Oceanologia No. 47 (2) / 05

Contents

Papers

Communications

Papers


Coherent current oscillations and water exchange in the straits of the Gulf of Riga
Oceanologia 2005, 47(2), 115-127

Lembit Talpsepp
Marine Systems Institute, Department of Marine Physics, Tallinn University of Technology
Akadeemia tee 21, EE-12618 Tallinn, Estonia;
e-mail: talpsepp@phys.sea.ee

Keywords: Gulf of Riga, currents, current oscillations, water exchange, coherent currents

Received 22 December 2004, revised 3 June 2005, accepted 7 June 2005.

This paper was partly supported by Estonian Science Foundation Grant No 5869.
Abstract
The water exchange processes through the Irbe and Virtsu (Suur) Straits were investigated in 1993-1997 within the framework of a five-year study programme - the Gulf of Riga Project. Simultaneous current measurement data from autonomous mooring stations in both straits were available for the analysis in two periods. In addition to the dominant signals - inertial oscillations in the Virtsu Strait and diurnal oscillations in the Irbe Strait - low-frequency oscillations were found in both straits.
    During the experiment in July-August 1994, 12-14-day oscillations were observed in both straits: the maximum phase lag in the Virtsu Strait was 1 day. The other important low-frequency periodic component in both straits was 88 hours. In this case, the phase lag in the Virtsu Strait was about 20 hours.
    In the 1995 experiment in the Irbe Strait, 42-hour oscillations were observed with a phase lag of 10-12 hours. The amplitude was about 30 cm -1 in both straits. As in Lilover et al. (1998), where the flow regime in the Irbe Strait was observed, we can interpret these oscillations as being wind-generated. The present work shows the existence of these disturbances also in the Virtsu Strait.
    The 88-hour oscillations observed in July-August 1994 can be interpreted as the first mode of the basin's eigenoscillations according to the concept of Otsmann et al. (1997) of a basin with two separate outlets. The lowest frequency oscillation with the period of 12-14 days seemed to propagate to the Gulf of Riga from the Baltic Proper, but the generating force could not be established because there was no noticeable variability between depressions and anticyclones during that period.
    Based on the current measurements, two types of water exchange through the Irbe strait were established: the outflow over the whole cross-section of the strait, and a bidirectional flow with an inflow near the southern shore and increasing inflow in the near-bottom layers and an outflow in the northern part of the strait.
full, complete article (PDF - compatibile with Acrobat 3.0), 162 KB

Modelling the light absorption properties of particulate matter forming organic particles suspended in seawater.
Part 1. Model description, classification of organic particles, and example spectra of the light absorption coefficient and the imaginary part of the refractive index of particulate matter for phytoplankton cells and phytoplankton-like particles
Oceanologia 2005, 47(2), 129-164

Bogdan Woźniak1,2*, Sławomir B. Woźniak1,3, Katarzyna Tyszka1, Jerzy Dera1
1 Institute of Oceanology, Polish Academy of Sciences,
Powstańców Warszawy 55, PL-81-712 Sopot, Poland;
e-mail: wozniak@iopan.gda.pl
* corresponding author
2 Institute of Physics, Pomeranian Pedagogical Academy in Słupsk,
Arciszewskiego 22 B, PL-76-200 Słupsk, Poland
3 Marine Physical Laboratory, Scripps Institution of Oceanography,
University of California at San Diego,
La Jolla, 92093-0238 California, USA

Keywords: suspended particulate organic matter, organic particles, light absorption coefficient, imaginary part of the refractive index of light

Received 23 May 2005, revised 6 June 2005, accepted 10 June 2005.

This work was carried out within the framework of IO PAS's statutory research,and also as part of project PZB-KBN 056/P04/2001/3 of the Institute of Physics, Pomeranian Pedagogical Academy in Słupsk.
Abstract
Data on organic substances in the sea are applied to distinguish hypothetical chemical classes and physical types of suspended particulate organic matter (POM) in seawater. Spectra of the light absorption coefficients of particulate matter apm(λ) and the imaginary refractive index n'p(λ), are assessed for some of these classes and types of POM in seawater, that is, for live phytoplankton cells and phytoplankton-like particles. The spectral characteristics of these coefficients are established and the probable ranges of variability of their absolute magnitudes defined on the basis of the mass-specific coefficients of light absorption by the various organic substances forming the particles. Also presented are mathematical relationships linking the coefficients apm(λ) and n'p(λ) for the various chemical classes of POM with their physical parameters, such as the relative contents of organic matter, water, air or some other gas. This article is part of a bio-optical study undertaken by the authors, the objective of which is to implement remote sensing techniques in the investigation of Baltic ecosystems (Woźniak et al. 2004).
full, complete article (PDF - compatibile with Acrobat 3.0), 547 KB

 Fine organic particles in a sandy beach system (Puck Bay, Baltic Sea)
Oceanologia 2005, 47(2), 165-180

Lech Kotwicki, Jan Marcin Węsławski, Anna Szałtynis, Anna Stasiak, Agnieszka Kupiec
Institute of Oceanology, Polish Academy of Sciences,
Powstańców Warszawy 55, PL-81-712 Sopot, Poland;
e-mail: lechk@iopan.gda.pl

Keywords: detritus, sandy beach system, energy flow, filtration, suspension, coastal waters, C/N ratio

Received 19 January 2005, revised 1 April 2005, accepted 11 April 2005.

This research was funded by the LITUS (International Biodiversity Observation Year project) and COSA projects (5th FP of the EU,and SPB COSA of Polish KBN).
Abstract
A total of over 550 samples of particulate organic matter (POM) were obtained from swash and groundwater samples taken on a monthly basis from seven localities on the sandy shores of Puck Bay in 2002 and 2003. Sandy sediment cores from the swash zone were collected to assess the amount of POM in the pore waters. The mean annual concentrations of POM varied between localities from 20 to 500 mg in groundwater and from 6 to 200 mg dm-3 in swash water. The carbon/nitrogen (C/N) ratio in suspended matter was always higher in groundwater (annual mean 12) than in swash water (annual mean 7). The C/N ratio indicates a local, algal origin of POM in the shallow coastal zone.
full, complete article (PDF - compatibile with Acrobat 3.0), 156 KB

 Deposition of large organic particles (macrodetritus) in a sandy beach system (Puck Bay, Baltic Sea)
Oceanologia 2005, 47(2), 181-199

Lech Kotwicki, Jan Marcin Węsławski, Anna Szałtynis, Aleksandra Raczyńska, Agnieszka Kupiec
Institute of Oceanology, Polish Academy of Sciences,
Powstańców Warszawy 55, PL-81-712 Sopot, Poland;
e-mail: lechk@iopan.gda.pl

Keywords: macrodetritus, algal mats, sandy beach system, energy flow, filtration, suspensions, organic carbon, C/N contents

Received 21 February 2005, revised 24 May 2005, accepted 30 May 2005.

Part of this study was supported by the State Committee for Research supporting grant SPB for EU VI FP COSA (Coastal Sands as biocatalytic filters).
Abstract
The aim of this study was to evaluate the amount of organic macrodetritus deposited on the sandy shores of the southern Baltic, and to determine the type of washout material and their chemical composition (carbon and nitrogen).
    Over 900 samples of macrodetritus (particles retained on a 0.5 mm sieve) were collected from seven sampling locations along a 120 km stretch of coastline in Poland at monthly intervals in 2002. Analysis of the C and N content of several categories of detritus supplied information about seasonal changes in and the ageing of algal debris, and indicated that the amount of carrion is constant; the latter is apparently always metabolised very rapidly. The annual deposition of macroalgal detritus on this coast was estimated at 15 000 tonnes fresh weight, that is around 75% of the primary production of filamentous macroalgae in Puck Bay.
    In comparison with the amounts of kelp deposited on sandy beaches in South Africa (Griffiths & Stenton-Dozey 1981), the massive seaweed washouts on Mediterranean beaches (Morand & Briand 1996), or the deposition of algal mats in the northern Baltic (Norkko & Bonsdorff 1996a), the quantities of macrodetritus on the shore in the study area are average, even allowing for the fact that the Baltic Sea is highly eutrophic (HELCOM 2005).
full, complete article (PDF - compatibile with Acrobat 3.0), 191 KB

 Stratification of particulate organic carbon and nitrogen in the Gdańsk Deep (southern Baltic Sea)
Oceanologia 2005, 47(2), 201-217

Dorota Burska, Dorota Pryputniewicz, Lucyna Falkowska
Institute of Oceanography,
University of Gdańsk,
al. Marszałka Piłsudskiego 46, PL-81-378 Gdynia, Poland;
e-mail: burak@sat.ocean.univ.gda.pl

Keywords: POC, PON, thermohaline stratification, fluxes, Gdańsk Deep

Received 2 March 2005, revised 27 April 2005, accepted 16 May 2005.
Abstract
Particulate organic carbon (POC) and nitrogen (PON) concentrations and fluxes were measured during an experiment in the Gdańsk Deep in late spring (30.05.-06.06.2001). The vertical POC and PON concentration profiles were characterised by the highest values in the euphotic layer, a gradual decrease with depth, and an increase below the halocline. The hydrophysical conditions had a decisive impact on POC and PON fluxes in the water column.
    Preferential removal of nitrogen from suspended mater was observed in the entire water column (maximum - in the vicinity of thermocline). There were also differences in the diurnal effectiveness of nitrogen removal as compared to carbon removal. The removal rate was highest at night.
full, complete article (PDF - compatibile with Acrobat 3.0), 414 KB

Faunistic diversity of Maltese pocket sandy and shingle beaches: are these of conservation value?
Oceanologia 2005, 47(2), 219-241

Marika J. Gauci, Alan Deidun, Patrick J. Schembri
Department of Biology,
University of Malta,
Msida MSD06, Malta;
e-mail: asmgauci@maltanet.net

Keywords: shingle, sandy beaches, fauna, coastal conservation, Malta

Received 19 January 2005, revised 21 April 2005, accepted 10 May 2005.

The work on sandy beaches was carried out as part of the MECO project (Bases for the Integrated Sustainable Management of Mediterranean Sensitive Coastal Ecosystems) funded by the European Commission under its "Co-operation with the Third Mediterranean Countries and International Organizations" (Contract No ERBIC 18-C198-0270).
Abstract
The littoral fauna of Maltese sandy and shingle beaches is generally regarded as impoverished and consequently of little conservation interest. The fauna of three sandy and three shingle beaches was systematically sampled by coring, standardised searching and pitfall traps. Diversity and population density were highest at the surface for sandy beaches, but were highest below the surface for shingle. The two beach types had distinct suites of species and individual beaches were faunistically distinct. Maltese sandy and shingle beaches are of conservation importance for their habitat-restricted species, some of which have limited local and regional distributions, and are internationally protected.
full, complete article (PDF - compatibile with Acrobat 3.0), 215 KB

Diurnal variations in nitrogen, phosphorus and iron compounds in the southern Baltic Sea
Oceanologia 2005, 47(2), 243-263

Gabriela Sikorowicz, Lucyna Falkowska, Dorota Burska, Dominika Dunajska, Dorota Pryputniewicz, Rafał Magulski, Anita Lewandowska
Institute of Oceanography,
University of Gdańsk,
al. Marszałka Piłsudskiego 46, PL-81-378 Gdynia, Poland;
e-mail: gabi@sat.ocean.univ.gda.pl

Keywords: nutrients, iron, oxygen conditions, density stratification, Gdańsk Deep

Received 5 July 2004, revised 18 March 2005, accepted 1 April 2005.
Abstract
In order to assess their short-term variability, nutrient concentrations were measured at standard depths at 2 h intervals in the deepest region of the Gdańsk Deep during the first ten days of June 2001. The mean concentrations of nutrients in the euphotic zone were: NN (NO2-, NO3-, NH4+) - 1.93 µmol dm-3, PO43- - 0.12 µmol dm-3 and Fetot - 0.11 µmol dm-3. During daylight hours, when the rate of assimilation was fastest, concentrations of nitrogen, phosphorus and iron compounds were very low. The phosphate concentration fell to a minimum (0.03 µmol dm-3) between 04:00 and 10:00 hrs, while total iron dropped to 0.01 µmol dm-3 between 10:00 and 16:00 hrs. Both levels were below the limiting values for phosphorus and iron. At night, concentrations of NO3- and PO43- rose by 25%, those of NH4+ and Fetot by 35%. The mean molar ratios of NN:PO43- and Fetot:PO43- in the surface layer were subject to significant daily fluctuations. The molar NN:PO43- ratio was higher than the optimum value established for the Baltic Sea. Below the halocline, the concentrations of dissolved iron and phosphorus rose as a result of diffusion from sediments in response to changing redox conditions.
full, complete article (PDF - compatibile with Acrobat 3.0), 552 KB

Zonation of macrofauna across sandy beaches and surf zones along the Dutch coast
Oceanologia 2005, 47(2), 265-282

Gerard Janssen, Saskia Mulder
National Institute for Coastal and Marine Management,
Ministry of Transport, Public Works and Water Management,
Kerklaan 30, 9750 AE Haren, The Netherlands;
e-mail: g.m.janssen@rikz.rws.minven.nl

Keywords: macrobenthos, beach, surf zone, sandy shore, zonation

Received 10 January 2005, revised 27 April 2005, accepted 9 May 2005.

This study was funded by the Dutch Directorate-General of Public Works and Water Management.
Abstract
On nine beaches and two transects in the surf zone along the Dutch coast the presence of benthic macrofauna was studied in relation to basic abiotic characteristics. According to Short's classification system, Dutch beaches are mesotidal and dissipative (Ω = 8.6), and the RTR is low (1.52-1.27), which means that they are not tide-dominated. BSI ranged from 1.4 to 1.1 for the northern and western Dutch coasts respectively and had an overall value of 1.2. The rates of exposure of the beaches varied between 8 and 12, and are therefore regarded as sheltered to moderately exposed. The Dutch beaches display a geographical trend in beach types. Those of the Wadden Sea islands in the northern part of the Netherlands are dissipative, flat, fine-grained, and host high densities of many species of benthic macrofauna. The beaches along the western Dutch coast are less dissipative, steeper, with a higher mean grain size; the species diversity and abundance there are lower. Species diversity and abundance on the beaches increase from the high- to the low-water line. The maximum number of species was found between 0 and -1 m relative to the mean tidal level. The abundance peaks just above the mean tidal level, while the biomass reaches a maximum at the mean tidal level.
    Species diversity and abundance are low in the surf zone, but increase towards deeper water. Species numbers are high and the abundance is very high in the trough between the two bars.
    The relation between the diversity and abundance of macrobenthic species on the one hand, and the sediment composition, water column depth, and position between the bars on the other show a clear pattern of zonation for the beach, surf zone and near-shore: (1) a supralittoral zone with insects and air-breathing crustaceans, (2) a midshore zone, with intertidal species, (3) a lower shore zone, whose species extend into the shallow surf zone, and (4) a zone of sublittoral fauna in the trough between the two breaker bars within the surf zone.
full, complete article (PDF - compatibile with Acrobat 3.0), 242 KB

Communications


The first record of parasites in Gammarus tigrinus Sexton, 1939 - a recent newcomer to the Gulf of Gdańsk
Oceanologia 2005, 47(2), 283-287

Leszek Rolbiecki1, Monika Normant2
1Department of Invertebrate Zoology,
University of Gdańsk,
al. Marszałka Piłsudskiego 46, PL-81-378 Gdynia, Poland;
e-mail: rolbieck@sat.ocean.univ.gda.pl
2Department of Experimental Ecology of Marine Organisms,
Institute of Oceanography,
University of Gdańsk,
al. Marszałka Piłsudskiego 46, PL-81-378 Gdynia, Poland;

Keywords: southern Baltic, non-native species, Gammarus tigrinus, Parasitism, Maritrema subdolum

Received 13 May 2005, revised 2 June 2005, accepted 6 June 2005.

The project has been carried out within the framework of the MarBEF Network of Excellence "Marine Biodiversity and Ecosystem Functioning" which is funded in the (European) Community's Sixth Framework Programme (contract No GOCE-CT-2003-505446). This paper is contribution number MPS-05009 of MarBEF.
Abstract
The present paper reports for the first time on the occurrence of the parasite Maritrema subdolum in the amphipod Gammarus tigrinus, a non-native species in the Gulf of Gdańsk.
full, complete article (PDF - compatibile with Acrobat 3.0), 92 KB