Oceanologia No. 48 (2) / 06





Transport and hydraulically-induced recycling of phosphorus in the North Sea-Baltic Sea transition zone
Oceanologia 2006, no 48(2), pp. 175-191

Rikke R. Kepp1, Anke Struve1, Christian Christiansen1*, Lars Chresten Lund-Hansen2, Morten Holtegaard Nielsen3, Torben Vang4
1Institute of Geography, University of Copenhagen,
Øster Voldgade 10, 1350 Copenhagen K., Denmark;
e-mail: cc@geogr.ku.dk
*corresponding author
2Department of Marine Ecology, University of Aarhus,
Finlandsgade 14, 8200 Aarhus N., Denmark
3Institute of Hydrobiology and Fisheries Sciences, University of Hamburg,
Olbersweg 24, 22767 Hamburg, Germany
4Vejle County, Coastal Section,
Damhaven 12, 7100 Vejle, Denmark

Keywords: Phosphorus recycling, hydraulic mixing, Danish Straits

Received 12 July 2005, revised 5 April 2006, accepted 27 April 2006.

The Danish Natural Science Research Council is acknowledged for financing the project (contract No SNF 21-03-0476).
Bottom-mounted acoustic Doppler current profiler measurements indicate that the net transport of water (844 m3 s-1) in the Little Belt makes up only 6% of the total transport between the Baltic Sea and the North Sea. This is a smaller percentage than the 9% commonly found in the literature. Owing to barotropic and tidal currents the gross transport is 5 times larger. The net transport is directed towards the North Sea mainly in the top 32 m of the water column but towards the Baltic Sea it occurs in the lower 5 m of the water column. The resulting transport of phosphorus is strongly affected by vertical mixing in an area of hydraulic control in the narrow part of the Little Belt. Comparisons of phosphorus profiles in stratified waters and in the mixing area indicate a yearly entrainment of 15 tonnes P from the bottom water to the surface layer. This vertical transport of P forms part of an internal loop in the general transport between the Baltic Sea and the North Sea. Compared to the transport observed 15-16 years ago, the present net phosphorus transport of 163 tonnes yr-1 from the Baltic Sea through the Little Belt is substantially lower.
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Multivariate statistical analysis of water quality and phytoplankton characteristics in Daya Bay, China, from 1999 to 2002
Oceanologia 2006, no 48(2), pp. 193-211

You-Shao Wang1,2,*, Zhi-Ping Lou1, Cui-Ci Sun1,2, Mei-Lin Wu1,2, Shu-Hua Han3
1South China Sea Institute of Oceanology, Chinese Academy of Sciences,
Guangzhou 510301, China;
e-mail: yswang@scsio.ac.cn
*corresponding author
2National Field Station of Marine Ecosystem at Daya Bay in Guangdong,
Shenzhen 518121, China
3School of Chemistry and Chemical Engineering,
Shandong University, Jinan 250100, China

Keywords: water quality, phytoplankton, multivariate statistical analysis, Daya Bay (DYB), South China Sea

Received 28 October 2005, revised 24 April 2006, accepted 31 May 2006.

This research was supported by the project of knowledge innovation program of the Chinese Academy of Sciences (No KZCX3-SW-214, No KSCX2-SW-132), the national natural science foundation of Guangdong (No 032622), and the project of knowledge innovation program of the South China Sea Institute of Oceanology (No LYQY200303).
This study analyzed seasonal physicochemical and phytoplankton data collected at 12 marine monitoring stations in Daya Bay from 1999 to 2002. Cluster analysis based on water quality and phytoplankton parameters measured at the 12 stations could be grouped into three clusters: cluster I - stations S1, S2, S7 and S11 in the southern part and the north-eastern part of Daya Bay; cluster II - stations S5, S6, S9, S10 and S12 in the central and north-eastern parts of Daya Bay; cluster III - stations S3, S4 and S8 in the cage culture areas in the south-western part of Daya Bay and in the north-western part of the Bay near Aotou harbor. Bivariate correlations between phytoplankton density and the major physical and nutrient factors were calculated for all stations. Factor analysis shows that there were high positive loadings of pH, TIN and the ratio of TIN to PO4-P in the three clusters, which indicates that all the stations in the three clusters were primarily grouped according to their respective nutrient conditions.
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Preliminary assessment of the eutrophication status of selected areas in the Polish sector of the Baltic Sea according to the EU Water Framework Directive
Oceanologia 2006, no 48(2), pp. 213-236

Elżbieta Łysiak-Pastuszak1, Andrzej Osowiecki2, Magdalena Filipiak1, Anna Olszewska1, Grażyna Sapota1, Jerzy Woroń1, Włodzimierz Krzymiński1
1Institute of Meteorology and Water Management, Maritime Branch,
Waszyngtona 42, PL-81-342 Gdynia, Poland;
e-mail: Elzbieta.Lysiak-Pastuszak@imgw.pl
2Maritime Institute in Gdańsk,
Abrahama 1, PL-80-307 Gdańsk, Poland

Keywords: eutrophication assessment, Water Framework Directive, reference conditions, Baltic Sea

Received 7 October 2005, revised 11 April 2006, accepted 20 April 2006.

The article is a part of the Polish national report to the HELCOM EUTRO Project: "Development of tools for a thematic eutrophication assessment", 2005. Poster presentation at the 5th Baltic Sea Science Congress in Sopot, 20-24 June 2005.
The implementation of the European Union Water Framework Directive required a number of tasks to be fulfilled: classifying the various water bodies into different types, defining reference conditions for each of the types and assessing their ecological quality status - this last is based on biological, hydromorphological and physicochemical quality elements of the ecosystem.
The paper presents an attempt to estimate reference values in selected areas of Polish coastal and transitional waters as well as in an open sea area following WFD principles.
The preliminary eutrophication assessment showed all the assessed areas to be eutrophication problem areas.

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Relationships between water temperature, nutrients and dissolved oxygen in the northern Gulf of Aqaba, Red Sea
Oceanologia 2006, no 48(2), pp. 237-253

Riyad Manasrah*, Mohammed Raheed, Mohammed I. Badran
Marine Science Station, Aqaba, University of Jordan & Yarmouk University,
PO Box 195, 77110 Aqaba, Jordan;
e-mail: r.manasrah@ju.edu.jo
*corresponding author

Keywords: nutrients, temperature, oxygen, stratification, Gulf of Aqaba

Received 20 February 2006, revised 31 March 2006, accepted 7 April 2006.
Five years (1998, 2000-2003) of summer records of temperature, nutrients and dissolved oxygen concentrations in the upper 400 m of the water column of the northern Gulf of Aqaba were employed to produce a simple statistical model of the relationship between temperature versus nitrate, phosphate, silicate and dissolved oxygen concentrations. Temperature profiles in the upper 400 m during summer revealed a clear thermocline in the upper 200 m. This was reflected in nutrient and oxygen concentrations as nitrate, phosphate, and silicate increased from the surface to deep water while dissolved oxygen decreased. The best fit relationship between temperature versus nitrate and phosphate was inverse linear and the best fit correlation between temperature versus silicate and dissolved oxygen was fractional. The observed nutrient concentrations were shaped by a combination of the hydrodynamics and biological factors. Deep winter mixing and high nutrient concentrations dominate during winter. Shortly after the water stratifies in spring, the nutrients are drawn down by phytoplankton during the spring bloom and remain low throughout the rest of the year. The regression equations presented here will be useful in estimating nutrient concentrations from temperature records as long as the annual natural cycle is the main driver of nutrient concentrations and external inputs are insignificant. Deviations from these relationships in the future could provide insight into modifications in the nutrient concentrations probably resulting from new nutrient sources, such as anthropogenic inputs.
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Toxic Nodularia spumigena blooms in the coastal waters of the Gulf of Gdańsk: a ten-year survey
Oceanologia 2006, no 48(2), pp. 255-273

Hanna Mazur-Marzec*, Adam Krężel, Justyna Kobos, Marcin Pliński
Institute of Oceanography, University of Gdańsk,
al. Marszałka Piłsudskiego 46, PL-81-378 Gdynia, Poland;
e-mail: biohm@univ.gda.pl

*corresponding author

Keywords: Nodularia spumigena, nodularin, remote sensing, Gulf of Gdańsk

Received 7 December 2005, revised 19 April 2006, accepted 27 April 2006.

This work was supported by the State Committee for Scientific Research (project No 0366/PO4/2003/25).
This paper was presented at the 5th Baltic Sea Science Congress in Sopot, 20-24 June 2005.
In the Baltic Sea, summer blooms of the filamentous, nitrogen-fixing cyanobacterium Nodularia spumigena are favoured by high P concentrations at low N:P ratios and a salinity range of 5-13 PSU. The blooms are initiated by calm and sunny weather, an elevated surface water temperature and thermal stratification. The mass occurrence of N. spumigena in coastal waters is a matter of special concern, as the cyanobacterium produces nodularin, a potent pentapeptide hepatotoxin. In the Gulf of Gdansk, the large-scale occurrence of N. spumigena was recorded for the first time in 1994. Blooms of a similar intensity occurred in 2001, 2003 and 2004. Nodularin concentrations in freeze-dried bloom samples varied from 0.01 to 4.01 mg g-1 d.w. In the coastal waters of the Gulf of Gdańsk, cell-bound nodularin concentrations in 2004 and 2005 attained maxima of 25852 ± 107 µg dm-3 and 3964 ± 125 µg dm-3, respectively. Microscopic analysis revealed the presence of diverse N. spumigena forms, with the dominance of curved filaments in bloom samples. The results of in situ studies and remote sensing measurements indicate a high frequency and intensity of cyanobacterial blooms in the Gulf of Gdańsk in the last ten years.
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Body weight, condition, and carapace width and length in the Chinese mitten crab (Eriocheir sinensis H. Milne-Edwards, 1853) collected from the Szczecin Lagoon (NW Poland) in spring and autumn 2001
Oceanologia 2006, no 48(2), pp. 275-285

Przemysław Czerniejewski, Wawrzyniec Wawrzyniak
Department of Fisheries Management in Open Waters, Agricultural University of Szczecin,
Królewicza 4, PL-71-550 Szczecin, Poland;
e-mail: zgl@fish.ar.szczecin.pl

Keywords: Chinese mitten crab (Eriocheir sinensis), body weight, Szczecin Lagoon

Received 12 April 2006, revised 19 May 2006, accepted 23 May 2006.
A newcomer to the Baltic Sea, the Chinese mitten crab is especially abundant in the Szczecin Lagoon (NW Poland), where it was first reported in 1927. Body weight, and carapace width and length, were studied in 647 individuals collected with fyke nets in the Szczecin Lagoon from 30 March-18 April 2001 and from 5-21 November 2001. 51.01 of the 543 autumn specimens were males, but only 30.97% of the 113 spring specimens were males. Body weight varied from 45.1 to 306.5 g, carapace length from 41.07 to 81.02 mm and carapace width from 46.68 to 88.85 mm. The autumn crabs were significantly heavier than the spring specimens.
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The beachflea Platorchestia platensis (Krøyer, 1845): a new addition to the Polish fauna (with a key to Baltic talitrid amphipods)
Oceanologia 2006, no 48(2), pp. 287-295

John I. Spicer1, Urszula Janas2
1Marine Biology and Ecology Research Centre, School of Biological Sciences, University of Plymouth,
Plymouth PL4 8AA, UK;
e-mail: J.I.Spicer@plymouth.ac.uk
2Institute of Oceanography, University of Gdańsk,
al. Marszałka Piłsudskiego 46, PL-81-378 Gdynia, Poland

Keywords: Platorchestia platensis, Talitrid amphipod, Southern Baltic

Received 20 December 2005, revised 23 May 2006, accepted 5 June 2006.

This work was funded through European Community project BALTDER under the fifth FP, contract No EVK3-CT-2002-80005 and the Polish Ministry of Scientific Research and Information.
The present paper reports for the first time on the occurrence of Platorchestia platensis (Krøyer, 1845) (Crustacea, Amphipoda) in Puck Bay (southern Baltic, Poland) in May 2005. A key to the Baltic talitrids is given, which can be used to identify males and females of the four species occurring on Polish shores (Talitrus saltator, Talorchestia deshayesii, Orchestia cavimana, Platorchestia platensis) and additionally Orchestia gammarellus, which may yet be found in the Polish coastal zone.
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Spatial variability of recent sedimentation rates in the Eastern Gotland Basin (Baltic Sea)
Oceanologia 2006, no 48(2), pp. 297-317

Sven Hille, Thomas Leipe, Torsten Seifert
Leibniz Institute for Baltic Sea Research Warnemünde (IOW),
Seestrasse 15, D-18119 Rostock-Warnemünde, Germany;
e-mail: sven.hille@io-warnemuende.de

Keywords: Baltic Sea, Gotland Basin, sediment accumulation, hydrography

Received 12 April 2006, revised 19 May 2006, accepted 23 May 2006.
In order to study recent sedimentation rates in the Eastern Gotland Basin, 52 short sediment cores collected from the deepest part (< 150 m) of the Basin in 2003 were investigated. The upper parts of all the cores were distinctly laminated and dark in colour, followed by a homogeneous, greyish lower part. The thickness of the laminated sequences varied from 17 to 300 mm. 210Pb dating analyses of selected cores revealed that the change from non-laminated to laminated sediments happened about 100 years ago, indicating a shift from predominantly oxic bottom water conditions to anoxic conditions. Used as a time marker, this shift in the sediment texture enabled sediment accumulation rates to be estimated for all sediment cores. The observed mean linear sedimentation rate for the whole basin was 0.93 ± 0.67 mm y-1. The respective bulk sediment accumulation rates ranged from 10.5 to 527 g m-2 yr-1 with an average of 129 ± 112 g m-2 yr-1, indicating a high spatial variability of sedimentation rates within the basin. This agrees very well with the long-term sedimentation pattern since the Litorina transgression. The observed pattern clearly reflects the hydrographic conditions at the seafloor as studied by modelled near-bottom current velocities.
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New records of Cercopagis pengoi (Ostroumov 1891) in the southern Baltic
Oceanologia 2006, no 48(2), pp. 319-321

Anna Olszewska
Institute of Meteorology and Water Management, Maritime Branch,
Waszyngtona 42, PL-81-342 Gdynia, Poland;
e-mail: Anna.Olszewska@imgw.pl
present address: aniao@iopan.gda.pl

Keywords: Cercopagis pengoi, new records, Southern Baltic, invasive species

Received 30 January 2006, revised 10 April 2006, accepted 27 April 2006.
New records of Cercopagis pengoi (Cladocera, Crustacea) are reported for the first time from the central and western part of the Polish zone of the Baltic Sea.
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Nanoflagellates in the Gdańsk Basin: coexistence between forms belonging to different trophic types
Oceanologia 2006, no 48(2), pp. 323-330

Krzysztof Rychert
Sea Fisheries Institute,
Kołłątaja 1, PL-81-332 Gdynia, Poland
e-mail: krychert@pap.edu.pl

Keywords: Nanoflagellates, mixotrophs, Gdańsk Basin, Baltic Sea

Received 20 March 2006, revised 28 April 2006, accepted 19 May 2006.
Nanoflagellates are important bacterivores, but their role is often underestimated because forms capable of phagotrophy and containing chlorophyll (mixotrophs) are excluded from analyses. Research conducted in the coastal zone of the Gdańsk Basin (Baltic Sea) revealed seasonal changes in the relationship between the biomasses of small (1-8 µm) nanoflagellates with (NFChl+) and without chlorophyll (NFChl-). Three distinct patterns were distinguished: (i) spring, when the biomass of NFChl+ was lower than that of NFChl-, (ii) summer and autumn, when NFChl+ were dominant (about 90%), and (iii) late autumn and winter, when the prevalence of NFChl+ was lower (71-79\%). Additional studies showed the existence of spatial differences in the composition of the nanoflagellate community. These spatial differences were not shaped by freshwater input. The possible importance of mixotrophic forms in the Gdańsk Basin is discussed.
full, complete article (PDF - compatibile with Acrobat 4.0), 242 KB The PDF document was amended on 2 April 2009 - see figure 2 corrected.