Institute of Oceanology, Polish Academy of Sciences, Powstancow Warszawy 55, 81–712 Sopot, Poland; abesz@iopan.gda.pl
Keywords: Pomeranian Bay, River Odra, riverine water transport circulation, river plume
Manuscript received 30 March 1999, reviewed 20 April 1999, accepted 2 June 1999.Abstract
During several cruises of r/v 'Oceania' in different seasons of 1993-1997 detailed investigations of the Pomeranian Bay were carried out with particular attention to the vicinity of the Odra river mouth. On the basis of CTD soundings as well as quasi-continuous profiling by means of a towed CTD probe, the thermohaline fields were analysed in order to determine the pattern of riverine water transport. The characteristic flow paths under different meteorological conditions were identified, Ekman transport of freshened waters being found to prevail along the coasts of the Pomeranian Bay. Physical phenomena such as the pulsating outflow of the river Odra and the formation of isolated plumes of freshened water were observed. The vertical and horizontal extents as well as the lifetime and speed of movement of the plume-like structures were estimated. A typical plume was a few km in diameter and there were steep horizontal and vertical salinity gradients at the boundaries. As the plume moved away from the mouth, it was transformed and finally vanished. There was strong wind mixing and entrainment into underlying, more saline water at some distance from the channel mouth. Hydrological fronts between riverine and ambient waters frequently formed. Numerous intrusions were found in the temperature and salinity profiles in the frontal zones. The freshwater fraction in the entire volume of the bay waters was estimated for different hydrological situations, the highest values being obtained for the period following the flood event of summer 1997. Under favourable wind conditions, dense, saline waters flowing in from the Arkona and Bornholm Deeps were present in the near-bottom layer at the edges of the bay. Anomalously, waters of higher salinity were found in the Pomeranian Bay in November 1997 as a result of a minor inflow from the Danish Straits.
Seasonal changes in selected optical parameters
in the Pomeranian Bay in 1996-1997
Oceanologia 1999, no 41 (3), pp. 309-334
Piotr Kowalczuk, Slawomir Sagan, Jerzy Olszewski, Miroslaw Darecki, Ryszard Hapter
Institute of Oceanology, Polish Academy of Sciences, Powstancow Warszawy 55, 81-712 Sopot, Poland;
piotr@iopan.gda.pl
Keywords: optical properties, seasonal changes, Pomeranian Bay
Manuscript received 12 April 1999, reviewed 24 May 1999, accepted 16 June 1999.
Abstract
The main task of the Joint Polish-German Pomeranian Bay Project was to achieve a better understanding of the impact of freshwater discharge on this environment. The freshwater from the River Odra enters the Pomeranian Bay through four outlets. The most important of these is the River Swina, as it carries the largest volume of water exchange between the bay and the Szczecin Lagoon. This freshwater carries a large load of optically active substances: dissolved organic materials, mineral and organic sediments, as well as nutrients, which boost phytoplankton growth. The effect of riverine discharge can be traced with the use of optical methods. The elevated level of optically active components can significantly reduce the light required for photosynthesis. The Institute of Oceanology carried out a survey of selected inherent and apparent optical properties in the Pomeranian Bay in three seasons in 1996 and 1997. The results are presented and discussed, as are the relations between the various optical parameters and salinity.
Near-bottom fluxes and composition of suspended matter in the Pomeranian Bay
Mario Jose Laima
Lars Chresten Lund-Hansen
Ksenia Pazdro
Christian Christiansen
Kay-Christian Emeis
Keywords: suspended matter, sedimentation fluxes, organic matter, fatty acids, River Odra
Manuscript received 19 January 1999, reviewed 23 February 1999, accepted 26 March 1999.
The quality and composition of suspended organic matter in
near-bottom fluxes was determined at a
mooring station (Odas Tonne) 20 km north-north-west
of the Odra river mouth from June to December
1997. Salinity data and high concentrations of suspended
matter near the bottom showed that the
material entering the Pomeranian Bay from the Odra flood
was recognisable for about three weeks.
Vertical sediment fluxes, however, were low
~ 40 g m-2 d-1
compared to those measured later in the year
~ 60 g m-2 d-1. On the other hand,
average molar CNP ratios in sediment trap material decreased from
June to December 1997. These results may have been a combined effect
of dilution and material
transport in a layer close to the sediment surface.
Fluff layers sampled at Odas Tonne in August 1997
contained a very high proportion of branched fatty acids
of bacterial origin, indicating high rates of
bacterial degradation. Long-chain fatty acids indicated an
origin from higher terrestrial plants. The
saturated fatty acid content was high in the surface
sediment and the traps, increasing towards the top
trap. The percentage composition of fatty acids indicated
that the lowest trap was fed mainly by material
from the underlying sediment. Low salinities, variability
in molar ratios for major elements, higher than
usual bacterial activities and detection of fatty
acids characteristic of land plants during the June-August
deployment show a relationship with the Odra flood
of summer 1997.
Henryk Renk, Stanislaw Ochocki, Henryk Chmielowski,
Slawomira Gromisz, Jan Nakonieczny, Marianna Pastuszak, Mariusz Zalewski
Keywords: photosynthetic rate, assimilation number, photosynthetic light curves, Pomeranian Bay
Manuscript received 18 January 1999, reviewed 8 March 1999, accepted 8 April 1999.
Photosynthetic light curves at selected stations in the
Pomeranian Bay were determined during four cruises undertaken
in March and July 1996, and in May and October 1997. The mean
assimilation numbers measured in particular seasons were as
follows: spring - 2.46 mgC mgChl-1 h-1,
summer - 3.99 mgC mgChl-1 h-1,
autumn - 3.24 mgC mgChl-1 h-1 and
winter - 2.17 mgC mgChl-1 h-1. A significant correlation
was found between the assimilation number and water temperature
over the entire period of study. In some seasons a dependence
between the assimilation number and nutrient concentrations was
also noted. Assimilation numbers in the areas adjacent to the Odra
river months were higher than in the offshore zone.
Stanislaw Ochocki, Henryk Chmielowski, Jan Nakonieczny, Mariusz Zalewski
Keywords: primary production, chlorophyll a, Pomeranian Bay
Manuscript received 10 May 1999, reviewed 7 June 1999, accepted 15 June 1999.
Primary production and chlorophyll a concentrations were
measured in March and May 1996, July and October 1997. The
study was carried out in the coastal zone adjacent to the
mouths of the Swina and Dziwna, which together drain over 80%
of the waters carried by the river Odra, and in the open
Pomeranian Bay.
Anetta Ameryk, Zbigniew Mudryk, Beata Podgorska
Keywords: Pomeranian Bay, bacterioplankton, abundance, biomass, production
Manuscript received 18 January 1999, reviewed 22 February 1999, accepted 17 March 1999.
A microbiological investigation was carried out in the
Pomeranian Bay in 1996-1997 to determine the spatial and
seasonal changes in the numbers, biomass and productivity of
bacterioplankton. Substantial differences in the spatial
distribution of bacterioplankton populations were found. At the
stations in the coastal zone of the Pomeranian Bay numbers,
biomass and production of bacteria were high, with maximum
values noted at the mouth of the river Swina. This is
indicative of the significant impact of riverine waters on the
bacterioplankton in the Pomeranian Bay.
Slawomira Gromisz, Zbigniew Witek, Tomasz Mackiewicz
Keywords: phytoplankton, Baltic Sea, estuary, assemblages, diversity
Manuscript received 30 April 1999, reviewed 14 June 1999, accepted 6 July 1999.
The article is based on the analysis of phytoplankton samples
collected in the Pomeranian Bay during five cruises in the years 1993,
1996 and 1997.
Leszek Frankowski, Jerzy Bolalek
Keywords: organic matter deposition and transformations,
phosphorus release, sediments, principal component analysis, Pomeranian Bay
Manuscript received 19 February 1999, reviewed 23 March 1999, accepted 9 June 1999.
A laboratory chamber experiment was carried out to
estimate the release of phosphate from sediments to water. The
phosphate thus released originated almost exclusively from the
mineralisation of organic matter. Since the release took place
between the fifth and the tenth day of the experiment, the
compounds undergoing mineralisation were most probably
proteins, aminoacids or lipids, whose decomposition times are
of the order of several days to several weeks.
Dorota Burska, Leszek Frankowski, Jerzy Bolalek
Keywords: Pomeranian Bay, sediments, organic carbon, organic nitrogen,
C/N ratio, total phosphorus, organic phosphorus
Manuscript received 4 March 1999, reviewed 9 April 1999, accepted 15 June 1999.
Seasonal changes in the chemical composition of sediments from four
stations located in the Pomeranian Bay were analysed. The investigations
were carried out in four periods (March and July 1996, and May and October
1997). The following parameters were investigated: organic carbon and
nitrogen, total phosphorus and organic phosphorus, loss on ignition and
redox potential.
Jerzy Olszewski, Piotr Kowalczuk, Miroslaw Darecki
Keywords: marine optics, remote sensing, local algorithms
Manuscript received 12 March 1999, reviewed 12 May 1999, accepted 24 May 1999.
In-water remote sensing algorithms for
estimating chlorophyll concentration and the absorption
of light (400 nm) by yellow substances valid for the
surface layer of the Pomeranian Bay are described. The
accuracy of the algorithms has been estimated at 20-60%.
The statistical analysis of data
collected during a two-year experiment in 1996-1997 enable
algorithms to be constructed which use a linear
combination of spectral reflectances at selected
wavelengths, all of them in the log-log form. The
wavelengths in nm are 510, 550, 589 or 510, 625 in the
'chlorophyll' case, and 589, 665 or 490, 665 in the
'yellow substances' case. The correlation coefficient
between the log-transformed reflectance ratios and the
chlorophyll concentration is around 0.9. The correlation
coefficient between the log-transformed
reflectance ratios and the yellow substance absorption
coefficient at
Jaroslaw Tegowski, Zygmunt Klusek
Keywords: marine acoustics, bottom backscattering, Baltic Sea
Manuscript received 17 March 1999, reviewed 12 May 1999, accepted 30 June 1999.
The properties of bottom backscattered signals in the
Pomeranian Bay have been investigated using a one-frequency
single beam echosounder working at a central frequency of 30 kHz.
The backscattering strength, time of reverberation and
attenuation coefficient in sediments were estimated and mapped
for the whole area. The other purpose of the investigations was
to verify the acoustic one-frequency multiparametric method in order
to determine the sediment-type distribution in the Pomeranian Bay.
This method was found as useful tool for sediment identification
in the study area.
Oceanologia 1999, no 41 (3), pp. 335–353
Department of Earth Sciences, Aarhus University, Ny Munkegade, Building 520, 8000 Aarhus C, Denmark;
geomario@aau.dk
Marine Ecology, Biological Institute, Aarhus University, Finlandsgade 14, 8200 Aarhus N, Denmark;
Institute of Oceanology, Polish Academy of Sciences, Powstancow Warszawy 55, 81-712 Sopot, Poland;
Institute of Geography, University of Copenhagen, Øster Voldgade 10, 1350 Copenhagen K, Denmark;
Baltic Sea Research Institute Warnemünde, Seestrasse 15, 18111 Warnemünde, Germany.
Abstract
Photosynthetic light curves in the Pomeranian Bay
Oceanologia 1999, no 41 (3), pp. 355-371
Department of Oceanography, Sea Fisheries Institute, H.Kollataja 1, 81-332 Gdynia, Poland;
sochocki@miryb.gdynia.pl
Abstract
The impact of Odra river waters on the seasonal and spatial
distribution of primary production and chlorophyll a
concentrations in the Pomeranian Bay in 1996-1997
Oceanologia 1999, no 41 (3), pp. 373-388
Department of Oceanography, Sea Fisheries Institute H. Kollataja 1, 81-332 Gdynia, Poland;
sochocki@miryb.gdynia.pl
Abstract
Chlorophyll a concentrations in the entire Pomeranian Bay
varied between 0.8 and 16.5 mg m-3. The minimal daily in situ
primary production measured in March was 19.3 mgC m-2 d-1,
the July maximum was 1238.6 mgC m-2 d-1.
The potential primary production ranged from 1.5 to 59.2 mgC m-3 h-1.
The rate of photosynthesis expressed as the assimilation number (AN) varied
from 0.3 to 6.6 mgC mgchl-1 h-1.
The waters of the river Odra reinforce eutrophication in the coastal zone of the Pomeranian Bay.
The photosynthetic rate there is usually higher than in open bay waters.
The abundance, biomass and production of bacterioplankton in the Pomeranian Bay
Oceanologia 1999, no 41 (3), pp. 389-401
Marine Biology Centre, Polish Academy of Sciences, Sw. Wojciecha 5, 81-347 Gdynia, Poland;
ameryk@cbmpan.gdynia.pl
Abstract
Seasonal fluctuations and bacterial microflora activity were
recorded. The dynamics of the changes showed that most of the
bacteriological parameters examined reached their maximum in
summer while minimum values were noted in winter.
The impact of the River Odra on the phytoplankton composition and biomass in the Pomeranian Bay
Oceanologia 1999, no 41 (3), pp. 403-427
Department of Oceanography, Sea Fisheries Institute, H. Kollataja 1, 81-332 Gdynia, Poland;
grosz@miryb.gdynia.pl
Abstract
In each season a number of phytoplankton assemblages were formed
under the impact of the hydrological and hydrochemical conditions
gradually changing along an axis from the outlets of the Szczecin
Lagoon towards the open sea. The most distinct assemblages could be
described as 'river-mouth', 'open-Bay' and 'open-sea' assemblages.
The highest phytoplankton biomass was noted near the mouth of the
Swina Strait in the 'river-mouth' assemblages, where the concentration
of chlorophyll a was 4 to 5 five times higher in comparison
with the 'open-sea' values. The phytoplankton biomass in the 'open-Bay'
assemblages was roughly twice as high as that in the 'open-sea' assemblages.
Because of the high N:P ratio in the Odra waters, phosphorus was
very probably the factor limiting phytoplankton primary production in
the Pomeranian Bay during periods of intensified inflow of riverine waters.
The species dominating the phytoplankton of the Pomeranian Bay
during the present study were found to be the same as those recorded
in this region 40 years earlier.
Transformations and release of phosphorus forms at the sediment-water interface in the Pomeranian Bay
(southern Baltic)
Oceanologia 1999, no 41 (3), pp. 429-444
Institute of Oceanography, Gdansk University, al. Marsz. Pilsudskiego 46, 81-378 Gdynia, Poland;
frank@pasat.ocean.univ.gda.pl
Abstract
Principal component analysis (PCA) was applied to
determine the similarities and differences in the chemical
composition of the surface sediments of the Pomeranian Bay.
The study area can be divided into three subregions based on
PCA. The first is the estuarine region A with a distinct
station located next to the Swina River estuary; the second is
the central Pomeranian Bay (region B), and the third is the
deep region C, with a distinct subregion in the vicinity of
the Sassnitz Deep.
The phosphorus flux from sediments to water was estimated
at 14 x 103 t per year, but was balanced by the deposition
flux of organic matter. Phosphorus deposition and release at
the sediment-water interface in the Pomeranian Bay therefore
play a crucial role in qualitative transformations of the
phosphorus compounds, although Pomeranian Bay sediments may
not be important as a source or sink of phosphorus compounds.
Temporal variability in the chemical composition of bottom sediments in the Pomeranian Bay (southern Baltic)
Oceanologia 1999, no 41 (3), pp. 445-459
Institute of Oceanography, Gdansk University, al. Marsz. Pilsudskiego 46, 81-378 Gdynia, Poland;
burak@pasat.ocean.univ.gda.pl
Abstract
On the basis of these results the influence of the following
processes and phenomena was noted: the early spring phytoplankton bloom
dominated by diatoms (March 1996); the intense inflow of allochthonous
matter brought into the Bay with the waters of the Swina (May 1997); the
summer bloom of blue-green algae and dinoflagellates (July 1996); the
consequences of the summer 1997 flood which occurred in southern Poland
(October 1997).
In-water remote sensing algorithms for the detection of chlorophyll and yellow substances in the Pomeranian Bay
Oceanologia 1999, no 41 (3), pp. 461-474
Institute of Oceanology, Polish Academy of Sciences, Powstancow Warszawy 55, 81-712 Sopot, Poland;
olszewsk@iopan.gda.pl
Abstract
= 400 nm is around 0.6.
Acoustic properties of the Pomeranian Bay bottom sediments
Oceanologia 1999, no 41 (3), pp. 475-487
Institute of Oceanology, Polish Academy of Sciences, Powstancow Warszawy 55, 81-712 Sopot, Poland;
tegowski@iopan.gda.pl
Abstract