Oceanologia No. 64 (3) / 22

Contents

Original research article

Short communication

Original research article


Detecting food limitation of bacterial growth during dilution experiments
Oceanologia 2022, 64(3), 405-416
https://doi.org/10.1016/j.oceano.2022.02.001

Krzysztof Rychert
Institute of Biology and Earth Sciences, Pomeranian University, Słupsk, Poland;
e-mail: krychert@wp.pl

keywords: Bacterial growth, Bacterivory, Organic matter, Oxygen consumption, Coastal zone, Baltic Sea

Received 25 December 2020, Revised 25 January 2022, Accepted 7 February 2022, Available online 22 February 2022, Version of Record 13 July 2022.

Abstract

The dilution method is typically applied to estimate the growth and mortality rates of phytoplankton, but it is also used to study bacterioplankton. The method comprises creating a gradient of dilutions to reduce the encounter rates between bacterivores and bacteria, thus allowing for estimations of bacterial growth and grazing pressure exerted on the bacteria. However, the manipulations involved in the method can lead to biased results. In this study, 12 dilution experiments performed in the coastal zone of the Baltic Sea were accompanied by additional measurements capable of detecting possible artefacts. Only six measurements performed during spring and summer (March–August) produced results that were free of artefacts and were statistically significant. During fall and winter (October–February) measurements were unsuccessful because of food limitation of bacterial growth during experimental incubation. Twice (in September and October) bacterial growth and grazing mortality rates were underestimated because grazing pressure was not successfully removed. The study demonstrated that 24-hour and five-day oxygen consumption measurements incorporated into dilution experiments permitted estimating the fraction of biodegradable organic matter used during incubation, and, thus, detecting the food limitation of bacterial growth.
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Shoreline change rate dynamics analysis and prediction of future positions using satellite imagery for the southern coast of Kuwait: A case study
Oceanologia 2022, 64(3), 417-432
https://doi.org/10.1016/j.oceano.2022.02.002

Najeeb S. Aladwani
Department of Earth and Environmental Sciences, Faculty of Science, Kuwait University, Kuwait;
e-mail: Najeeb.aladwani@ku.edu.kw

keywords: Shoreline change rates, Shoreline position extraction, Future shoreline position, EPR and LRR models, Al-Khiran project

Received 24 September 2021, Revised 26 January 2022, Accepted 8 February 2022, Available online 24 February 2022, Version of Record 13 July 2022.

Abstract

The studied shoreline extends 73 kilometers, starting from the Kuwait-Saudi Arabia borders northward. This work represents a limited work that analyses the historical shoreline positions. Five-dates satellite images along a period of 35 years between 1986 and 2021 were used to calculate the historical shoreline change rates and predict future shoreline positions in 2030 and 2050. First, the historical shoreline was extracted using the Normalized Difference Wader index (WI 2015). Then, the shoreline change rates were quantified statistically using the End Point Rate (EPR) and the Linear Regression Rate (LRR) models of the Digital Shoreline Analysis System (DSAS) tool in ArcMap. It has been found that the maximum erosion rate is –9.73 m/year, and the highest accretion is 10.88 m/year. Also, the positions of shorelines in the year 2030 and 2050 were predicted and defined on the map, with mapping of gain and loss surfaces. The results defined the most stable areas for future development and the areas needing urgent protection. It has been found that the resulting model can be affected by the topographical changes of the beaches due to human activities, where the coast alongside the Al-Khiran project will be eroded and accreted less than predicted because of the presence of protection facilities.
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Distribution of benthic macroinvertebrates across a reed stand in a brackish Baltic lagoon
Oceanologia 2022, 64(3), 433-444
https://doi.org/10.1016/j.oceano.2022.02.004

Krzysztof Pawlikowski*, Ryszard Kornijów
National Marine Fisheries Research Institute, Gdynia, Poland;
e-mail: kpawlikowski@mir.gdynia.pl
*corresponding author

keywords: Vistula Lagoon, Littoral zone, Zoobenthos, Trophic guilds, Macrophytes

Received 12 October 2021, Revised 14 January 2022, Accepted 21 February 2022, Available online 7 March 2022, Version of Record 13 July 2022

Abstract

The role of reeds in the functioning of ecosystems and their significance for zoobenthos in the coastal lagoons is poorly understood. We hypothesise that next to the spatial zonal differentiation of abiotic factors in the apparently homogeneous habitat of reeds, benthic macroinvertebrate fauna is also unevenly distributed, and differs in taxonomic and functional diversity, as well as density and biomass across the reed stand. The research was carried out in the Vistula Lagoon (southern Baltic) along three designated sectors arranged parallel to the shoreline and differing in distance from the shore and depth. Mean density of reed stems in the analysed stand was within the range of values reported from different American and European wetlands. Regardless of the location within the reeds and the season, the fauna was dominated by detritivorous Tubificinae and larvae of Chironomidae. The highest diversity, density, and biomass of fauna were found in the middle littoral zone, and the lowest in the outer zone adjacent to the open water. The presented data support our hypothesis predicting the existence of a spatial variation pattern in the composition and distribution of macroinvertebrates in response to the changing zonal habitat conditions within the reed stand.
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Tropical cyclone intensity modulated by the oceanic eddies in the Bay of Bengal
Oceanologia 2022, 64(3), 445-456
https://doi.org/10.1016/j.oceano.2022.02.005

Navaneeth Kodunthirapully Narayanaswami1,2,*, Venkatesan Ramasamy1
1Ocean Observation Systems, National Institute of Ocean Technology (NIOT), Chennai, India;
e-mail: nkn968@gmail.com
2Anna University, Guindy Campus, Chennai, India

keywords: Phailin, Fani, Eddy feedback factor, Cold-core eddy, Warm-core eddy

Received 22 June 2021, Revised 16 January 2022, Accepted 20 February 2022, Available online 7 March 2022, Version of Record 13 July 2022.

Abstract

The Bay of Bengal, an affluent region for mesoscale oceanic eddies, is also home to devastating tropical cyclones. The intensity modulation of two cyclones, Phailin (2013) and Fani (2019), in the Bay of Bengal by the oceanic eddies is studied. The intensities of both the cyclones rapidly changed after transiting over mesoscale eddies. The surface and subsurface oceanic conditions before and during the passage of the two cyclones were analysed. During Phailin (Fani), the cyclonic (anticyclonic) eddy resulted in significant (weak) sea surface temperature cooling due to the shallow (deep) D26 isotherm. Wind shear estimates revealed that it had no (minor) effect on the weakening (intensification) of Phailin (Fani). The analysis of enthalpy fluxes during the two cyclones has shown that during Phailin (Fani), the latent heat flux supply was reduced (enhanced) by 20 W m−2 (30 W m−2) over the regions of the cyclonic (anticyclonic) eddy due to significant (weak) sea surface temperature cooling. The case study of cyclone interaction with mesoscale oceanic eddies has shown that a thorough understanding of mesoscale eddies is vital for improving the accuracy of the cyclone intensity forecasts.
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Numerical study of coastal wave profiles at the sandy beaches of Nowshahr (Southern Caspian Sea)
Oceanologia 2022, 64(3), 457-472
https://doi.org/10.1016/j.oceano.2022.03.001

Seyed Masoud Mahmoudof*, Mohammadali Lotfi Takami
Iranian National Institute for Oceanography and Atmospheric Sciences (INIOAS), Tehran, Iran;
e-mail: m_mahmoudof@inio.ac.ir
*corresponding author

keywords: SWASH Model, Caspian Sea, Wave evolution, Infragravity waves, Short wind-waves

Received 14 November 2021, Revised 11 February 2022, Accepted 9 March 2022, Available online 20 March 2022, Version of Record 13 July 2022.

Abstract

This study aimed to investigate the capability of the one-dimensional (1D) mode of the Simulating WAves till SHore (SWASH), as a non-hydrostatic wave-flow model with six vertical layers, to reproduce the cross-shore wave evolution. For this purpose, the given model was initially calibrated for wave energy and the outputs were then verified with the field data measured at the Southern Caspian Sea. The calibration coefficients obtained for wave breaking are significantly less than the ones which have been mostly reported in previous studies for the two-dimensional (2D) mode of the SWASH. Although the reproduced wave height parameters are generally in good accordance with the field observations, the period parameters and the number of waves are overestimated and underestimated by the model, respectively. Moreover, the inaccuracies at the shallow stations are worse than at the transitional depths. The overestimation in both the reproduced energy of infragravity waves (IG) and their wavelength along with the underestimation in the wind-wave energy content are also among the factors responsible for the model deficiencies. The findings have revealed that the overestimation of the reproduced IG waves is the main reason for the underestimation of the breaking dissipation rate for irregular wave trains in the 1D mode. Therefore, more intensive breaking dissipation via selecting lower coefficient values is necessary to exhaust a certain energy content from longer waves in the 1D mode. This approach ultimately induces an over-dissipation of short wind-waves.
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Hydrographic variation in a tropical coral reef system: The Veracruz Reef System, Gulf of Mexico
Oceanologia 2022, 64(3), 473-488
https://doi.org/10.1016/j.oceano.2022.03.002

David Salas-Monreal1,*, Rosalinda Monreal-Jimenez2, Victor Kevin Contreras-Tereza3, Maria Adela Monreal-Gomez4, David Alberto Salas-de-Leon4, Mayra Lorena Riveron-Enzastiga5
1Institute of Marine Sciences and Fisheries, Universidad Veracruzana, Boca del Rio, Mexico;
e-mail: davsalas@uv.mx
2Postgraduate in Earth Sciences, National Autonomous University of Mexico (UNAM), Ciudad Universitaria, Mexico City, Mexico
3Hydrometeorology Subcoordination, Mexican Institute of Water Technology, Jiutepec, Mexico
4Institute of Marine Sciences and Limnology, National Autonomous University of Mexico (UNAM), Ciudad Universitaria, Mexico City, Mexico
5Science Department, Noordwijk International College, Veracruz, Mexico
*corresponding author

keywords: Coral reefs, Veracruz Reef System, Reef corridor of the southwestern Gulf of Mexico, Chlorophyll-a concentrations, Hydrographic seasonal variability, T-S diagrams

Received 8 July 2021, Revised 1 March 2022, Accepted 9 March 2022, Available online 23 March 2022, Version of Record 13 July 2022.

Abstract

Three thousand forty-one profiles of temperature, salinity, density, dissolved oxygen, nitrogen and chlorophyll-a were used to study their seasonal variation on a tropical coral reef system, located in the central part, of the reef corridor of the southwestern Gulf of Mexico. The results revealed three seasons according to their hydrographic variations; the northerly wind season from September to April; the dry season from May to June; and the rainy season from July to August. The results of the density ratio during the dry season were ∼1.25 on average, while during the rainy season it had an average value of ∼0.62. Thus, the pycnocline was more influenced by the halocline during the rainy season and by the thermocline during the dry season. There was also an evident variation in chlorophyll-a concentration over the water column, which was not evident in the surface layer. During the summer (rainy season), dissolved oxygen was related to chlorophyll-a concentration; while, during the winter (northern wind season), these values were related to the vertical mixing of the water column due to wind stress. There was evidence of cooler ocean water intrusion into the Veracruz Reef System during the spring-summer season below ∼10 m. Finally, a second halocline, pycnocline, and nitrocline were found near ∼30 m depth during the rainy season..
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Distribution of anisakid nematodes in the muscle tissue of cod (Gadus morhua) from the Norwegian Sea
Oceanologia 2022, 64(3), 489-502
https://doi.org/10.1016/j.oceano.2022.03.003

Katarzyna Nadolna-Ałtyn1,*, Magdalena Podolska1, Joanna Pawlak1, Beata Szostakowska2
1National Marine Fisheries Research Institute, Gdynia, Poland;
e-mail: knadolna@mir.gdynia.pl
2Medical University of Gdańsk, Gdynia, Poland
* corresponding author

keywords: Anisakis, Pseudoterranova, Atlantic cod, Gadus morhua, North Atlantic

Received 31 May 2021, Revised 13 December 2021, Accepted 14 December 2021, Available online 29 December 2021, Version of Record 3 May 2022.

Abstract

Atlantic cod (Gadus morhua) is an important commercial fish species on the world market. The aim of our studies was to explore the presence, intensity of infection and distribution of the zoonotic nematodes of the different genera of Anisakidae in the muscle tissue of G. morhua from the Norwegian Sea. Cod from fishing areas FAO IIa1 (n = 50) and FAO IIa2 (n = 56) were sampled in March 2017. The unskinned flesh of each fish was examined using a white-light transilluminator. Collected parasites were identified to the genus level, and a subsample was identified using molecular methods. We found a higher prevalence of infection with Anisakis than with Pseudoterranova in the musculature of cod from both fishing areas. In FAO IIa1, a lower prevalence of infection with Pseudoterranova was recorded (14%) than in FAO IIa2 (∼39%). However, the intensity of infection was higher (53) in FAO IIa2 than in FAO IIa1 (8 parasites per fish). The opposite was found with Anisakis (prevalence 88% in FAO IIa1 and ∼55% in FAO IIa2, intensity up to 30 and up to 25 parasites per fish respectively). Most Anisakis larvae were present in the belly flaps (predominantly the left side), while Pseudoterranova spp. were dispersed with descending frequency in belly flaps, dorsal fillet and caudal fillet. Molecular identification revealed the presence of A. simplex (s.s.), P. decipiens (s.s.) and P. krabbei in both areas, and a hybrid of P. decipiens and P. krabbei in FAO IIa2.
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Mud volcano as a feature of emergence in Caspian Sea
Oceanologia 2022, 64(3), 503-513
https://doi.org/10.1016/j.oceano.2022.03.006

Danial Ghaderi, Maryam Rahbani*
Faculty of Marine Science and Technology, University of Hormozgan, Bandar Abbas, Iran;
e-mail: m_rahbani@hormozgan.ac.ir, maryamrahbani@yahoo.com
*corresponding author

keywords: Dashli Island, Daşlı ada, Mud volcano, Eruption, Emergence, Sentinel-1, Sentinel-2

Received 2 September 2021, Revised 10 March 2022, Accepted 18 March 2022, Available online 1 April 2022, Version of Record 13 July 2022.

Abstract

An eruption occurred on Dashli Island, 75 km from Baku, on 4th of July 2021, at 21:51 local time. The island is known as the mud volcano and has a history of eruption. We suspected that mud volcano eruption causes emergence on this island. Thus, the effect of this 2021 eruption is investigated using a remote sensing technique. Processed Sentinel-1 and 2 images are employed for this aim. We considered pre- and post-eruption scenarios to evaluate the effect of this eruption on the island. Satellite image classification is used to calculate shoreline changes. Results show that Dashli Island with an area of about 8.55 ha before eruption is now expanded to about 21.8 ha (about 155% increase). The DInSAR method is used to estimate the ground displacement of the island. According to the results, a two-year-displacement before the eruption was between 0.18 and 0.2 m, while a five-month-displacement after the eruption is estimated to be between 0.32 and 0.4 m. Considering ground displacement pre- and post-eruption we estimated 62000 m3 land gaining, due to emergence. We concluded that mud volcano can be counted as a feature of emergence in Dashli Island.
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A coupled model for sediment transport dynamics and prediction of seabed morphology with application to 1DH/2DH coastal engineering problems
Oceanologia 2022, 64(3), 514-534
https://doi.org/10.1016/j.oceano.2022.03.007

Vasileios Afentoulis1,*, Andreas Papadimitriou1, Kostas Belibassakis2, Vasiliki Tsoukala1
1Laboratory of Harbour Works, Department of Water Resources and Environmental Engineering, School of Civil Engineering, National Technical University of Athens, Greece;
e-mail: af.vasilis@gmail.com
2School of Naval Architecture and Marine Engineering, National Technical University of Athens, Athens, Greece
*corresponding author

keywords: Sediment transport, Coastal dynamics, Boussinesq Wave Model, Numerical modeling, Coastal structures

Received 12 August 2021, Revised 28 February 2022, Accepted 18 March 2022, Available online 4 April 2022, Version of Record 13 July 2022.

Abstract

Salinity and pH play a fundamental role in structuring spatial patterns of physical properties, biota, and biogeochemical processes in the estuarine ecosystem. In this study, the influence of salinity-pH gradient and carbonate system on polychaete diversity in Ennore, Uppanar, Vellar, and Kaduvaiyar estuaries was investigated. Water and sediment samples were collected from September 2017 to August 2018. Univariate and multivariate statistical analyses were employed to define ecological status. Temperature, salinity, pH, and partial pressure of carbon-di-oxide varied between 21 and 30°C; 29 and 39 ppt; 7.4 and 8.3; and 89.216 and 1702.558 µatm, respectively. PCA and CCA results revealed that DO, chlorophyll, carbonate species, and sediment TOC have a higher influence on polychaete community structure. Forty-two species such as Ancistrosyllis parva, Cossura coasta, Eunice pennata, Euclymene annandalei, Lumbrineris albidentata, Capitella capitata, Prionospio cirrifera, P. pinnata, P. cirrobranchiata, and Notomastus sp. were found dominantly in all estuaries. Shannon index values ranged between 1.619 (UE-1) and 3.376 (VE-2). Based on these findings, high levels of carbonate species and low pH have a greater impact on polychaete diversity and richness values. The results of the AMBI Index revealed that stations UE-1, UE-2, UE-3 in Uppanar, EC-1, EC-2 in Ennore indicate “moderately disturbed”, while other stations are under the “slightly disturbed” category. This trend was quite evident in M-AMBI as well.
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The decline of Svalbard land-fast sea ice extent as a result of climate change
Oceanologia 2022, 64(3), 535-545
https://doi.org/10.1016/j.oceano.2022.03.008

Jacek A. Urbański1,*, Dagmara Litwicka2
1GIS Laboratory, Institute of Oceanography, University of Gdańsk, Gdynia, Poland;
e-mail: jacek.urbanski@ug.edu.pl
2Institute of Oceanology, Polish Academy of Sciences, Sopot, Poland
*corresponding author

keywords: Svalbard, Fast ice, Warming, Machine learning, Random Forest

Received 14 July 2021, Revised 23 March 2022, Accepted 24 March 2022, Available online 8 April 2022, Version of Record 13 July 2022.

Abstract

The Svalbard Archipelago has experienced some of the most severe temperature increases in the Arctic in the last three decades. This temperature rise has accelerated sea-ice melting along the coast of the archipelago, thus bringing changes to the local environment. In view of the importance of the near-future distribution of land-fast sea ice along the Svalbard coast, the available observation data on the ice extent between 1973 and 2018 are used herein to create a random forest (RF) model for predicting the daily ice extent and its spatial distribution according to the cumulative number of freezing and thawing degree days and the duration of the ice season. Two RF models are constructed by using either regression or classification algorithms. The regression model makes it possible to estimate the extent of land-fast ice with a root mean square error (RMSE) of 800 km2, while the classification model creates a cluster of submodels in order to forecast the spatial distribution of land-fast ice with less than 10% error. The models also enable the reconstruction of the past ice extent, and the prediction of the near-future extent, from standard meteorological data, and can even analyze the real-time spatial variability of land-fast ice. On average, the minimum two-monthly extent of land-fast sea ice along the Svalbard coast was about 12,000 km2 between 1973 and 2000. In 2005–2019, however, the ice extent declined to about 6,000 km2. A further increase in mean winter air temperatures by two degrees, which is forecast in 10 to 20 years, will result in a minimum two-monthly land-fast ice extent of about 1,500 km2, thus indicating a trend of declining land-fast ice extent in this area.
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Short communication


Effects of air-sea drag coefficient on estimating wind stress using wind statistics
Oceanologia 2022, 64(3), 546-552
https://doi.org/10.1016/j.oceano.2022.03.004

Dag Myrhaug*, Hong Wang, Lars Erik Holmedal, Bernt J. Leira
Department of Marine Technology, Norwegian University of Science and Technology (NTNU), Trondheim, Norway;
e-mail: dag.myrhaug@ntnu.no
*corresponding author

keywords: Wind stress, Drag coefficient, North Atlantic, Northern North Sea, Wind statistics, Stochastic method

Received 23 November 2021, Revised 21 February 2022, Accepted 17 March 2022, Available online 31 March 2022, Version of Record 13 July 2022.

Abstract

This article addresses the effects of the air-sea drag coefficient on estimation of wind stress based on wind statistics. This is achieved by applying the same wind stress parameterizations chosen by Wrobel-Niedzwiecka et al. (2019) together with mean wind speed statistics from three locations in the North Atlantic and one location in the Northern North Sea. The expected values and the variances of the wind stress are provided. This study is complementary to that of Wrobel-Niedzwiecka et al. (2019), also demonstrating different results depending on the drag coefficient formula used.
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