Oceanologia No. 61 (3 / 19)


Contents


Original research article

Short communication


Original research article



Effect of drag coefficient formula choice on wind stress climatology in the North Atlantic and the European Arctic
Oceanologia 2019, 61(3), 291-299
https://doi.org/10.1016/j.oceano.2019.02.002

Iwona Wróbel-Niedźwiecka*, Violetta Drozdowska, Jacek Piskozub
Institute of Oceanology, Polish Academy of Sciences, Sopot, Poland;
e-mail: iwrobel@iopan.gda.pl
*corresponding author

keywords: EDrag coefficient, European Arctic, North Atlantic, Parameterizations

Received 13 December 2018, Accepted 26 February 2019, Available online 9 March 2019.

Abstract

Interactions between the atmosphere and the ocean determine boundary conditions for physical and biogeochemical processes in adjacent boundary layers, and the ocean surface is a complex interface where all air-sea fluxes take place and is a crucial valuable for ocean circulation and the ecosystem. We have chosen to study the differences between the relevant or most commonly used parameterizations for drag coefficient (CD) for the momentum transfer values, especially in the North Atlantic (NA) and the European Arctic (EA), using them together with realistic wind field. We studied monthly mean values of air-sea momentum flux resulting from the choice of different drag coefficient parameterizations, adapted them to momentum flux (wind stress) calculations using wind fields, sea-ice masks, as well as integrating procedures. We compared the resulting spreads in momentum flux to global values and values in the tropics, an area of prevailing low winds. We found that the spread of results stemming from the choice of drag coefficient parameterization was 14% in the Arctic, the NA and globally, but it was higher (19%) in the tropics. On monthly time scales, the differences were larger at up to 29% in the NA and 36% in the EA (in months of low winds) and even 50% locally (the area west of Spitsbergen). Comparing the values of drag coefficient from chosen parameterizations, it showed that momentum fluxes were largest for all months, in both regions with low and high winds, when the CD values increased linearly with wind speed.
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"Noise" in climatologically driven ocean models with different grid resolution
Oceanologia 2019, 61(3), 300-307
https://doi.org/10.1016/j.oceano.2019.01.001

Shengquan Tang1,2, Hans von Storch1,2,*, Xueen Chen1, Meng Zhang2
1College of Oceanic and Atmospheric Sciences, Ocean University of China, Qingdao, China
2Institute of Coastal Research, Helmholtz-Zentrum Geesthacht, Geesthacht, Germany;
e-mail: hvonstorch@web.de
*corresponding author

keywords: "Noise", Internal variability, South China Sea, Eddies, Model resolution

Received 26 July 2018, Accepted 11 January 2019, Available online 28 January 2019.

Abstract

The internally generated variability in the climate system, which is unrelated to any external factors, can be conceptualized as “noise”. This noise is a constitutive element of high-dimensional nonlinear models of such systems. In a three-layer nested simulation, which is forced by climatological (periodic) atmospheric forcing and includes an (almost) global model, a West-Pacific model, and South China Sea (SCS) model, we demonstrate that such “noise” builds also ocean models. They generate variability by themselves without an external forcing. The “noise” generation intensifies with higher resolution, which favors macroturbulence.
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Seasonal patterns and environmental drivers of nirS- and nirK-encoding denitrifiers in sediments of Daya Bay, China
Oceanologia 2019, 61(3), 308-320
https://doi.org/10.1016/j.oceano.2018.10.001

Rongjun Shi1, Shumin Xu1,2, Zhanhui Qi1,*, Honghui Huang1,*, Qingyang Liang1
1Guangdong Provincial Key Laboratory of Fishery Ecology and Environment and Key Laboratory of Open-Sea Fishery Development, Ministry of Agriculture, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Science, Guangzhou, China;
e-mail: qizhanhui@scsfri.ac.cn, huanghh@scsfri.ac.cn
*corresponding author
2College of Marine Science of Shanghai Ocean University, Shanghai, China

keywords: Abundance, Community structure, nirS-encoding denitrifiers, nirK-encoding denitrifiers, Sediment, Daya Bay

Received 19 September 2018, Accepted 12 January 2019, Available online 28 January 2019.

Abstract

The seasonal patterns of the denitrifiers (denitrifying bacteria) in the sediment of Daya Bay, southern China, were examined using quantitative PCR and high-throughput MiSeq sequencing methods in spring, summer and winter. The abundance and diversity of nirS-encoding denitrifiers were much higher than that of nirK-encoding denitrifiers, indicating that the former probably dominated the denitrification processes in sediments of Daya Bay. The average abundance and diversity of nirS-encoding denitrifiers were much higher in spring than that in summer and winter, on the other hand, the abundance of nirK-encoding denitrifiers showed the opposite pattern. The species composition of nirS-encoding denitrifiers community in spring differed significantly from that in summer and winter, whereas, no significant difference existed between summer and winter. The dominant environmental drivers for the diversity of community species were NO2, NO3 and DO concentrations. The abundances of dominant genera of nirS- encoding denitrifiers, Accumulibacter sp. and Cuprizvidus sp., were significantly higher in summer and winter than that in spring, and were negatively correlated with NO2, NO3, and DO concentrations (p < 0.05). In contrast, the abundances of Azoarcus sp. and Halomonas sp., were highest in spring, and were positively correlated with NO3 and NO2 content (p < 0.05). For nirK-encoding denitrifiers, a significant difference in community composition was observed between spring and winter. No obvious correlation was found between community composition of nirK-encoding denitrifiers and environmental parameters.
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Linking sea level dynamic and exceptional events to large-scale atmospheric circulation variability: A case of the Seine Bay, France
Oceanologia 2019, 61(3), 321-330
https://doi.org/10.1016/j.oceano.2019.01.003

Imen Turki*, Nicolas Massei*, Benoit Laignel*
UContinental and Coastal Morphodynamic Laboratory, Normandy University, Rouen, France;
e-mail: imen.turki@univ-rouen.fr, nicolas.massei@univ-rouen.fr, benoit.laignel@univ-rouen.fr
*corresponding author

keywords: Sea level dynamic, Envelope approach, Demodulated surges, Storm events, Climate patterns

Received 16 September 2018, Accepted 15 January 2019, Available online 1 February 2019.

Abstract

In this study, the multi-time-scale variability of the South English Channel (case of the Seine Bay, North France) sea level and its exceptional events have been investigated in relation with the global climate patterns by the use of wavelet multi-resolution decomposition techniques. The analysis has been focused on surges demodulating by an envelope approach. The low-frequency components of the interannual (2.1-yr, 4-yr, 7.8-yr) and the interdecadal (15.6-yr and 21.2-yr) time-scales, extracted from 46-years demodulated surges, have been correlated to 36 exceptional stormy events according to their intensity. Results have revealed five categories of storms function on their correlation with the interannual and the interdecadal demodulated surges: events with high energy are manifested at the full scales while moderate events are only observed at the interannual scales. The succession of storms is mainly carried by the last positive oscillations of the interannual and the interdecadal scales. A statistical downscaling approach integrating the discrete wavelet multi-resolution analysis for each time-scale has been used to investigate the connection between the local dynamic of surges and the global atmospheric circulation from SLP composites. This relation illustrates dipolar patterns of high-low pressures suggesting positive anomalies at the interdecadal scales of 15.6-yr and 21.3-yr and the interannual scales of 4-yr while negative anomalies at 7.8-yr should be related to a series of physical mechanisms linked to the North-Atlantic and ocean/atmospheric circulation oscillating at the same time-scales. The increasing storm frequency is probably related to the Gulf Stream variation and its weakening trend in the last years.
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Impact of a dipole on the phytoplankton community in a semi-enclosed basin of the southern Gulf of California, Mexico
Oceanologia 2019, 61(3), 331-340
https://doi.org/10.1016/j.oceano.2019.01.004

Elizabeth Durán-Campos1,*, María Adela Monreal-Gómez2, David Alberto Salas de León2, Erik Coria-Monter3
1DGAPA Postdoctoral Fellowship, Institute of Marine Sciences and Limnology (ICML), National Autonomous University of Mexico (UNAM), Mexico City, Mexico;
e-mail: eduran@cmarl.unam.mx
*corresponding author
2Ecology and Aquatic Biodiversity Academic Unit, Institute of Marine Sciences and Limnology (ICML), National Autonomous University of Mexico (UNAM), Mexico City, Mexico
3Cátedras CONACYT, Institute of Marine Sciences and Limnology (ICML), National Autonomous University of Mexico (UNAM), Mexico City,Mexico

keywords: Dipole, Oceanic thermohaline front, Phytoplankton, Chlorophyll-a, Gulf of California, Bay of La Paz

Received 24 August 2018, Accepted 22 January 2019, Available online 2 February 2019.

Abstract

The present study assesses the impact of a dipole on the abundance and distribution of phytoplankton groups as well as the chlorophyll-a concentration in the Bay of La Paz, Gulf of California, Mexico. Based on in situ observations obtained in a multidisciplinary research cruise during the summer of 2008, a mesoscale dipole (cyclone-anticyclone) was observed; the cyclone had ~25 km diameter and tangential speed of ∼45 cm s−1, while the anticyclone had ~15 km diameter and tangential speed of ~40 cm s−1. Strong gradients in conservative temperature and density were observed between both structures, suggesting the presence of an oceanic thermohaline front. Differences in phytoplankton distribution showed minimum abundance of diatoms in the southern bay and close to Roca Partida Island, and maximum in the periphery in the northern cold core. The maximum abundance of dinoflagellates and silicoflagellates occurred at the frontal zone. The chlorophyll-a concentration was high in the region associated with the frontal zone. Although mesoscale eddies are ubiquitous processes in the Bay of La Paz, this study represents the first observational report of the impacts of a dipole on the phytoplankton structure and chlorophyll-a in the region. The observations presented here indicate the existence of a strong association between the mesoscale processes and the phytoplankton community in the study area. This study highlights the value of efforts to improve projections of physical forcing and its influence on the planktonic ecosystem.
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Limited success of the non-indigenous bivalve clam Rangia cuneata in the Lithuanian coastal waters of the Baltic Sea and the Curonian Lagoon
Oceanologia 2019, 61(3), 350-367
https://doi.org/10.1016/j.oceano.2019.01.005

Sabina Solovjova1,2,*, Aurelija Samuilovienė1, Greta Srėbalienė2, Dan Minchin1,3, Sergej Olenin1
1Marine Research Institute, Klaipėda University, Klaipėda, Lithuania;
e-mail: sabina.lt@gmail.com
*corresponding author
2Department of Environmental Research, Environmental Protection Agency, Klaipėda, Lithuania
3Marine Organism Investigations, Ballina, Killaloe, Ireland

keywords: Semitropical bivalve, Coastal lagoon, Exposed coast, Winter conditions, Ballast water, Natural spread.

Received 29 January 2018, Accepted 29 January 2019, Available online 13 February 2019.

Abstract

The gulf wedge clam, common rangia Rangia cuneata, with a native origin in the Gulf of Mexico has spread to north European brackish and freshwaters. This semitropical species is able to survive in conditions of low winter temperatures in boreal environment of the Baltic Sea. Its expansion within lagoons and sheltered bays in the southern and eastern parts of the Baltic Sea appears to be with natural spread and its discontinuous distribution is likely to have been with shipping, either within ballast water or as settled stages transported with dredged material. In this account, we report on the occurrence of R. cuneata in Lithuanian waters. We compare habitats of the common rangia in the Curonian Lagoon and in the exposed coastal waters of the Baltic Sea. We notice high mortality of the species in the Lithuanian waters in comparison to the neighboring Vistula Lagoon. Based on finding of small specimens of R. cuneata attached to the spiked watermilfoil Myriophyllum spicatum, we indicate a risk of local spread with movements of fishing equipment and snagged plants on anchors or boat trailers removed from the water. We discuss the possibility of further spread of the common rangia to similar environments in the Baltic Sea and elsewhere in Europe.
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Laboratory study of suspended sediment dynamics over a mildly sloping sandy seabed
Oceanologia 2019, 61(3), 350-367
https://doi.org/10.1016/j.oceano.2019.01.006

Barbara Stachurska*, Ryszard Staroszczyk
Institute of Hydro-Engineering, Polish Academy of Sciences, Gdańsk, Poland;
e-mail: b.stachurska@ibwpan.gda.pl
*corresponding author

keywords: Sediment dynamics, Sloping seabed, Bed ripples, Wave bottom boundary layer, Particle image velocimetry

Received 9 July 2018, Accepted 29 January 2019, Available online 21 February 2019.

Abstract

This paper presents the results of laboratory measurements of suspended sediment movement induced by regular non-linear water waves propagating over a mildly sloping sandy seabed covered with ripples. The measurements conducted in a water flume were carried out by applying the technique of particle image velocimetry (PIV). The aim of those experiments was to investigate near-bed velocities of sediment particles under controlled surface wave conditions. In particular, horizontal and vertical profiles of sand grain velocities were measured, and some comparisons between the measured and theoretically-predicted quantities were carried out. A number of selected wave cases were examined, for which the Ursell number ranged from 18 to 39, and the sediment grain mobility numbers varied between 12 and 26. For these flow conditions, the near-bed layer of intense sediment grain movements had a thickness of about 2–3 ripple heights. The maximum horizontal sediment velocities measured over ripple crests were about twice as large as those over ripple troughs. Vertical sediment velocities above ripple crests and troughs were similar, amounting to about 1/4 to 1/3 of horizontal velocities over ripple crests. The detailed quantitative results obtained in the flume can help validate other experimental techniques and can be useful in testing numerical models for simulating surface wave-induced sediment dynamics.
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Short-term variation of zooplankton community in Cintra Bay (Northwest Africa)
Oceanologia 2019, 61(3), 368-383
https://doi.org/10.1016/j.oceano.2019.02.001

Amina Berraho*, Hinde Abdelouahab*, Tarik Baibai*, Said Charib*, Aziz Agouzouk*, Ahmed Makaoui*
National Institute of Fisheries Research, Casablanca, Morocco;
e-mail: aminaberraho@gmail.com, hind.abdelouahab@gmail.com, baibaitarik@gmail.com, saidcharib@gmail.com, larissijamila@gmail.com, larissijamila@gmail.com,
*corresponding author

keywords: Cintra Bay, Zooplankton, Copepods, Diversity indices, Environmental parameters

Received 19 October 2018, Accepted 14 February 2019, Available online 27 February 2019.

Abstract

This is the first study that describes the spatial-temporal distributions of the zooplankton community and potential control factors in Cintra Bay. Zooplankton were sampled using a bongo net, 150 μm mesh size, during two surveys, in autumn 2015 and spring 2016, extending from the coast to the open sea. Fourteen zooplankton groups were identified, where copepods represented 49.1% and 92.5% of the total abundance in autumn 2015 and spring 2016, respectively. Tintinnids accounted for 39.7% and 4.7%, respectively. The total zooplankton abundance was higher in autumn (55 992 ind m−3) than in spring (2123 ind m−3). Nineteen species of copepods, belonging to 14 families, were identified. Euterpina acutifrons and Oithona nana were the most common and abundant species. The Acartiids were represented by three species (Acartia clausi, A. tonsa and A. bifilosa) in autumn and one species in spring (A. clausi). The copepods diversity was significantly different between the two seasons showing high values at the entrance and the center of the bay in autumn 2015 and in the southern half of the bay in spring 2016. The copepod structure was characterized by 13 species at different degrees of contribution in autumn 2015. In spring 2016, only four species qualified as indicator species although their contribution was not significant. Given its large opening on the ocean, Cintra Bay benefits largely from the conditions of the oceanic environment, particularly the upwelling. This situation is likely to have an impact on the spatiotemporal variability of the composition and distribution of zooplankton, especially the copepods.
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Bedload transport in the Vistula River mouth derived from dune migration rates, southern Baltic Sea
Oceanologia 2019, 61(3), 384-394
https://doi.org/10.1016/j.oceano.2019.02.003

Aliaksandr Lisimenka1,2,*, Adam Kubicki3
1Maritime Institute in Gdańsk, Gdańsk, Poland
2Institute of Oceanology, Polish Academy of Sciences, Sopot, Poland;
e-mail: sasha@im.gda.pl
3GEO Ingenieurservice Nord-West, Wilhelmshaven, Germany
*corresponding author

keywords: Sand dune migration, Bedload transport, Vistula River mouth

Received 3 December 2018, Accepted 27 February 2019, Available online 15 March 2019.

Abstract

In this paper, bedload sediment transport to the Baltic Sea in the main Vistula River mouth (Przekop Wisły) is estimated. For the first time in this area, investigations were performed based on the non-invasive measurement techniques with the using of hydroacoustic tools. Repeated bathymetric surveys were carried out using a multibeam echosounder for the period with hydrological conditions close to that of the long-term mean annual water discharge. Quantification of the bedload transport, as a main factor for the subaqueous Vistula delta development, involved applying the bedform tracking technique, and estimating the dune celerity by analysing the cross-correlation functions of bed elevation profiles (BEPs). The BEPs were obtained along two transects of 500 m in length situated in two different morphological parts of the river mouth – in the “shallow” and in the “deep” sites located upstream and downstream of the submerged sandbar, respectively. Contrarily to previous observations, the bedload transport was found to take place constantly. Moreover, a significant difference in a character of dune migration between the two sites of the investigated area was determined. The “shallow” dunes migrate 7 times faster (0.022 m/h) than the “deep” ones (0.003 m/h). Estimation of the daily bedload transport towards the Baltic Sea revealed values about 40.9 t/day and 8.4 t/day for “shallow” and “deep” sites, respectively. This result can probably indicate that a significant portion of sediments (ca. 80%) transported by the river during average hydrological conditions is deposited temporarily on the submerged sandbar, causing its growth.
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First new record of two diatoms (Caloneis africana (Giffen) Stidolph and Luticola nivalis (Ehrenberg) D. G. Mann) from South West Coast of India (Cochin backwaters)
Oceanologia 2019, 61(3), 395-399
https://doi.org/10.1016/j.oceano.2018.12.002

Geo Joseph*, Mannancheril Sebastian Francis
Sacred Heart College, Mahatma Gandhi University, Kerala, India;
e-mail: geojoseph7777@gmail.com
*corresponding author

keywords: South West Coast of India, Diatoms, Caloneis africana, Luticola nivalis

Received 23 October 2018, Accepted 14 December 2018, Available online 28 December 2018.

Abstract

The main objective of this paper is to report two diatoms (Caloneis africana (Giffen) Stidolph and Luticola nivalis (Ehrenberg) D. G. Mann) from Cochin backwaters, which prove to be a new finding from Indian waters. Surface water samples were collected monthly from twelve stations covering the ecosystem from May 2015 to April 2016. The analysis of physicochemical parameters and the preparation of permanent slides of diatoms were performed based on standard procedures. Descriptions, world distribution and photographs of the two diatoms are included in this paper. These two new species further enrich the diatom floristic diversity of Cochin backwaters in India.
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