Oceanologia No. 62 (2) / 20

Contents

Original research article

Original research article


Significance of nutrient fluxes via submarine groundwater discharge in the Bay of Puck, southern Baltic Sea
Oceanologia 2020, 62(2), 117-125
https://doi.org/10.1016/j.oceano.2019.12.004

Beata Szymczycha*, Żaneta Kłostowska, Monika Lengier, Lidia Dzierzbicka-Głowacka
Institute of Oceanology, Polish Academy of Sciences, Sopot, Poland;
e-mail: beat.sz@iopan.gda.pl
*corresponding author

keywords: Biogeochemistry, SGD, Coastal zones, Return flux, Nitrogen, Phosphorous, Bay of Puck (Baltic Sea)

Received 29 August 2019, Revised 21 November 2019, Accepted 30 December 2019, Available online 10 January 2020.

Abstract

In this study, we collected submarine groundwater discharge (SGD) and seawater samples at six sites in the Bay of Puck, in the southern Baltic Sea, in order to estimate the nutrient distribution in groundwater affected areas. In addition, we estimated nutrient fluxes via SGD, including both fresh SGD (FSGD) and recirculated seawater SGD (RSGD), to the entire Bay of Puck. Phosphate (PO43−) concentrations varied significantly among study sites and seasons, while both ammonium (NH4+) and nitrates (NO3−) concentrations varied only seasonally. The N:P ratio indicated P limitation in most of the samples. The estimated seasonal and annual loads, via SGD, of both dissolved inorganic nitrogen (DIN; 9303 t yr−1) and PO43− (950 t yr−1), were the most significant source of nutrients to the Bay of Puck, and notably higher than quantified before (FSGD nutrient loads of 50 t yr−1 and 56 t yr−1 for DIN and PO43−, respectively). The SGD fluxes reported here indicate some of the highest rates of sediment-water fluxes reported in the Baltic Sea. These results suggest that SGD (both FSGD and RSGD) should be considered as source of chemical substances to the marine environment.
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Indian Ocean wind speed variability and global teleconnection patterns
Oceanologia 2020, 62(2), 126-138
https://doi.org/10.1016/j.oceano.2019.10.002

Mourani Sinha1,*, Somnath Jha2, Paromita Chakraborty3
1Department of Mathematics, Techno India University, Saltlake, Kolkata, India;
e-mail: mou510@gmail.com
2Department of Home, Swami Vivekananda State Police Academy, Barrackpore, India
3National Centre for Medium Range Weather Forecasting, Noida, Uttar Pradesh, India

keywords: Wind speed, Sea surface temperature, Monsoon, Wavelet coherence, Indian Ocean, Global teleconnection

Received 23 February 2019, Revised 9 October 2019, Accepted 11 October 2019, Available online 30 October 2019.

Abstract

The influence of the local sea surface temperature (SST) and remote ENSO (El Niño-Southern Oscillation) indices on the wind speed (WS) data were explored for the Indian Ocean region. Relationships among the parameters were studied using spatial correlation plots and significant correlation ranges. Two months (July and January) representing opposite monsoon phases were selected for analysis for the period 1950–2016. There was a significant negative correlation between WS and SST over the Bay of Bengal (BOB) during July. Although different ENSO indices correlated differently in different areas of the Indian Ocean, the region off the coast of Sri Lanka was most significantly teleconnected. The southwest monsoon locally impacted the WS and SST relationship and the WS parameter was remotely teleconnected in both the monsoon seasons. Further empirical orthogonal function (EOF) analysis was applied on the 67 years WS data of the BOB region to extract the dominant mode representing maximum variability of the total variance. The temporal pattern of the first principal component (PC1) of WS data was linked to the North Atlantic Oscillations in January and the Atlantic Multidecadal Oscillation in July respectively. The continuous wavelet power spectra of the PC1 of WS showed significant regions in the 2–4-year band resembling the ENSO variability. Wavelet coherence applied between PC1 of WS and the ENSO indices showed greatest values for January in the 8–16-year band and for July in the 0–4-year band. A close relationship was established between the WS variability in BOB and the ENSO indices.
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Element enrichment and provenance of the detrital component in Holocene sediments from the western Black Sea
Oceanologia 2020, 62(2), 139-163
https://doi.org/10.1016/j.oceano.2019.10.001

Vesselin M. Dekov1,2,*, Valentina Y. Darakchieva3, Kjell Billström4, C. Dieter Garbe-Schönberg5, George D. Kamenov6, Morgane Gallinari7, Lyubomir Dimitrov8, Olivier Ragueneau7, Ellen Kooijman4
1Tokyo University of Marine Science and Technology, Konan, Minato-ku, Tokyo, Japan;
e-mail: wdekov0@kaiyodai.ac.jp
2Department of Marine Geosciences, IFREMER, Plouzané, France
3Institute of Mineralogy and Crystallography, Bulgarian Academy of Sciences, Sofia, Bulgaria
4Department of Geosciences, Swedish Museum of Natural History, Stockholm, Sweden
5Institute of Geosciences, Marine Climate Research, University of Kiel, Kiel, Germany
6Department of Geological Sciences, University of Florida, Gainesville, FL, USA
7UMR CNRS/UBO 6539 LEMAR, European Institute for Marine Studies, Technopôle Brest-Iroise, Plouzané, France
8Institute of Oceanology, Bulgarian Academy of Sciences, Varna, Bulgaria
*corresponding author

keywords: Anoxic, Black Sea, Element enrichment, Sr-Nd-Pb-isotopes, Holocene

Received 12 August 2019, Revised 9 October 2019, Accepted 11 October 2019, Available online 30 October 2019.

Abstract

Concentrations of a large set of major and trace elements, and Sr, Nd and Pb isotope ratios were measured in Holocene sediments cored in the western deep Black Sea in order to unravel: (1) the controls of element enrichment, and (2) sources of the detrital component. The transition of the basin from oxic to euxinic resulted in enrichment or depletion in a number of elements in the deep-sea sediments. Authigenic Fe enrichment appears to depend on the amount of Fe mobilized from the sediment through the benthic redox shuttle mechanism and free H2S in the water column (degree of “euxinization”). Manganese enrichment is controlled by diagenetic reactions within the sediment: the dissolution of Mn minerals, Mn2+ diffusion upward and reprecipitation. Barium enrichment is also controlled by diagenetic reactions, sulfate reduction and methanogenesis, that take place above and below the sulfate-methane transition, respectively. The major part of V, Co, Ni, Cu, Zn, Cr, Mo, Cd and Sb is inferred to have co-precipitated with Fe in the euxinic deep waters and to have been incorporated into authigenic Fe-sulfides. Basin reservoir effect additionally influences the Mo enrichment. The U enrichment is interpreted to have a different origin in the two organic-rich stratigraphic units (II and I). It is inferred to be: (i) at the expense of the U inventory of the deepwater pool and a result of inorganic reduction of U at euxinic conditions in the lower Unit II; and (ii) at the expense of the U inventory of the surface water pool and a result of biogenic uptake and transfer to the sediment by the plankton in the upper Unit I. The high field strength elements are closely linked to the detrital component and their depletion in the organic-rich sediments reflects a dilution of the detrital component by the biogenic one. The enrichments of REE, Sn and Th are likely controlled by adsorption on clay minerals. Sr-Nd-Pb isotope compositions of the alumino-silicate component of the studied sediments are relatively uniform. They are most likely controlled by riverine suspended matter supplied mainly in the NW Black Sea (Danube Delta) and transported southward by marine currents, and to a lesser degree by suspended matter from the small rivers draining SE Bulgaria and NW Turkey. Wind-blown dust from the Sahara Desert appears to have a minor contribution to the alumino-silicate component of the sediments. The slight shift in the Pb isotopes in Unit I upper layers is possibly caused by the addition of anthropogenic Pb.
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Influence of climate change on the ice conditions of the Curonian Lagoon
Oceanologia 2020, 62(2), 164-172
https://doi.org/10.1016/j.oceano.2019.10.003

Darius Jakimavičius*, Diana Šarauskienė, Jūratė Kriaučiūnienė
Laboratory of Hydrology, Lithuanian Energy Institute, Kaunas, Lithuania;
e-mail: darius.jakimavicius@lei.lt
*corresponding author

keywords: Curonian lagoon, Ice indices, Ice duration, Ice thickness, Ice breakup, RCP scenarios

Received 28 June 2019, Revised 23 September 2019, Accepted 17 October 2019, Available online 31 October 2019.

Abstract

The Curonian Lagoon is a shallow freshwater lagoon of significant environmental value in the south-eastern part of the Baltic Sea. The objective of the study was to evaluate changes of ice indices (duration, thickness and breakup dates) of this lagoon and to assess their possible tendencies in the 21st century. A methodology was developed combining the assessment of past changes (1960–2017) of ice indices and their projections in the near (2021–2040) and far (2081–2100) future periods using a hydrometeorological database, statistical methods and regression analysis as well as regional climate models and RCP scenarios. Climate change has a considerable impact on ice conditions in the Curonian Lagoon. During the historical period of 1960–2017, the Curonian Lagoon was covered with ice for 72 days a year, ice thickness reached 23 cm, whereas ice breakup was observed in the middle of March on average. According to the different scenarios, in the near and far future periods, ice duration will last 35–45 and 3–34 days, respectively. Ice thickness is projected to be 13–15 cm in the near future, whereas, at the end of the century, it is expected to decline to 0–13 cm. In the past, the lagoon ice cover remained until the middle of the third decade of February. At the end of the 21st century, RCP8.5 scenario projects the most drastic shifts: the permanent ice cover might be absent, whereas short-term ice cover is expected to melt already in the beginning of January.
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Simulating tropical storms in the Gulf of Mexico using analytical models
Oceanologia 2020, 62(2), 173-189
https://doi.org/10.1016/j.oceano.2019.11.001

Mehdi Yaghoobi Kalourazi1, Seyed Mostafa Siadatmousavi1,*, Abbas Yeganeh-Bakhtiary1, Felix Jose2
1School of Civil Engineering, Iran University of Science and Technology, Narmak, Tehran, Iran;
e-mail: siadatmousavi@iust.ac.ir
2Department of Marine & Earth Sciences, Florida Gulf Coast University, Fort Myers, FL, USA
*corresponding author

keywords: Analytical wind model, H*Wind, Buoy data, Optimization, Hurricanes, Gulf of Mexico

Received 12 June 2019, Revised 6 November 2019, Accepted 7 November 2019, Available online 25 November 2019.

Abstract

Different analytical models have been evaluated for estimating wind speed of the tropical storm, where the storm-induced wind velocity is calculated as a function of distance from the center of the hurricane. For these models, different parameters such as maximum wind speed, a radius of the maximum wind, hurricane shape parameter, hurricane translation speed and the orientation of the trajectory, etc., affect the shape of a hurricane. Hurricanes Lili (2002), Ivan (2004), Katrina (2005), Gustav (2008) and Ike (2008) from the Gulf of Mexico were used for skill assessment. The maximum wind radius was calculated using significant wind radii (R34, R50 and R64) reported by the National Hurricane Center. Different formulas for calculating the radius of maximum wind speed were evaluated. The asymmetric wind field for each hurricane was generated using analytic methods and compared with in situ data from buoys in the Gulf of Mexico and the H*Wind data. Analytical models were able to predict high wind speed under tropical cyclone conditions with relatively high precision. Among the analytical models evaluated in this research, the model proposed by Holland et al. (2010) showed excellent results. Dynamical wind models such as NCEP/NARR provide wind speed with the coarse spatial resolution which is acceptable for far-field locations away from the hurricane eye. In contrast, analytical models were able to produce sufficiently reliable wind speed within a particular radius from the center of the hurricane. Therefore blending of dynamical and analytical models can be used to provide accurate wind data during hurricane passage in the Gulf of Mexico.
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Influence of the climatic variations in the wind waves parameters on the alongshore sediment transport
Oceanologia 2020, 62(2), 190-199
https://doi.org/10.1016/j.oceano.2019.11.002

Boris V. Divinsky*, Ruben D. Kosyan
Shirshov Institute of Oceanology RAS, Moscow, Russia;
e-mail: divin@ocean.ru
*corresponding author

keywords: Black Sea, Sediment transport, Wind waves, Swell, Numerical modeling

Received 9 September 2019, Revised 25 November 2019, Accepted 25 November 2019, Available online 7 December 2019.

Abstract

The purpose of this work was to analyze the influence of climatic variability of wind waves and swell parameters in the coastal zone on the sediment transport and to assess the contribution of the swell to the formation of alongshore fluxes. The object of research is the Anapa bay-bar (the Black Sea). Mathematical modeling has shown that in the Anapa bay-bar area the average annual wind waves and swell powers have significant interannual variability. For the period from 1979 to 2017, in the southern part of the bay-bar, there was a statistically significant decrease in the share of swell in the alongshore transport, directed from NW to SE, in the central part – an increase in the contribution of swell to the total sediment flow from SE to NW, in the northern part – probable increase in flows to NW and decrease – to SE. Such a dynamic is consistent, in general, with experimental observations of the processes of erosion and accumulation of beach-forming material along the Anapa bay-bar coastline. A separate description of the bottom sediment fluxes under the influence of wind waves and swell made it possible to explain the fluctuations of the coastline over a climatic period.
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Evaluation of carbon stock in the sediment of two mangrove species, Avicennia marina and Rhizophora mucronata, growing in the Farasan Islands, Saudi Arabia
Oceanologia 2020, 62(2), 200-213
https://doi.org/10.1016/j.oceano.2019.12.001

Ebrahem M.Eid1,2,*, Khaled M. Khedher3,4, Hamdi Ayed3,5, Muhammad Arshad6, Adel Moatamed7,8,9, Abir Mouldi3,5
1Department of Biology, College of Science, King Khalid University, Saudi Arabia;
e-mail: ebrahem.eid@sci.kfs.edu.eg, eeid@kku.edu.sa, ebrahem.eid@gmail.com
2Department of Botany, Faculty of Science, Kafr El-Sheikh University, Egypt
3Department of Civil Engineering, College of Engineering, King Khalid University, Saudi Arabia
4Department of Civil Engineering, High Institute of Technological Studies, Mrezgua University Campus, Tunisia
5Higher Institute of Transport and Logistics of Sousse, University of Sousse, Tunisia
6Department of Chemical Engineering, College of Engineering, King Khalid University, Saudi Arabia
7Department of Geography, College of Humanities, King Khalid University, Saudi Arabia
8Prince Sultan Bin Abdul-Aziz Center for Environment and Tourism Research and Studies, King Khalid University, Saudi Arabia
9Department of Geography, Faculty of Arts, Assiut University, Assiut, Egypt

keywords: Blue carbon, Carbon sequestration, Carbon stocks, Climate change, Coastal ecosystems

Received 12 October 2019, Revised 18 December 2019, Accepted 19 December 2019, Available online 6 January 2020.

Abstract

The aim of this study was to conduct the first comprehensive evaluation of carbon stock in the sediments of Avicennia marina (black mangrove) and Rhizophora mucronata (red mangrove) along the coastline of an arid region (Farasan Islands, Saudi Arabia). Such information is necessary for the development of any management plan for the mangrove ecosystems along the Saudi Red Sea islands and provide a rationale for the restoration of mangrove forests in Saudi Arabia. A. marina and R. mucronata locations showed significant (P < 0.001) differences in sediment bulk density (SBD) and sediment organic carbon (SOC) concentration with higher mean values for both in the sediments of A. marina. Considering the whole depth of sediment sampled (0–50 cm), the highest value of SOC stock (12.3 kg C m−2) was recorded at A. marina locations and the lowest (10.8 kg C m−2) at R. mucronata locations. Thus, the SOC stock of A. marina was greater than that of R. mucronata by 114.3%. Consequently, considering the rate of carbon sequestration and the area of mangrove forests (216.4 ha), the total carbon sequestration potential of mangroves in the Farasan Islands ranged between 10.3 Mg C yr−1 and 11.8 Mg C yr−1 for R. mucronata and A. marina locations, respectively. Thus, it is necessary to protect and restore these ecosystems for the sequestration of carbon and for their other valuable ecosystem services.
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Effects of oxytetracycline on growth and chlorophyll a fluorescence in green algae (Chlorella vulgaris), diatom (Phaeodactylum tricornutum) and cyanobacteria (Microcystis aeruginosa and Nodularia spumigena)
Oceanologia 2020, 62(2), 214-225
https://doi.org/10.1016/j.oceano.2019.12.002

Grzegorz Siedlewicz1,*, Adam Żak2, Lilianna Sharma1, Alicja Kosakowska1, Ksenia Pazdro1
1Department of Marine Chemistry and Biochemistry, Institute of Oceanology, Polish Academy of Sciences, Sopot, Poland;
e-mail: gsiedlewicz@iopan.gda.pl
2Department of Plant Physiology and Biotechnology, University of Gdańsk, Gdańsk, Poland
*corresponding author

keywords: Antibiotics, Cyanobacteria, Microalgae, Chlorophyll a fluorescence, Toxicity studies

Received 19 July 2019, Revised 24 December 2019, Accepted 27 December 2019, Available online 8 January 2020.

Abstract

The study aimed at measuring the influence of a wide range of oxytetracycline concentrations, with particular attention to the low levels of the antibiotic on cyanobacteria Microcystis aeruginosa and Nodularia spumigena, diatom Phaeodactylum tricornutum and the model green algae Chlorella vulgaris by conducting prolonged toxicity tests (lasting 10 days). Standard measurements (cell number, optical density, chlorophyll a concentration) were combined with photosynthetic parameters measurements. The obtained results show that concentrations of oxytetracycline present in the environment can affect tested microorganisms. It was found to decrease photosystem II efficiency and disrupt the photosynthesis process. A careful interpretation of photosynthetic parameters allowed a better understanding of the mode of action of oxytetracycline in relation to non-target photoautotrophic organisms like cyanobacteria and microalgae. In conclusion, it would appear that the use of standard chronic toxicity tests (72 h) does not allow to accurately and reliably assess the chronic impact of bioactive compounds including drugs and their metabolites on water organisms. On this basis, we recommend the application of extended duration tests.
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Effects of Global Climate Oscillations on Intermonthly to Interannual Variability of Sea levels along the English Channel Coasts (NW France)
Oceanologia 2020, 62(2), 226-242
https://doi.org/10.1016/j.oceano.2020.01.001

Imen Turki*, Nicolas Massei*, Benoit Laignel*, Hassan Shafiei*
UMR CNRS 6143 – Continental and Coastal Morphodynamics ‘M2C’, University of Rouen, Mont-Saint-Aignan Cedex, France;
e-mail: imen.turki@univ-rouen.fr, nicolas.massei@univ-rouen.fr, benoit.laignel@univ-rouen.fr, hassan.shafiei@univ-rouen.fr
*corresponding author

keywords: Sea level, Extreme surges, Multiscale variability, Storms, Climate oscillations, Multiresolution analysis

Received 25 May 2019, Revised 19 January 2020, Accepted 20 January 2020, Available online 5 February 2020.

Abstract

This work examines the multiscale variability in sea level along the English Channel coasts (NW France) using a wavelet multiresolution decomposition of water level values and climate oscillations in order to gain insights in the connection between the global atmospheric circulation and the local-scale variability of the monthly extreme surges. Changes in surges have exhibited different oscillatory components from the intermonthly (~3–6-months) to the interannual scales (~1.5-years, ~2–4-years, ~5–8-years) with mean explained variances of ~40% and ~25% of the total variability respectively. The correlation between the multiresolution components of surges and 28 exceptional stormy events with different intensities has revealed that energetic events are manifested at all timescales while moderate events are limited to short scales.
By considering the two hypotheses of (1) the physical mechanisms of the atmospheric circulation change according to the timescales and (2) their connection with the local variability improves the prediction of the extremes, the multiscale components of the monthly extreme surges have been investigated using four different climate oscillations (Sea Surface Temperature (SST), Sea-Level Pressure (SLP), Zonal Wind (ZW), and North Atlantic Oscillation (NAO)); results show statistically significant correlations with ~3–6-months, ~1.5-years, ~2–4-years, and ~5–8-years, respectively. Such physical links, from global to local scales, have been considered to model the multiscale monthly extreme surges using a time-dependent Generalized Extreme Value (GEV) distribution. The incorporation of the climate information in the GEV parameters has considerably improved the fitting of the different timescales of surges with an explained variance higher than 30%. This improvement exhibits their nonlinear relationship with the large-scale atmospheric circulation.
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