Oceanologia No. 58 (2) / 16

Contents

Original research article

Short communications

Original research article


On the nonlinear internal waves propagating in an inhomogeneous shallow sea
Oceanologia 2016, 58(2), 59-70
http://dx.doi.org/10.1016/j.oceano.2016.01.005

Stanisław R. Massel
Institute of Oceanology of the Polish Academy of Sciences,
Sopot, Poland
e-mail: smas@iopan.gda.pl

keywords: Internal waves; Energy flux conservation; Bottom friction; Shearing instability; Wave breaking

Received 6 November 2015, Accepted 22 January 2016, Available online 16 February 2016

Abstract

A concept of conservation of energy flux for the internal waves propagating in an inhomogeneous shallow water is examined. The emphasis is put on an application of solution of the Korteweg–de Vries (KdV) equation in a prescribed form of the cnoidal and solitary waves. Numerical simulations were applied for the southern Baltic Sea, along a transect from the Bornholm Basin, through the Słupsk Sill and Słupsk Furrow to the Gdańsk Basin. Three-layer density structure typical for the Baltic Sea has been considered. An increase of wave height and decrease of phase speed with shallowing water depth was clearly demonstrated. The internal wave dynamics on both sides of the Słupsk Sill was found to be different due to different vertical density stratification in these areas. The bottom friction has only negligible influence on dynamics of internal waves, while shearing instability may be important only for very high waves. Area of possible instability, expressed in terms of the Richardson number Ri, is very small, and located within the non-uniform density layer, close to the interface with upper uniform layer. Kinematic breaking criteria have been examined and critical internal wave heights have been determined.
full, complete article - PDF (2316 K)

An integrated wave modelling framework for extreme and rare events for climate change in coastal areas – the case of Rethymno, Crete
Oceanologia 2016, 58(2), 71-89
http://dx.doi.org/10.1016/j.oceano.2016.01.002

Vasiliki K. Tsoukala1,*, Michalis Chondros1, Zacharias G. Kapelonis2, Nikolaos Martzikos1, Archodia Lykou3, Kostas Belibassakis2, Christos Makropoulos3
1Laboratory of Harbor Works, National Technical University of Athens, Athens, Greece;
e-mail: vtsouk@hydro.civil.ntua.gr
*corresponding author
2School of Naval Architecture and Marine Engineering, National Technical University of Athens, Athens, Greece
3 Laboratory of Hydrology & Water Resources Utilization, National Technical University of Athens, Athens, Greece

keywords: Climate change; Wave run-up; Wave overtopping; Storm events; Coastal flooding

Received 23 July 2015, Accepted 8 January 2016, Available online 29 January 2016

Abstract

Coastal floods are regarded as among the most dangerous and harmful of all natural disasters affecting urban areas adjacent to the shorelines. Rapid urbanization combined with climate change and poor governance often results in significant increase of flood risk, especially for coastal communities. Wave overtopping and wave run-up are the key mechanisms for monitoring the results of coastal flooding and as such, significant efforts are currently focusing on their predicting. In this paper, an integrated methodology is proposed, accounting for wave overtopping and wave run-up under extreme wave scenarios caused by storm surges. By taking advantage of past and future climatic projections of wind data, a downscaling approach is proposed, utilizing a number of appropriate numerical models than can simulate the wave propagation from offshore up to the swash zone. The coastal zone of Rethymno in Greece is selected as a case study area and simulations of wave characteristics with the model SWAN for the period 1960–2100 in the offshore region are presented. These data are given as boundary conditions to further numerical models (MIKE21 PMS and HD) in order to investigate the spatial evolution of the wave and the hydrodynamic field in intermediate and shallow waters. Finally, the calculated wave height serves as input to empirical formulas and time dependent wave propagation models (MIKE21 BW) to estimate the wave run-up and wave overtopping (EurOtop). It is suggested that the proposed procedure is generic enough to be applicable to any similar region.
full, complete article - PDF (8228 K)

Curonian Lagoon drainage basin modelling and assessment of climate change impact
Oceanologia 2016, 58(2), 90-102
http://dx.doi.org/10.1016/j.oceano.2016.01.003

Natalja Čerkasova1, Ali Ertürk1,2, Petras Zemlys1, Vitalij Denisov3, Georg Umgiesser1,4,*
1Open Access Centre for Marine Research, Klaipeda, Lithuania
2Department of Freshwater Biology, Istanbul University, Istanbul, Turkey
3Faculty of Marine Technology and Natural Sciences, Klaipeda University, Klaipeda, Lithuania
4 ISMAR-CNR, Institute of Marine Sciences, Venezia, Italy;
e-mail: georg.umgiesser@ismar.cnr.it
*corresponding author
keywords: Drainage basin modelling; SWAT; Curonian Lagoon; Nemunas basin; Climate change

Received 8 September 2015, Accepted 12 January 2016, Available online 9 February 2016

Abstract

The Curonian Lagoon, which is the largest European coastal lagoon with a surface area of 1578 km2 and a drainage area of 100,458 km2, is facing a severe eutrophication problem. With its increasing water management difficulties, the need for a sophisticated hydrological model of the Curonian Lagoon's drainage area arose, in order to assess possible changes resulting from local and global processes. In this study, we developed and calibrated a sophisticated hydrological model with the required accuracy, as an initial step for the future development of a modelling framework that aims to correctly predict the movement of pesticides, sediments or nutrients, and to evaluate water-management practices. The Soil and Water Assessment Tool was used to implement a model of the study area and to assess the impact of climate-change scenarios on the run-off of the Nemunas River and the Minija River, which are located in the Curonian Lagoons drainage basin. The models calibration and validation were performed using monthly streamflow data, and evaluated using the coefficient of determination (R2) and the Nash-Sutcliffe model efficiency coefficient (NSE). The calculated values of the R2 and NSE for the Nemunas and Minija Rivers stations were 0.81 and 0.79 for the calibration, and 0.679 and 0.602 for the validation period. Two potential climate-change scenarios were developed within the general patterns of near-term climate projections, as defined by the Intergovernmental Panel on Climate Change Fifth Assessment Report: both pessimistic (substantial changes in precipitation and temperature) and optimistic (insubstantial changes in precipitation and temperature). Both simulations produce similar general patterns in river-discharge change: a strong increase (up to 22%) in the winter months, especially in February, a decrease during the spring (up to 10%) and summer (up to 18%), and a slight increase during the autumn (up to 10%).
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Modeling the buoyancy-driven Black Sea Water outflow into the North Aegean Sea
Oceanologia 2016, 58(2), 103-116
http://dx.doi.org/10.1016/j.oceano.2015.12.003

Nikolaos Kokkos, Georgios Sylaios*
Department of Environmental Engineering, Democritus University of Thrace, Xanthi, Greece;
e-mail: gsylaios@env.duth.gr
*corresponding author

keywords: Hydrodynamic model; Remote sensing data; Model validation; Potential energy anomaly; North Aegean Sea

Received 30 July 2015, Accepted 29 December 2015, Available online 20 January 2016

Abstract

A three-dimensional numerical model was applied to simulate the Black Sea Water (BSW) outflux and spreading over the North Aegean Sea, and its impact on circulation and stratification–mixing dynamics. Model results were validated against satellite-derived sea surface temperature and in-situ temperature and salinity profiles. Further, the model results were post-processed in terms of the potential energy anomaly, ϕ, analyzing the factors contributing to its change. It occurs that BSW contributes significantly on the Thracian Sea water column stratification, but its signal reduces in the rest of the North Aegean Sea. The BSW buoyancy flux contributed to the change of ϕ in the Thracian Sea by 1.23 × 10−3 W m−3 in the winter and 7.9 × 10−4 W m−3 in the summer, significantly higher than the corresponding solar heat flux contribution (1.41 × 10−5 W m−3 and 7.4 × 10−5 W m−3, respectively). Quantification of the ϕ-advective term crossing the north-western BSW branch (to the north of Lemnos Island), depicted a strong non-linear relation to the relative vorticity of Samothraki Anticyclone. Similar analysis for the south-western branch illustrated a relationship between the ϕ-advective term sign and the relative vorticity in the Sporades system. The ϕ-mixing term increases its significance under strong winds (>15 m s−1), tending to destroy surface meso-scale eddies.
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Spatial distribution and diet of larval snailfishes (Liparis fabricii, Liparis gibbus, Liparis tunicatus) in the Canadian Beaufort Sea
Oceanologia 2016, 58(2), 117-123
http://dx.doi.org/10.1016/j.oceano.2015.12.001

Wojciech Walkusz1,2,*, Joclyn E. Paulic1, Sally Wong1, Sławomir Kwaśniewski2, Michael H. Papst1, James D. Reist1
1Fisheries and Oceans Canada, Freshwater Institute, Winnipeg, Canada;
e-mail: walwo@iopan.gda.pl , Joclyn.Paulic@dfo-mpo.gc.ca , Sally.Wong@dfo-mpo.gc.ca , Jim.Reist@dfo-mpo.gc.ca
*corresponding author
2Polish Academy of Sciences, Institute of Oceanology, Sopot, Poland;
e-mail: kwas@iopan.gda.pl

keywords: Beaufort Sea; Fish larvae; Liparis; Snailfish; Diet

Received 3 July 2015, Accepted 8 December 2015, Available online 29 December 2015

Abstract

This paper presents information on diet and distribution of larval snailfishes from the genus Liparis on the Canadian Beaufort Sea Shelf. In this study, 153 larval snailfishes of three species, Liparis fabricii, L. gibbus and L. tunicatus, were collected during 4 summer cruises (2003–2005, 2007). The majority of the larvae were either in flexion or post-flexion stage, and some were in pre-flexion stage. Liparis larvae appeared to be generalists in terms of diet and fed on a wide range of planktonic organisms. Pre-flexion larvae fed on small copepods (mainly adult stages of Triconia borealis). As larvae grew their diet shifted towards larger copepods (copepodids III/IV of Calanus hyperboreus, copepodids II–IV of Calanus glacialis and females of Metridia longa) and amphipods (Themisto libellula). Remarkably, larvaceans Oikopleura spp. and pelagic snails Limacina helicina made up a substantial part of the larval diet. This paper contributes to the knowledge on arctic larval fishes and to the ongoing efforts regarding Canadian Beaufort Sea ecosystem modeling.
full, complete article - PDF (905 K)

Scale-dependent environmental control of mesozooplankton community structure in three aquaculture subtropical bays of China
Oceanologia 2016, 58(2), 124-134
http://dx.doi.org/10.1016/j.oceano.2015.11.002

Dong Sun1, Zhensheng Liu1, Chunsheng Wang1,2,*
1Laboratory of Marine Ecosystem and Biogeochemistry, Second Institute of Oceanography,
State Oceanic Administration, Hangzhou, PR China
2State Key Laboratory of Satellite Ocean Environment Dynamics, Second Institute of Oceanography,
State Oceanic Administration, Hangzhou, PR China;
e-mail: wang-sio@163.com
*corresponding author

keywords: Zooplankton; Aquaculture; Pollution effects; Multivariate analysis; Subtropical bays

Received 30 November 2014, Accepted 9 November 2015, Available online 17 December 2015

Abstract

Most subtropical bays of China have been under heavy pollution since the late 1990s, mainly because of the rapid development of aquaculture and discharge of industrial and agricultural wastewater. Some projects were conducted to investigate the zooplankton community in these bays, but those studies were less focused on the relationship between spatial structure of mesozooplankton community and environmental variables in/among bays. The mesozooplankton community structures in relation to physical, chemical and biological variables were studied in three subtropical bays of China with seasons and different spatial scales during 2000 and 2002–2003. Data were collected on temperature (T), salinity (S), concentration of chlorophyll a (Chl a), pH, dissolved oxygen (DO), soluble reactive phosphate (SRP), dissolved inorganic nitrogen (DIN), chemical oxygen demand (COD), suspended particle material (SPM) and mesozooplankton taxonomic abundances. Correlation analysis showed that the main environmental factors correlated to the total abundance of mesozooplankton in these subtropical bays were Chl a, temperature, COD and SRP. Multivariate analysis indicated that DO, Chl a and temperature were the principal factors in influencing spatial differentiation of zooplankton community structure in the inter-bay scale. At the within-bay scale, the influencing factors were different among bays; the main factors were physical variables for Xiangshan Bay and Sanmen Bay, while chemical variables for Yueqing Bay, respectively. The results revealed that the environmental variables that affected spatial structure of mesozooplankton community were different at inter-bay scale and within-bay scales, and zooplankton community was more influenced by chemical (e.g. nutrients/ammonia) variables when under serious eutrophication condition, while it would be more influenced by physical variables (temperature/salinity) when under less eutrophic conditions.
full, complete article - PDF (1249 K)

Assessment of recent and chalcolithic period environmental pollution using Mytilus galloprovincialis Lamarck, 1819 from Yarimburgaz Cave, the northern Marmara Sea and Bosphorus coasts
Oceanologia 2016, 58(2), 135-149
http://dx.doi.org/10.1016/j.oceano.2016.01.001

Ipek F. Barut1,*, Engin Meriç2, M. Baki Yokeş3
1 Institute of Marine Sciences and Management, Istanbul University, Istanbul, Turkey;
e-mail: barutif@istanbul.edu.tr
*corresponding author
2 Moda Hüseyin Bey Sokak, Istanbul, Turkey
3 Dept. of Molecular Biology and Genetics, Haliç University, Istanbul, Turkey

keywords: Chalcolithic period; Geochemistry; Mytilus galloprovincialis shells; Northern Marmara Sea and Bosphorus coasts; Yarimburgaz Cave

Received 5 August 2015, Accepted 6 January 2016, Available online 5 February 2016

Abstract

Marine or freshwater mussel species are found in large quantities around populated areas and accumulate metals in aquatic systems. Therefore, these organisms are used to monitor environmental pollution. Mytilus galloprovincialis is a generally accepted bioindicator of metal pollution and is used in this study. The aim of this study is to determine the changes in the environmental conditions since antiquity. M. galloprovincialis shells were used to monitor Chalcolithic pollution levels in Yarimburgaz Cave, one of the oldest settlements in Europe. Recent samples were collected from 12 stations on the coasts of the Northern Marmara Sea and the Bosphorus between May–September 2004. The environmental pollution substantially changed over the last 7500 years. The comparison of the geochemical characteristics of the environmental pollution observed in the Chalcolithic period and today revealed that pollution from both household and industrial chemicals has increased in Istanbul.
full, complete article - PDF (3310 K)

Short communications


Addendum to “Sea spray aerosol flux estimation based on long-term variation of wave statistics”: estimation based on long-term variation of wind statistics
Oceanologia 2016, 58(2), 150-153
http://dx.doi.org/10.1016/j.oceano.2015.11.003

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

keywords: Sea spray aerosol flux; Whitecap coverage; Mean wind speed; Wind statistics

Received 1 July 2015, Accepted 27 November 2015, Available online 23 December 2015

Abstract

This note provides estimates of the mean whitecap coverage and the mean sea spray aerosol flux based on long-term wind statistics from the Northern North Sea. Here the improved sea spray aerosol production flux model by Callaghan (2013) is used. The results are compared with those in Myrhaug et al. (2015) based on long-term wave statistics from the Northern North Sea and the North Atlantic.
full, complete article - PDF (293 K)

The quagga mussel (Dreissena rostriformis bugensis Andrusov, 1897) – another Ponto-Caspian dreissenid bivalve in the southern Baltic catchment: the first record from the Szczecin Lagoon
Oceanologia 2016, 58(2), 154-159
http://dx.doi.org/10.1016/j.oceano.2015.12.002

Adam Woźniczka1,*, Brygida Wawrzyniak-Wydrowska2, Teresa Radziejewska2, Anna Skrzypacz2
1National Marine Fisheries Research Institute, Research Station in Świnoujście,
Świnoujście, Poland;
e-mail: awozniczka@mir.gdynia.pl
*corresponding author
2 Institute of Marine and Coastal Sciences, University of Szczecin,
Szczecin, Poland

keywords: Dreissena rostriformis bugensis; Baltic Sea; Szczecin Lagoon; Invasive species

Received 22 May 2015, Accepted 10 December 2015, Available online 11 January 2016

Abstract

In 2014, a non-indigenous dreissenid bivalve, the quagga mussel (Dreissena rostriformis bugensis Andrusov, 1897) was for the first time recorded in the Szczecin Lagoon. This was also the first record of the species in the Baltic Sea catchment. The quagga mussel was found to accompany the zebra mussel (Dreissena polymorpha), a non-indigenous bivalve already firmly established in the Lagoon. As indicated by the new immigrant's estimated abundance (4000.0 ± 355.44 ind. m−2) and the zebra mussel to quagga mussel abundance ratio (about 60:40), the immigration of D. rostriformis bugensis to the Lagoon can be regarded as successful. The quagga mussel has already formed a strong and reproducing population which co-occurs with that of the zebra mussel in the area.
full, complete article - PDF (855 K)