Oceanologia No. 60 (4 / 18)


Contents


Original research article


Short communications


Original research article



Deposition, return flux, and burial rates of nitrogen and phosphorus in the sediments of two high-Arctic fjords
Oceanologia 2018, 60(4), 431-445
https://doi.org/10.1016/j.oceano.2018.05.001

Katarzyna Koziorowska*, Karol Kuliński, Janusz Pempkowiak
Institute of Oceanology, Polish Academy of Sciences, Sopot, Poland;
e-mail: kkozio@iopan.gda.pl
*corresponding author

keywords: Hornsund, Kongsfjorden, Sedimentary nitrogen and phosphorus, Pore water, Concentrations, Nutrients

Received 4 April 2018, Accepted 4 May 2018, Available online 18 May 2018.

Abstract

The aim of this study was to determine the burial rates of nitrogen (N) and phosphorus (P) in the sediments of two high-latitude fjords: Hornsund and Kongsfjorden (Spitsbergen). Both deposition to sediments and the return flux from sediments to the water column of the various species of these elements were, therefore, quantified. The burial rate was then calculated as the difference between deposition and return flux. The required concentrations of N and P species were measured in surface sediments, in pore water extracted from the sediments, and in the above-bottom water at sampling stations situated along the axes of the fjords..
Annual deposition to sediments ranged between 2.3–8.3 g m−2 for N and 0.9–2.8 g m−2 for P. The nitrogen return fluxes ranged from 0.12 to 1.46 g m−2 y−1. At most stations, the N flux was predominantly of dissolved organic (about 60–70%) rather than inorganic N. The P return flux varied between 0.01 and 0.11 g m−2 y−1, with organic species constituting 60–97%. The N and P burial rates differed between fjords: 2.3–7.9 g N m−2 y−1 and 0.9–2.8 g P m−2 y−1 in Hornsund vs. 0.9–1.3 N g m−2 y−1 and 1.0–1.2 g P m−2 y−1 in Kongsfjorden. This was accompanied by a different efficiency of N and P burial – higher in Hornsund than in Kongsfjorden, in both cases. This suggests differences in the quality and quantity of N and P organic species deposited to sediments and therefore differences in the intensity of their mineralization and/or decomposition.
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Spatiotemporal changes in the concentration and composition of suspended particulate matter in front of Hansbreen, a tidewater glacier in Svalbard
Oceanologia 2018, 60(4), 446-463
https://doi.org/10.1016/j.oceano.2018.03.001

Mateusz Moskalik1,*, Joanna Ćwiąkała1, Witold Szczuciński2, Aleksander Dominiczak2, Oskar Głowacki1, Kacper Wojtysiak1, Piotr Zagórski3
1Institute of Geophysics, Polish Academy of Sciences, Warszawa, Poland;
e-mail: mmosk@igf.edu.pl
*corresponding author
2Institute of Geology, Adam Mickiewicz University in Poznań, Poznań, Poland
3Faculty of Earth Sciences and Spatial Management, Maria Curie-Skłodowska University, Lublin, Poland

keywords: Seasonality, Suspended particulate matter, Particulate organic matter, Tidewater glacier, Fjord, Svalbard

Received 31 July 2017, Accepted 19 March 2018, Available online 5 April 2018.

Abstract

Tidewater glaciers supply large amounts of suspended particulate matter (SPM) and freshwater to fjords and affect oceanographic, sedimentological and biological processes. Our understanding of these processes, is usually limited to the short summer season. Here, we present the results of a one-year-long monitoring of the spatial variability in SPM characteristics in a context of oceanographic and meteorological conditions of a glacial bay next to Hansbreen, a tidewater glacier in Hornsund (southern Spitsbergen). The observed range of SPM concentrations was similar to ranges measured in other sub-polar glaciated fjords, especially in Svalbard. The major source of SPM is the meltwater discharge from the glacier. The maximum water column-averaged SPM concentrations did not correlate with peaks in freshwater discharge and were observed at the beginning of the autumn season, when the fjord water transitioned from stratified to fully mixed. The observed spatiotemporal variations in the total SPM, particulate organic matter (POM) and particulate inorganic matter (PIM) are likely controlled by a combination of factors including freshwater supply, water stratification and circulation, bathymetry, the presence of sea ice, biological productivity and sediment resuspension. During the ablation season, the SPM maximum concentrations were located within the upper water layer, whereas during the winter and spring, the greatest amounts of SPM were concentrated in deeper part. Thus, typical remote sensing-based studies that focus on SPM distributions may not reflect the real SPM levels. POM and PIM concentrations were correlated with each other, during most of the time suggesting that they may have a common source.
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Partitioning of solar radiation in Arctic sea ice during melt season
Oceanologia 2018, 60(4), 464-477
https://doi.org/10.1016/j.oceano.2018.03.002

Peng Lu1,*, Bin Cheng2, Matti Leppäranta3, Zhijun Li1
1State Key Laboratory of Coastal and Offshore Engineering, Dalian University of Technology, Dalian, China;
e-mail: lupeng@dlut.edu.cn, bin.cheng@fmi.fi, matti.lepparanta@helsinki.fi, lizhijun@dlut.edu.cn
*corresponding author
2Finnish Meteorological Institute, Helsinki, Finland;
3Institute of Atmospheric and Earth Sciences, University of Helsinki, Helsinki, Finland;

keywords: Arctic sea ice, Melt pond, Radiation transfer, Mass balance, Numerical modelling

Received 28 December 2017, Accepted 22 March 2018, Available online 10 April 2018.

Abstract

The partitioning of solar radiation in the Arctic sea ice during the melt season is investigated using a radiative transfer model containing three layers of melt pond, underlying sea ice, and ocean beneath ice. The wavelength distribution of the spectral solar irradiance clearly narrowed with increasing depth into ice, from 350–900 nm at the pond surface to 400–600 nm in the ocean beneath. In contrast, the net spectral irradiance is quite uniform. The absorbed solar energy is sensitive to both pond depth (Hp) and the underlying ice thickness (Hi). The solar energy absorbed by the melt pond (Ψp) is proportional only to Hp. However, the solar energy absorbed by the underlying ice (Ψi) is more complicated due to the counteracting effects arising from the pond and ice to the energy absorption. In September, Ψp decreased by 10% from its August value, which is attributed to more components in the shortwave band (<530 nm) of the incident solar radiation in September relative to August. The absorption coefficient of the sea ice only enhances the absorbed energy in ice, while an increase in the ice scattering coefficient only enhances the absorbed energy in the melt pond, although the resulted changes in Ψp and Ψi are smaller than that in the albedo and transmittance. The energy absorption rate with depth depends strongly on the incident irradiance and ice scattering, but only weakly on pond depth. Our results are comparable to previous field measurements and numerical simulations. We conclude that the incident solar energy was largely absorbed by the melt pond rather than by the underlying sea ice.
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Acid volatile sulphide estimation using spatial sediment covariates in the Eastern Upper Gulf of Thailand: Multiple geostatistical approaches
Oceanologia 2018, 60(4), 478-487
https://doi.org/10.1016/j.oceano.2018.03.003

Pasicha Chaikaew1,3,*, Penjai Sompongchaiyakul2,3
1Department of Environmental Science, Faculty of Science, Chulalongkorn University, Bangkok, Thailand;
e-mail: pasicha.c@chula.ac.th
*corresponding author
2Department of Marine Science, Faculty of Science, Chulalongkorn University, Bangkok, Thailand
3Center of Excellence on Hazardous Substance Management, Chulalongkorn University, Bangkok, Thailand

keywords: Spatial estimation, Acid volatile sulphide, Sediment, Geostatistical analysis, Gulf of Thailand

Received 6 October 2017, Accepted 26 March 2018, Available online 12 April 2018.

Abstract

Acid volatile sulphide (AVS), one of the most reactive phases in sediments, is a crucial link in explaining a dynamic biogeochemical cycle in a marine ecosystem. Research gaps exist in describing the spatial variation of AVS and interconnections with sediment covariates in the Eastern Upper Gulf of Thailand. Measurements of AVS and auxiliary parameters followed the standard protocol. A comparison of ordinary kriging (OK), cokriging (CK), and regression kriging (RK) performance was evaluated based on the mean absolute error (MAE) and root mean square error (RMSE). The concentrations of AVS ranged from 0.003 to 0.349 mg g−1 sediment dry weight. Most parameters contained short range spatial dependency except for oxidation–reduction potential (ORP) and pH. The AVS tended to be both linearly and non-linearly related to ORP and readily oxidisable organic matter (ROM). The RK model, using inputs from the tree-based model, was the most robust of the three kriging methods. It is suggested that nonlinear interactions should be taken into account when predicting AVS concentration, and it is expected that this will further increase the model accuracy. This study helps establish a platform for ecological health and sediment quality guidelines.
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Bio-optical trends of seas around Turkey: An assessment of the spatial and temporal variability
Oceanologia 2018, 60(4), 488-499
https://doi.org/10.1016/j.oceano.2018.03.004

Fethi Bengil1,*, Sinan Mavruk2
1Faculty of Marine Sciences & Technology, Iskenderun Technical University, Hatay, Turkey;
2Institute of Marine Sciences, Middle East Technical University. Erdemli, Mersin, Turkey
e-mail: fethibengil@gau.edu.tr
*corresponding author

keywords: Trend analysis, Chlorophyll-a, Colored dissolved organic matter, Particulate backscattering, Ecosystem dynamics

Received 23 October 2017, Accepted 27 March 2018, Available online 13 April 2018.

Abstract

Until present, bio-optical characteristics and their variations in the eastern Mediterranean and Black Sea have rarely been studied. In order to characterize the basic features of bio-optical variables found in the seas surrounding Turkey, remotely sensed data sets covering the period between September 1997 and March 2017 were studied for the purpose of this research. Chlorophyll-a concentration (CHL), absorption coefficient by colored dissolved organic matter (CDOM) and particulate backscattering coefficient (BBP) were both evaluated to describe their recent linear and non-linear inter-annual patterns in the sub regions of the northern Levantine Sea (LS), the eastern Aegean Sea (AS), the Marmara Sea (MS) and the southern Black Sea (BS). The results determined a highly significant and decreasing trend of CHL in the Black Sea, whilst most other regions from the seas around Turkey displayed non-significant trends. The analysis indicated that the seas around Turkey can be clustered into two regions based on their bio-optical properties; one being the Black Sea and Marmara Sea, and the second cluster being the Aegean Sea and Levantine Sea.
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Some characteristic wave energy dissipation patterns along the Polish coast
Oceanologia 2018, 60(4), 500-512
https://doi.org/10.1016/j.oceano.2018.04.001

Grzegorz Różyński*, Piotr Szmytkiewicz
Institute of Hydro-Engineering, Polish Academy of Sciences, Gdańsk, Poland;
e-mail: grzegorz@ibwpan.gda.pl, P.Szmytkiewicz@ibwpan.gda.pl
*corresponding author

keywords: Coastal morphology, Wave energy dissipation, Equilibrium profiles, Data-driven modelling, Signal processing

Received 25 October 2017, Accepted 10 April 2018, Available online 25 April 2018.

Abstract

The paper analyses cross-shore bathymetric profiles between Władysławowo (km 125 of the national coastal chainage) and Lake Sarbsko (km 174) commissioned in 2005 and 2011 by coastal authorities for monitoring purposes. The profiles, spaced every 500 m, cover beach topography from dune/cliff tops through the emerged beach to a seabed depth of about 15 m. They were decomposed by signal processing techniques to extract their monotonic components containing all major modes of the variability of beach topography. They are termed empirical equilibrium profiles and can be used for straightforward assessment of wave energy dissipation rates. Three characteristic patterns of wave energy dissipation were thus identified: one associated with large nearshore bars and several zones of wave breaking; a second, to which the equilibrium beach profile concept can be applied; and a third, characterized by mixed behaviour. Interestingly, most profiles showed significant seabed variations beyond the nearshore depth of closure – this phenomenon requires comprehensive studies in future.
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Ecological assessment of heavy metals in the grey mangrove (Avicennia marina) and associated sediments along the Red Sea coast of Saudi Arabia
Oceanologia 2018, 60(4), 513-526
https://doi.org/10.1016/j.oceano.2018.04.002

Dhafer A. Alzahrani1, El-Metwally M. Selim2, Mohsen M. El-Sherbiny3,4,*
1Department of Biological Sciences, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia
2Department of Soil Sciences, Faculty of Agriculture, Damietta University, Damietta, Egypt
3Marine Biology Department, Faculty of Marine Sciences, King Abdulaziz University, Jeddah, Saudi Arabia
4Marine Biology Department, Faculty of Science, Suez Canal University, Ismailia, Egypt;
*corresponding author
e-mail: ooomar@kau.edu.sa

keywords: Mangrove, Avicennia marina, Heavy metals, Pollution indices, Sediment quality, Red Sea

Received 6 September 2017, Accepted 12 April 2018, Available online 30 April 2018.

Abstract

Mangroves play an integral role as a metal accumulator in tropical and subtropical marine ecosystems. Twenty-one sets of sediment samples and portions of mangroves were collected along the Saudi Arabian coast of the Red Sea to assess the accumulation and ecological risks of heavy metals. Results showed that the following mean concentrations of heavy metals in sediments: Cr (46.14 μg g−1 ± 18.48) > Cu (22.87 μg g−1 ± 13.60) > Ni (21.11 μg g−1 ± 3.2) > Pb (3.82 μg g−1 ± 2.46) > Cd (0.75 μg g−1 ± 0.87). The maximum concentrations of the studied metals were above the threshold effect level, indicating a limited impact on the respective ecosystems. The maximum concentration of Cd exceeded its toxic effect threshold, revealing a harmful risk to biota in the sediments. Based on metallo-phytoremedation, biological concentration factors were >1, suggesting that Avicennia marina can accumulate heavy metals, especially Cr and Pb. The translocation factor was above the known worldwide average. The geo-accumulation index revealed that sediments in mangrove areas ranged from moderately to heavily contaminated with Cd at Al-Haridhah and moderately contaminated at South Jeddah, Rabigh, Duba, and the wastewater treatment station near Jazan. The ecological risk index revealed that Cd could pose a relatively very high risk to the mangrove ecosystem. The present study emphasized the possibility of establishing a framework for the management of the coastal aquatic ecosystems along the Red Sea coast of Saudi Arabia.
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Narrowband shortwave minima of multispectral reflectance as indication of algal blooms associated with the mesoscale variability in the Brazil-Malvinas Confluence
Oceanologia 2018, 60(4), 527-543
https://doi.org/10.1016/j.oceano.2018.04.003

Genrik S. Karabashev*, Marina A. Evdoshenko
Laboratory of Ocean Optics, Shirshov Institute of Oceanology RAS, Moscow, Russia;
e-mail: genkar@mail.ru
*corresponding author

keywords: Algae, Bloom, Pigments, Reflectance spectrum, MODIS, Brazil-Malvinas Confluence

Received 5 February 2018, Accepted 13 April 2018, Available online 30 April 2018.

Abstract

We examine the narrowband shortwave minima (NSM) of multispectral reflectance as indication of mesoscale algal blooms. They are frequent in the Brazil-Malvinas confluence zone (BMCZ) where our testing site (TS) belongs. Its MODIS A images of December 2008 and 2014 were the source of initial data. Classification of reflectance spectra in these images revealed that the TS look from space was determined by the most populated cluster of pixels having the only NSM at 443 nm. We divided this cluster into sub-clusters by maximum wavelengths λmax from 412 to 555 nm and retrieved the estimates of λmax (proxy for abundance of colored dissolved organic matter (CDOM)), chl_a (MODIS chlorophyll), Rrs (555) (turbidity proxy), and CALH (NSM-based chlorophyll) on a pixel-by-pixel basis. This allowed us to demonstrate: (1) the NSM magnitude at 443 nm peaked in mesoscale structures, (2) CALH was consistent with chlorophyll in the BMCZ waters samples, (3) positive linear correlation of Rrs (555) and CALH was characteristic of the TS waters at any λmax, (4) the MODIS chl_a was overestimated when λmax > 488 nm, (5) localization and outlines of mesoscale structures agreed well in the fields of pairs Rrs(555) – CALH and λmaxchl_a, but not in the CALHchl_a pair. The NSM-based chlorophyll CALH outperformed the standard chl_a determinations in exactness because the CALH is insensitive to CDOM. This is advantageous when studying the Case 1 waters of intensive mesoscale variability where chlorophyll co-exists with the CDOM from eddy-induced blooms.
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Primary productivity in the Gulf of Riga (Baltic Sea) in relation to phytoplankton species and nutrient variability
Oceanologia 2018, 60(4), 544-552
https://doi.org/10.1016/j.oceano.2018.04.005

Ingrida Purina*, Atis Labucis, Ieva Barda, Iveta Jurgensone, Juris Aigars
*corresponding author
Latvian Institute of Aquatic Ecology, Riga, Latvia;
e-mail: ingrida.purina@lhei.lv
*corresponding author

keywords: Primary production, New production, Mesodinium rubrum, Aphanizomenon flosaquae, Gulf of Riga, Baltic Sea

Received 8 January 2018, Accepted 23 April 2018, Available online 8 May 2018.

Abstract

The seasonal patterns of primary production, phytoplankton biomass, chlorophyll a, and nutrients were investigated in the central part of the Gulf of Riga (Baltic Sea) during 2011 and 2012. Annual primary productivity in the gulf was in the range of 353.4–376.2 gC m−2. Maximum carbon fixation rates occurred during the phytoplankton spring bloom from April to May when the winter nutrient pool was rapidly exhausted, suggesting the use of regenerated nutrients already in spring. The new production calculated on the draw-down of nitrates amounted to 51.80% of spring net community production. The production rates during summer were considerably lower owing to the availability of only regenerated nutrients and limited nitrogen fixation. Autumn was established as the least productive season. In autumn despite the elevated nutrient concentrations, the increasingly limited light hindered photosynthetic activity. Species governing the nutrient fluxes and the productivity of the Gulf of Riga are the diatom species responsible for new production in spring. The photosynthetic ciliate Mesodinium rubrum ((Lohmann) Hamburger & Buddenbrock 1911) prevailed in all seasons and significantly correlated with elevated productivity, while diazotrophic cyanobacteria Aphanizomenon flosaquae (Ralfs ex Bornet & Flahault 1886) contributed to new production in the summer nutrient regenerating system.
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Short communications



The structure of macrozoobenthic communities as an environmental status indicator in the Gulf of Gdańsk (the Outer Puck Bay)
Oceanologia 2018, 60(4), 553-559
https://doi.org/10.1016/j.oceano.2018.05.002

Jan Warzocha*, Sławomira Gromisz, Tycjan Wodzinowski, Lena Szymanek
Department of Fisheries Oceanography and Marine Ecology, National Marine Fisheries Research Institute, Gdynia, Poland;
e-mail: janw@mir.gdynia.pl
*corresponding author

keywords: Macrozoobenthos, Long-term changes, Hypoxia

Received 13 March 2017, Accepted 7 May 2018, Available online 18 May 2018.

Abstract

An attempt is made to use long-term (1979–2014) macrobenthos data series to derive insights on changes in abiotic conditions and on potential effects of long-term macrobenthos variability on food availability for fish and wintering waterfowl. The data were collected from a small embayment, protected as a NATURA 2000 area, functioning as a fishing ground important for the local community and as a site of diverse commercial developments. The analysis showed a drastic reduction of the macrobenthos abundance and biomass, which could have been related to oxygen deficiency; on the other hand, recolonisation processes have also been observed.
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