental results is discussed.

12

On sound extinction by zooplankton

Gorska N.

Hydroacoustics

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1999

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Vol. 2

45--50

EN

Theoretical investigation of sound extinction cross section of zooplankton individual is made on the basis of optical theorem. To find general properties of this characteristic, analytical model, describing the scattering at krill individual. is used. The extinction cross section is evaluated for various krill species. The dependence of the extinction cross section on the sound frequency is obtained. The paper presents the influence of the acoustical properties of the biological tissue and geometrical form of individual on the extinction cross section. The role of sound absorption in krill tissue is discussed.