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Oceanologia, Volume 56, pp 651-660; https://doi.org/10.5697/oc.55-3.651
Oceanologia, Volume 56, pp 445-460; https://doi.org/10.5697/oc.56-3.445
Oceanologia, Volume 56, pp 461-475; https://doi.org/10.5697/oc.56-3.461
The results of a field study of surface film spreading on the sea surface are presented. The experiments were carried out in the coastal zone of the Black Sea in a wide range of wind speeds and wave conditions. Vegetable oil was used for preparing the surfactants. It was found that at moderate and strong wind speeds the slicks take on a shape similar to an ellipse and are orientated in the direction of the air flow. An increase in the speed of the spreading slick along its major axis with strong wind was discovered
Allelopathic interactions between the red-tide causative dinoflagellate Prorocentrum donghaiense and the diatom Phaeodactylum tricornutum**This study was supported by the Natural Science Foundation of China-Guangdong Province Joint Key Project (U1133003) Science Technology Planning Project of Guangdong Province (2012B020307009) Open Fund from Key Laboratory of Aquatic Eutrophication Control of Harmful Algal Blooms of Guangdong Higher Education Institutes Open Fund from Key Laboratory of Microbial Resources Collection Preservation Ministry of Agriculture.
Oceanologia, Volume 56, pp 639-650; https://doi.org/10.5697/oc.56-3.639
Between the red-tide causative dinoflagellate Prorocentrum donghaiense and the diatom Phaeodactylum tricornutum* doi:10.5697/oc.56-3.639 OCEANOLOGIA, 56 (3), 2014. pp. 639–650. ©C Copyright b
DOC and POC in the water column of the southern Baltic. Part I. Evaluation of factors influencing sources, distribution and concentration dynamics of organic matter**This study was supported by the Baltic-C/BONUS Plus EUFP6 Project, statutory activities of Institute of Oceanology PAN, Sopot and the Polish Ministry of Science and Higher Education, grant No. N N306 404338.
Oceanologia, Volume 56, pp 523-548; https://doi.org/10.5697/oc.55-3.523
Organic substances are important components of the marine environment as they determine the properties of seawater and the key biogeochemical processes taking place in it. Organic carbon (OC) is a measure of organic matter. For practical purposes, OC is divided into dissolved organic carbon (DOC) and particulate organic carbon (POC). Both DOC and POC play a major role in the carbon cycle, especially in shelf seas like the Baltic, where their concentrations are substantial. In a three-year study (2009–2011) seawater samples for DOC and POC measurements were collected from stations located in the Gdańsk Deep, the Gotland Deep and the Bornholm Deep. The accuracy and precision of analysis were satisfactory; the recovery was better than 95%, and the relative standard deviation was 4% (n =5). Concentrations of chlorophyll a, phaeopigment a, salinity, pH and temperature were also measured in the same samples. These parameters were selected as proxies of processes contributing to DOC and POC abundance.The aim of the study was to address questions regarding the vertical, horizontal and seasonal dynamics of both DOC and POC in the Baltic Sea and the factors influencing carbon concentrations. In general, the highest concentrations of both DOC and POC were recorded in the surface water layer (DOC~4.7mgdm−3, POC~0.6mgdm−3) as a consequence of intensive phytoplankton activity, and in the halocline layer (DOC~5.1mgdm−3, POC~0.4mgdm−3). The lowest DOC and POC concentrations were measured in the sub-halocline water layer, where the values did not exceed 3.5mgdm−3 (DOC) and 0.1mgdm−3 (POC). Seasonally, the highest DOC and POC concentrations were measured during the growing season: surface DOC~5.0mgdm−3; sub-halocline DOC~4.1mgdm−3 and surface POC~∼0.9mgdm−3, sub-halocline POC~∼0.2mgdm−3. The ANOVA Kruskal-Wallis test results indicate statistically significant differences among the three study sites regarding average concentrations, and concentrations in particular water layers and seasons. It shows that concentrations of DOC and POC differ in sub-basins of the Baltic Sea. The differences were attributed to the varying distances from river mouths to study sites or the different starting times and/or durations of the spring algal blooms. Statistically significant dependences were found between both DOC and POC concentrations and Chl a (phytoplankton biomass), pH (phytoplankton photosynthetic rate), pheo (zooplankton sloppy feeding), salinity (river run-off and North Sea water inflows) and water temperature (season). This was taken as proof that these factors influence DOC and POC in the study areas
Oceanologia, Volume 56, pp 549-564; https://doi.org/10.5697/oc.55-3.549
We performed genetic analyses of three Baltic eelgrass (Zostera marina) populations in Puck Bay (PB), Cudema Bay (CB) and Greifswalder Bodden (GB). The aim of this study was to identify the eelgrass population genetically closest to that from the PB, which could potentially serve as a reservoir for the restoration of the underwater meadows in this bay, seriously degraded in the past. We applied a 12-microsatellite assay to test the genetic distance between the target eelgrass populations. We found that the allelic richness values of the GB, PB and CB populations were 2.25, 3.77 and 3.50 respectively. The genetic diversity found in GB was low and could be explained by the population’s history, whereas the diversity of CB was higher than expected in a population located at the edge of the species’ range. Analyses of genetic differentiation and structure showed that of the three populations studied, PB and CB were closer to each other than to the GB population. The reasons for this differentiation in eelgrass populations and the implications of the results of their genetic analysis on the planned restoration of the PB populations are discussed
Oceanologia, Volume 56, pp 565-581; https://doi.org/10.5697/oc.55-3.565
Short-term variation in zooplankton community from Daya Bay with outbreaks of Penilia avirostris**This research was supported by the Knowledge Innovation Program of the Chinese Academy of Sciences (SQ201307), the Public Science and Technology Research Funds Projects of Ocean (No. 201305030) and the National Natural Science Foundation of China (No. 41276159, 31101619, 41130855 and 41276161).
Oceanologia, Volume 56, pp 583-602; https://doi.org/10.5697/oc.55-3.583
Benthic non-indigenous species among indigenous species and their habitat preferences in Puck Bay (southern Baltic Sea)**This work was carried out under the ‘Ecosystem Approach to Marine Spatial Planning – Polish Marine Areas and the Natura 2000 Network’ project founded by an EEA grant from Iceland, Lichtenstein and Norway and partly by research grant BW/G 220-5-0232-9.
Oceanologia, Volume 56, pp 603-628; https://doi.org/10.5697/oc.55-3.603
To date 11 non-indigenous benthic taxa have been reported in Puck Bay (southern Baltic Sea). Five of the 34 taxa forming the soft bottom communities are regarded as non-indigenous to this area. They are Marenzelleria spp., Mya arenaria, Potamopyrgus antipodarum, Gammarus tigrinus and Amphibalanus improvisus. Non-indigenous species comprised up to 33% of the total number of identified macrofaunal taxa (mean 17%). The average proportion of aliens was 6% (max 46%) in the total abundance of macrofauna, and 10% (max 65%) in the biomass. A significant positive relationship was found between the numbers of native and non-indigenous taxa. The number of native taxa was significantly higher on a sea bed covered with vascular plants than on an unvegetated one, but no such relationship was found for their abundance. No significant differences were found in the number and abundance of non-indigenous species between sea beds devoid of vegetation and those covered with vascular plants, Chara spp. or mats of filamentous algae. G. tigrinus preferred a sea bed with vegetation, whereas Marenzelleria spp. decidedly preferred one without vegetation
Oceanologia, Volume 56, pp 629-638; https://doi.org/10.5697/oc.55-3.629
Oceanologia, Volume 56, pp 477-496; https://doi.org/10.5697/oc.55-3.477
Water flow through the beach body plays an important role in the biological status of the organisms inhabiting the beach sand. For tideless seas, the groundwater flow in shallow water is governed entirely by the surface wave dynamics on the beach. As waves propagate towards the shore, they become steeper owing to the decreasing water depth and at some depth, the waves lose their stability and start to break. When waves break, their energy is dissipated and the spatial changes of the radiation stress give rise to changes in the mean sea level, known as the set-up. The mean shore pressure gradient due to the wave set-up drives the groundwater circulation within the beach zone. This paper discusses the circulation of groundwater resulting from a nonlinear set-up. The circulation of flow is compared with the classic Longuet-Higgins (1983) solution and the time series of the set-up is considered for a 24h storm. Water infiltrates into the coastal aquifer on the upper part of the beach near the maximum run-up and exfiltration occurs on the lower part of the beach face near the breaking point
Oceanologia, Volume 56, pp 497-522; https://doi.org/10.5697/oc.55-3.497
Oceanologia, Volume 56, pp 411-443; https://doi.org/10.5697/oc.56-3.411
We analyse recent Mediterranean Sea surface temperatures (SSTs) and their response to global change using 1/4-degree gridded advanced very-high-resolution radiometer (AVHRR) daily SST data, 1982–2012. These data indicate significant annual warming (from 0.24°C decade−1 west of the Strait of Gibraltar to 0.51°C decade−1 over the Black Sea) and significant spatial variation in annual average SST (from 15°C over the Black Sea to 21°C over the Levantine sub-basin). Ensemble mean scenarios indicate that the study area SST may experience significant warming, peaking at 2.6°C century−1 in the Representative Concentration Pathways 85 (RCP85) scenario
Oceanologia, Volume 56, pp 477-496; https://doi.org/10.5697/oc.56-3.477
Oceanologia, Volume 56, pp 523-548; https://doi.org/10.5697/oc.56-3.523
Oceanologia, Volume 56, pp 583-602; https://doi.org/10.5697/oc.56-3.583
The zooplankton community structure in bays fluctuates as a result of anthropogenic activities in such waters. We focused on the short-term variability of a zooplankton community and compared its differences at the outflow of a nuclear power plant (ONPP), in a marine cage-culture area (MCCA) and in unpolluted waters (UW) in the south-west part of Daya Bay from 28 April to 1 June 2001. Environmental factors and zooplankton abundance differed significantly among stations at ONPP, MCCA and UW: high temperatures and a high zooplankton abundance occurred at ONPP, while a high chlorophyll a concentration and a low zooplankton abundance prevailed in MCCA. Statistical analysis revealed that the zooplankton diversity and abundance could be reduced by the activity of the marine cage-culture in a short time. Penilia avirostris made up an important component of the zooplankton in the study area, its abundance ranging widely from 16 to 7267 indiv. m-3 from April to June and peaking at the ONPP outflow. The outbreak of P. avirostris probably resulted from the combined effects of favourable water temperature, food concentration and its parthenogenetic behaviour
Oceanologia, Volume 56, pp 629-638; https://doi.org/10.5697/oc.56-3.629
Oceanologia, Volume 56, pp 497-521; https://doi.org/10.5697/oc.56-3.497
Oceanologia, Volume 56, pp 549-564; https://doi.org/10.5697/oc.56-3.549
Oceanologia, Volume 56, pp 565-581; https://doi.org/10.5697/oc.56-3.565
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Oceanologia, Volume 56, pp 603-628; https://doi.org/10.5697/oc.56-3.603
Oceanologia, Volume 56, pp 651-660; https://doi.org/10.5697/oc.56-3.651
Oceanologia, Volume 56, pp 661-666; https://doi.org/10.5697/oc.56-3.661
We report the first observation of large red cyanobacterial mats in the southern Baltic Sea. The mats (up to 2.5 m in diameter) were observed by SCUBA divers at 7.7 m depth on loamy sediments in the Gulf of Gdańsk in mid-November 2013. The main structure of the mat was formed by cyanobacteria Spirulina subsalsa Oersted ex Gomont; a number of other cyanobacteria, diatoms and nematode species were also present. After a few days in the laboratory, the red trichomes of S. subsalsa started to turn blue-green in colour, suggesting the strong chromatic acclimation abilities of this species.\ud
Oceanologia, Volume 56, pp 59-84; https://doi.org/10.5697/oc.56-1.059
Navigation charts of the post-glacial regions of Arctic fjords tend not to cover regions from which glaciers have retreated. Whilst research vessels can make detailed bathymetric models using multibeam echosounders, they are often too large to enter such areas. To map these regions therefore requires smaller boats carrying single beam echosounders. To obtain morphology models of equivalent quality to those generated using multibeam echosounders, new ways of processing data from single beam echosounders have to be found. The results and comprehensive analysis of such measurements conducted in Brepollen (Hornsund, Spitsbergen) are presented in this article. The morphological differentiation of the seafloor was determined by calculating statistical, spectral and wavelet transformation, fractal and median filtration parameters of segments of bathymetric profiles. This set of parameters constituted the input for Principal Component Analysis and then in the form of Principal Components for the Cluster Analysis. As a result of this procedure, three morphological classes are proposed for Brepollen: (i) steep slopes (southern Brepollen), (ii) flat bottoms (central Brepollen) and gentle slopes (the Storebreen glacier valley and the southern part of the Hornbreen glacier valley), (iii) the morphologically most diverse region (the central Storebreen valley, the northern part of the Hornbreen glacier valley and the north-eastern part of central Brepollen)
Oceanologia, Volume 56, pp 141-150; https://doi.org/10.5697/oc.56-1.141
Evadne anonyx, a new invasive Ponto-Caspian species, was detected for the first time in the Gulf of Gdańsk in the summer of 2006. Seven years probably elapsed from the first record of E. anonyx in the Baltic Sea (Gulf of Finland) to the first one in the Gulf of Gdańsk. Although the species was found at 10 out of 13 stations in rather low densities (not exceeding 6 indiv. m−3), all the developmental stages of E. anonyx were present (juveniles as well as adults – parthenogenetic females, gamogenetic females and males) in the plankton material investigated
Oceanologia, Volume 56, pp 151-158; https://doi.org/10.5697/oc.56-1.151
The present work reports the first record of Limnodrilus cervix in the south-eastern part of the Baltic Sea. A specimen of this North American species was found in 2010 in the Vistula Lagoon, near the village of Piaski (Poland). The distribution of other Nearctic Limnodrilus species in Europe is also presented
Formation and species composition of stormcast beach wrack in the Gulf of Riga, Baltic Sea **The study was supported by the EU Life+project MARMONI ‘Innovative approaches for marine biodiversity monitoring and assessment of conservation status of nature values in the Baltic Sea’, ESF grant No. 8980, Estonian target financed project SF0180104s08 and Institutional research funding IUT2-20 of the Estonian Research Council.
Oceanologia, Volume 56, pp 673-695; https://doi.org/10.5697/oc.56-4.673
Composition of stormcast beach wrack in the Gulf of Riga, Baltic Sea* doi:10.5697/oc.56-4.673 OCEANOLOGIA, 56 (4), 2014. pp. 673–695. ©C Copyright b
Oceanologia, Volume 56, pp 805-824; https://doi.org/10.5697/oc.56-4.805
The aim of this study was to characterise the introduced North American Harris mud crab Rhithropanopeus harrisii, which occurs in the Gulf of Gdańsk, Poland (southern Baltic Sea). Of the 920 specimens caught between 2006 and 2010, males and females made up 44 and 40% respectively, whereas juveniles (< 4.4 mm carapace width) comprised 16%. Overall carapace widths ranged from 1.96 mm to 21.40 mm (mean 9.03±4.11 mm). Ovigerous females (mean 11.12±2.76 mm) were present in the population from June to October. Most of the adult specimens collected (n=158) had carapace widths between 10.1 and 12.0 mm. The wet weight of R. harrisii varied from 0.005 to 4.446 g (mean 0.410 ± 0.569 g). Females exhibited a negative allometric increase in weight (b=2.77), males an isometric increase in weight (b=3.02). The condition factor (K) in R. harrisii varied from 0.02 to 0.08 (mean 0.05±0.01)
Oceanologia, Volume 56, pp 881-887; https://doi.org/10.5697/oc.56-4.881
Oceanologia, Volume 56, pp 291-306; https://doi.org/10.5697/oc.56-2.291
Climate-related variables in the Baltic region using Lake Onega as an example* doi:10.5697/oc.56-2.291 OCEANOLOGIA, 56 (2), 2014. pp. 291–306. ©C Copyright b
Oceanologia, Volume 56, pp 349-372; https://doi.org/10.5697/oc.56-2.349
The impact of ship traffic emissions in the Baltic Sea on deposition and airborne concentrations of nitrogen and sulphur compounds in the period 2008–2011 was studied using the Hilatar chemistry transport model with a 0.068° latitude-longitude resolution. An accurate ship emission inventory based on AIS (automatic identification system) security signals was used. The uncertainty of the European emission inventories are discussed, as is an inter-comparison of the Baltic Sea airborne load and concentrations with other model-based estimates and with air quality measurements and the effect of the EU sulphur directive for ship emissions on sulphate concentrations
Oceanologia, Volume 56, pp 125-139; https://doi.org/10.5697/oc.56-1.125
The aim of this study was to determine the occurrence, spatial distribution and abundance pattern of the Harris mud crab Rhithropanopeus harrisii in the Gulf of Gdańsk (southern Baltic Sea). Between 2006 and 2010, this species was found at 69 out of 129 sampling stations, at depths from 0 to 20m. Two main aggregations of the Harris mud crab were established: (1) in Puck Bay (max. density 19 indiv. 100m−2) and (2) in the Gdynia and Sopot area (max. density 5 indiv. 100m−2). 920 specimens were collected during the whole sampling period: 150 juveniles, 370 females and 400 males. The minimum measured carapace width was 1.96mm, the maximum 21.40mm (mean 9.03±4.11mm)
Oceanologia, Volume 56, pp 41-58; https://doi.org/10.5697/oc.56-1.041
The biometric characteristics and reproductive biology of the nereid polychaete Pseudonereis anomala were studied monthly from August 2009 to July 2010 at two ecologically different sites (Abu-Qir and El-Mex) on the Alexandria coast, south-eastern Mediterranean Sea. The maximum body length and weight showed different values at the two sites: 9.8 and 11.9cm, and 0.77 and 1.3g respectively. The formula of the length-weight relationship indicated allometric growth, whereas the regression equation between length to the 6th segment and weight reflected isometric growth. Immature individuals were the major component of the worm population at the two sites, making up 69.1% at Abu Qir and 66.9% at El Mex; the respective percentages of males and females at these sites were 5.8–8.1% and 22.8–27.3%. Spawning was observed all the year round with female fecundity conspicuously lower at Abu-Qir (annual average: 26556±999 eggs per female) than at El-Mex (annual average: 47 955±2916 eggs per female). However, oocyte size was greater at Abu Qir (diameter: up to 250μm) than at El Mex (diameter: up to 220μm)
Oceanologia, Volume 56, pp 85-106; https://doi.org/10.5697/oc.56-1.085
Two methods – in situ sediment trap experiments and an isotopic method based on measurements of 210Pb activities in the sediment cores taken near the traps – were applied for determining sediment deposition and sediment accumulation rates in the eastern part of Puck Bay. The sediment deposition rate (1.67mmyear−1) based on the in situ measurement was comparable with the sediment accumulation rate calculated using the Constant Flux:Constant Sedimentation Rate model for the isotopic method. The age of the sediment layers was determined with the Constant Rate of Supply model; the deepest layers had accumulated around 1900
Oceanologia, Volume 56, pp 167-189; https://doi.org/10.5697/oc.56-2.167
This paper introduces a newly established coupled atmosphere-ocean-ice system with the regional climate model COSMO-CLM and the ocean-sea-ice model NEMO for the North and Baltic Seas. These two models are linked via the OASIS3 coupler. Experiments with the new coupled system and with the stand-alone COSMO-CLM model forced by ERA-Interim re-analysis data over the period from 1985 to 1994 for the CORDEX Europe domain are carried out. The evaluation results of the coupled system show 2-m temperature biases in the range from −2.5 to 3K. Simulated 2-m temperatures are generally colder in the coupled than in the uncoupled system, and temperature differences vary by season and space. The coupled model shows an improvement compared with the stand-alone COSMO-CLM in terms of simulating 2-m temperature. The difference in 2-m temperature between the two experiments are explained as downwind cooling by the colder North and Baltic Seas in the coupled system
Characteristics of cyclones causing extreme sea levels in the northern Baltic Sea**The study was supported by the Estonian Ministry of Education and Research (IUT20-11 and Grant ETF9134) and by the EU Regional Development Foundation, Environmental Conservation and Environmental Technology R&D Programme Project No. 3.2.0801.12-0044.
Oceanologia, Volume 56, pp 241-258; https://doi.org/10.5697/oc.56-2.241
The basic parameters of extra-tropical cyclones in the northern Baltic are examined in relation to extreme sea level events at Estonian coastal stations between 1948 and 2010. The hypothesis that extreme sea level events might be caused not by one intense extra-tropical cyclone, as suggested by earlier researchers, but by the temporal clustering of cyclones in a certain trajectory corridor, is tested. More detailed analysis of atmospheric conditions at the time of the two most extreme cases support this concept: the sequence of 5 cyclones building up the extreme sea level within about 10days was very similar in structure and periodicity
Oceanologia, Volume 56, pp 307-326; https://doi.org/10.5697/oc.56-2.307
Studies of vertical coarse aerosol fluxes in the boundary layer over the Baltic Sea**This work was supported through the National Science Centre grant NN 306315536; support for this study was also provided by the project ‘Satellite Monitoring of the Baltic Sea Environment – SatBałtyk’ funded by European Union through European Regional Development Fund contract No. POIG 01.01.02-22-011/09.
Oceanologia, Volume 56, pp 697-710; https://doi.org/10.5697/oc.56-4.697
Oceanologia, Volume 56, pp 779-787; https://doi.org/10.5697/oc.56-4.779
This paper describes for the first time the gonad maturity stage of Eriocheir sinensis females (carapace width 55.20–78.10mm) collected in the autumns and winters of 2005–2012 in the Gulf of Gdańsk and Vistula Lagoon (southern Baltic Sea). Seventeen females had gonads in the penultimate stage, which indicates that spawning would shortly take place. Four other females had gonads in the last stage, which means they were already carrying eggs. These accounted, on average, for 17.9 ± 2.9% of female weight and were in the 3rd and 4th embryo developmental stage. The results show that the low salinity of southern Baltic Sea (≤ 7 PSU) permits mating and fertilization as well as embryo development in E. sinensis. It is still not clear, whether such a salinity level will enable hatching and the complete larval cycle
Diurnal variability of water vapour in the Baltic Sea region according to NCEP-CFSR and BaltAn65+ reanalyses**The survey was supported by the Estonian Science Foundation under a postdoctoral grant JD189, by European Social Fund’s Doctoral Studies and Internationalisation Programme DoRa and project SLOOM12073T, which are carried out by the Archimedes Foundation, and by the Estonian Radiation Climate project, funded by the European Regional Development Fund.
Oceanologia, Volume 56, pp 191-204; https://doi.org/10.5697/oc.56-2.191
Oceanologia, Volume 56, pp 205-222; https://doi.org/10.5697/oc.56-2.205
Oceanologia, Volume 56, pp 223-239; https://doi.org/10.5697/oc.56-2.223
Oceanologia, Volume 56, pp 259-290; https://doi.org/10.5697/oc.56-2.259
The purpose of this article is to analyse and describe the extreme characteristics of the water levels and illustrate them as the topography of the sea surface along the whole Baltic Sea coast. The general pattern is to show the maxima and minima of Baltic Sea water levels and the extent of their variations in the period from 1960 to 2010. A probability analysis is carried out on the annual sea level maxima and minima for 31 water level gauges in order to define the probability of occurrence of theoretical sea levels once in a specific number of years. The spatial distribution of sea levels for hundred-year maximum and minimum water levels is illustrated. Then, the number of storm surges for the accepted criteria are presented: these numbers increased in the 50-year period analysed. The final part of the work analyses some extreme storm events and calculates the static value and dynamic deformation of the sea surface by mesoscale, deep low-pressure systems
Could submarine groundwater discharge be a significant carbon source to the southern Baltic Sea?**The study reports the results obtained within the framework of the following projects: the statutory activities of the Institute of Oceanology Polish Academy of Sciences theme 2.2, research project No. 2012/05/N/ST10/02761 sponsored by the National Science Centre, and AMBER, the BONUS+EU FP6 Project.
Oceanologia, Volume 56, pp 327-347; https://doi.org/10.5697/oc.56-2.327
Groundwater discharge be a significant carbon source to the southern Baltic Sea?* doi:10.5697/oc.56-2.327 OCEANOLOGIA, 56 (2), 2014. pp. 327–347. ©C Copyright b
Oceanologia, Volume 56, pp 373-383; https://doi.org/10.5697/oc.56-2.373
Adapting flood preparedness tools to changing flood risk conditions: the situation in Poland⁎⁎The preparation of this paper was funded from the EU FP7 STAR-FLOOD Project (STrengthening And Redesigning European FLOOD risk practices: Towards appropriate and resilient flood risk governance arrangements). This project also provided funding for the author’s participation at the BALTEX Conference.
Oceanologia, Volume 56, pp 385-407; https://doi.org/10.5697/oc.56-2.385
Flooding is the most destructive natural hazard in the Baltic Sea Basin in general and in Poland in particular. The notion includes floods from rivers and mountain torrents, as well as floods from sea surges in coastal areas, and floods from sewage systems. There have been several large floods in Poland in the last century and in recent decades, with damage exceeding 1% of the Polish GDP. The spatial and temporal characteristics of the flood risk in Poland are reviewed and observations and projections of changes in the flood hazard in the country are discussed. Furthermore, flood defences and flood preparedness systems in Poland are examined, with particular reference to the European Union (EU) Floods Directive, which is being implemented in Poland, an EU country. Finally, the public debate on flood risk and flood preparedness is reviewed
Nutrient turnover at the hypoxic boundary: flux measurements and model representation for the bottom water environment of the Gulf of Riga, Baltic Sea**The study was supported by the ERAF project ‘Development of a mechanistic model of the Gulf of Riga ecosystem in support of an efficient national policy to ensure the protection of the Baltic Sea and to promote the sustainable use of its ecosystem’ (Ref. Nr. 2010/0287/2DP/22.214.171.124.0/10/APIA/VIAA/040) and the state research programme ‘Impact of climate change on Latvia’s water environment – KALME’.
Oceanologia, Volume 56, pp 711-735; https://doi.org/10.5697/oc.56-4.711
Regional algorithms for the estimation of chlorophyll and suspended matter concentration in the Gulf of Finland from MODIS-Aqua satellite data**This work was funded by the Russian Government (grant No. 11.G34.31.0078) for research under the supervision of the leading scientist at the Russian State Hydrometeorological University.
Oceanologia, Volume 56, pp 737-756; https://doi.org/10.5697/oc.56-4.737
Validation of algorithms for the retrieval of concentrations of chlorophyll (Chl) and total suspended matter (TSM) in the Gulf of Finland from satellite ocean colour data was carried out using field measurement data from summer 2012 and 2013. These data included spectral values of the remote sensing reflectance Rrs(λ), Chl and TSM concentrations. Testing of the existing algorithms (OC4v4, OC3M, and the Baltic regional algorithms developed by Polish specialists) showed that all of them overestimated Chl several times. The new regional algorithms were developed on the basis of measured values of Rrs(λ), Chl and TSM (40 stations in total). Direct comparison of Chl and TSM values, obtained from MODISAqua data with the algorithms developed here, with their in situ values showed reasonable agreement. The spatial distributions of Chl and TSM concentrations were constructed from MODIS-Aqua data. Errors of the atmospheric correction were analysed
Oceanologia, Volume 56, pp 757-778; https://doi.org/10.5697/oc.56-4.757
Oceanologia, Volume 56, pp 789-804; https://doi.org/10.5697/oc.56-4.789
During the 2009 and 2010 seasons Baltic herring (Clupea harengus membras L.) spawning grounds were investigated by SCUBA divers off the Lithuanian Baltic Sea coast. The most important spawning substrate was a hard bottom overgrown with red algae Furcellaria lumbricalis, but only 32.8% of potentially suitable spawning locations had herring eggs. Bottom geomorphological analysis using multibeam bathymetry revealed that the distribution of spawning beds is not random, but is determined rather by small-scale geomorphological features. The majority of the detected spawning locations were on local elevations characterised by 2.4 ± 1.1m depth differences and 4.8 ± 1.8 slopes