|START||NEW VOL 20||SEARCH||STATISTICS||PAS - GDANSK DIVISION|
pp. 167-180, vol. 12, 2009
Sea Fisheries Institute, Gdynia, Poland
Key words: ebullition of methane from seabed; Baltic Sea; fish diel vertical migration
Abstract: Acoustic information, collected in the form of measurements of integrated echo energies related to time and 3D space has been applied at the Sea Fisheries Institute since 1981 to examine the rough statistical relationships between clupeoids distribution in the Baltic and the relevant environmental factors. In this paper it is shown that the data collected can be also applied for very detail observation of dynamic phenomena in marine ecosystem. Two differentiated case studies were selected to show new acoustic applications in specific areas of oceanographic research. In the first case spatial characteristics of fish diel vertical migration in the southern Baltic was surveyed and analysed for the period 1994-2007, against the environmental background. In the second case acoustic sounding was applied to quantify ebullition of methane from Baltic sediments. Both phenomena are strongly dependent on climatic variability. For both cases the final characteristics of the phenomenon was given in the form of video frames, expressing the processes in time. Unique method of echo-recording transformation into video frames was described and applied to analyse the process of ebullition of methane from the seabed.
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© Polish Acoustical Society - Gdansk Department, Polish Academy of Sciences. This work is licensed under the Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported. (CC BY-NC-SA 3.0)