Oceanologia No. 41 (2) / 99

Contents

Papers

Communications

Papers


Seasonal changes of the aerosol optical thickness for the atmosphere over the Baltic Sea - preliminary results
Oceanologia 1999, no 41 (2), pp. 127–145

Jolanta Kuśmierczyk-Michulec
Institute of Oceanology, Polish Academy of Sciences, Powstańców Warszawy 55, 81–712 Sopot, Poland; michulec@iopan.gda.pl

Anna Rozwadowska
Institute of Oceanology, Polish Academy of Sciences, Powstańców Warszawy 55, 81-712 Sopot, Poland

Keywords: aerosol optical thickness, Baltic Sea, seasonal variability

Manuscript received 30 September 1998, reviewed 15 January 1999, accepted 1 February 1999.
Abstract
A statistical analysis of the aerosol optical thickness and the Angstrom parameters derived from measurements of spectral solar radiation at the surface of the southern and western Baltic Sea is presented. The experimental data were collected on cloudless days during over 20 cruises from March to September within a 4-year period (1994-1998). The monthly and seasonal variability of the aerosol optical thickness for two wind direction sectors - northern sector 270o-N-90o and southern sector 90o-S-270o - is analysed.
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Solar radiation fluxes at the surface of the Baltic Proper. Part 2. Uncertainties and comparison with simple bulk parametrisations
Oceanologia 1999, no 41 (2), pp. 147–185

Hans-Jörg Isemer
Institute for Atmospheric Physics, GKSS-Research Centre, Geesthacht, Germany;isemer@gkss.de

Anna Rozwadowska
Institute of Oceanology, Polish Academy of Sciences, Powstańców Warszawy 55, 81-712 Sopot, Poland

Keywords: solar radiation flux at ground level, Baltic Proper, semi-empirical model, bulk parametrisations, COADS data, BALTEX, continental and marine atmospheres

Manuscript received 2 February 1999, reviewed 24 March 1999, accepted 26 April 1999.
Abstract
An adjusted version of the semi-empirical model developed by Rozwadowska (1991) was applied to calculate monthly and annual estimates of incident solar radiation fluxes at the surface of the Baltic Proper during 1980 to 1992 using voluntary observing ship meteorological observations from COADS as input data. The semi-empirical model was specifically calibrated using measurements from the Baltic Proper region. In Part 1 of this study we described the resulting solar radiation flux climatology for the Baltic Proper as well as for its three sub-basins. In this second part, we give estimates of the overall random and systematic errors of the climatological flux results, apply simple bulk parametrisations to the same COADS ship observations, and compare the results with those of the semi-empirical model presented in Part 1. This comparison shows that bulk parametrisations calibrated both in purely marine and in continental environments elsewhere on the globe produce surface radiation climates over the Baltic Proper which deviate systematically, in a seasonally and regionally varying manner, from the results of the semi-empirical model. We present evidence to show that the differences found may be due both to physical reasons and to problems with the calibration methodology. This indicates that the atmospheric conditions over the Baltic Sea require specific, regionally calibrated models and parametrisations for solar surface radiation. We suggest that international efforts be made in order, firstly, to build up inventories and accessible data compilations of existing surface radiation records from the Baltic Sea, and secondly, to initiate additional surface radiation measurement activities based on internationally accepted and co-ordinated strategies. The planned intensive observational and modelling phase of BALTEX scheduled for the years 1999 to 2001 (BRIDGE) would be an ideal start for such initiatives.
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Modelling the influence of acclimation on the absorption properties of marine phytoplankton
Oceanologia 1999, no 41 (2), pp. 187–210

Bogdan Woźniak
Institute of Oceanology, Polish Academy of Sciences, Powstańców Warszawy 55, 81–712 Sopot, Poland;wozniak@iopan.gda.pl

Jerzy Dera
Institute of Oceanology, Polish Academy of Sciences, Powstańców Warszawy 55, 81–712 Sopot, Poland

Dariusz Ficek
Pedagogical University, Arciszewskiego 22, 76-200 Słupsk, Poland

Roman Majchrowski
Pedagogical University, Arciszewskiego 22, 76-200 Słupsk, Poland

Sławomir Kaczmarek
Institute of Oceanology, Polish Academy of Sciences, Powstańców Warszawy 55, 81–712 Sopot, Poland

Mirosława Ostrowska
Institute of Oceanology, Polish Academy of Sciences, Powstańców Warszawy 55, 81–712 Sopot, Poland

Olga I. Koblentz-Mishke
Shirshov Institute of Oceanology, Russian Academy of Sciences, Krasikova 23, 117218 Moscow, Russia

Keywords: phytoplankton absorption, photo-chromatoadaptation, package effect, absorption properties of photoprotecting and photosynthetic pigments

Manuscript received 1 March 1999, reviewed 26 April 1999, accepted 10 May 1999.
Abstract
An algorithm for calculating the marine phytoplankton total spectral absorption coefficient and its components for particular groups of photosynthetic and photoprotecting pigments has been developed. The input data for the calculations are the concentrations of these groups of pigments and depth in the sea. Over 1400 sets of simultaneously measured phytoplankton absorption properties and pigment contents at different depths in various water types were applied in the modelling. Photo- and chromatic acclimation as well as the package effect of pigments in cells and its variation in different waters have been considered. The vertical profiles of the product CI d are also described.
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Sea surface microlayer: a field evaluation of teflon plate, glass plate and screen sampling techniques. Part 1. Thickness of microlayer samples and relation to wind speed
Oceanologia 1999, no. 41 (2), pp. 211-221

Lucyna Falkowska
Institute of Oceanography, Gdańsk University, Piłsudskiego 46, 81–378 Gdynia, Poland; lucy@univ.gda.pl

Keywords: thickness of microlayer, sampling technique, wind speed, open sea (Baltic)

Manuscript received 28 January 1999, reviewed 30 March 1999, accepted 28 April 1999.
Abstract
Surface microlayer samples were collected in the open sea with the simultaneous use of three different techniques. The thinnest water layer, 10 µm on average was collected with a teflon plate (TPM), 90 µm thick samples were collected with a glass plate (GPM) and 250 µm samples with a screen (SM). The sampling was performed under variable weather conditions. The microlayer thickness was found to increase with increasing wind speed. Glass plate and screen samples were influenced by the sea state. The intensification of turbulence in the surface layer was responsible for increased advective transport of organic matter and its accumulation near the sea surface and the greater thickness of the microlayer. When the wind speed exceeded 8 ms-1 (5oB), the microlayer thickness was observed to decrease gradually. The thickness of a microlayer collected by teflon plate was found to be inversely proportional to the wind speed. The classic screen method turned out to be the most useful of the techniques examined because of its relatively short sampling time and large sample volume. This technique is also applicable in inclement weather, when mechanical samplers are useless.
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Sea surface microlayer: a field evaluation of teflon plate, glass plate and screen sampling techniques. Part 2. Dissolved and suspended matter
Oceanologia 1999, no. 41 (2), pp. 223-240

Lucyna Falkowska
Gdańsk University, Al. Marsz. Piłsudskiego 46, 81-378 Gdynia, Poland; lucy@univ.gda.pl

Keywords: microlayer, nutrients, chlorophyll, DOC, POC, ATP, open sea (Baltic)

Manuscript 28 January 1999, reviewed 30 March 1999, accepted 7 May 1999.
Abstract
The similarities and differences in chemical composition of particular sub-layers of the sea microlayer are discussed on the basis of data obtained from the open sea region of the Gdańsk Basin. Three methods of microlayer sampling were tested simultaneously, resulting in sub-samples of different mean thickness (10, 90, 250 µm). Samples were analysed to determine dissolved NO3-, NH4+, PO43-, Ptot and DOC, as well as suspended components (chl a, phae a, ATP, POC, particle size distribution and algae). It was found that the stratified microlayer forms a medium extremely diversified chemically and biologically. Variable ranges of concentration as well as varying frequencies of the depletion or enrichment coefficient in each measurement period indicate disparate conditions in the microlayers, which are related to the intensity of primary production and the destruction of organic matter. Comparative studies provided no evidence for the preferential application of any of the sampling techniques to obtain the most accurate picture of dissolved organic and inorganic substances in the sea surface microlayer. In the case of particulate organic matter, satisfactory results were obtained with the classic screen technique. The article highlights the merit of simultaneous studies by various sampling techniques in answering questions related to the sea surface microstructure and the momentum of photochemical and biological processes at its different levels.
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Wave analysis at Lubiatowo and in the Pomeranian Bay based on measurements from 1997/1998 - comparison with modelled data (WAM4 model)
Oceanologia 1999, no. 41 (2), pp. 241-254

Barbara Paplińska
Institute of Hydro-Engineering, Polish Academy of Sciences, Kościerska 7, 80-953 Gdańsk, Poland;bep@ibwpan.gda.pl

Keywords: sea waves, sea waves modelling, Baltic Sea

Manuscript received 19 February 1999, reviewed 19 April 1999, accepted 29 April 1999.
Abstract
The third generation WAM4 wave model was applied to the Baltic Sea. The computed significant wave height was compared with wave measurements for the periods October-November 1997 and February-May 1998. The calculations were conducted with wind fields obtained from the numerical weather prediction system at present in use as a quasi-operational system at ICM. Statistical analysis indicates good agreement between the modelled and measured significant wave height. Finally, a visualisation of wave fields is presented in the form in which it could be published in a daily meteorological forecast.
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Distribution of triazine-type herbicides in the surface waters of the southern Baltic
Oceanologia 1999, no. 41 (2), pp. 255-265

Ksenia Pazdro
Institute of Oceanology, Polish Academy of Sciences, Powstańców Warszawy 55, 81-712 Sopot, Poland; pazdro@iopan.gda.pl

Jacek Trończynski
IFREMER, P.O. Box 1049, Centre de Nantes, France

Janusz Pempkowiak
Institute of Oceanology, Polish Academy of Sciences, Powstańców Warszawy 55, 81-712 Sopot, Poland;

Keywords:triazines, surface waters, southern Baltic

Manuscript received 2 February 1999, reviewed 10 March 1999, accepted 2 April 1999.
Abstract
Triazine-type herbicides (atrazine, simazine, terbuthylazine, DEA - deethylatrazine) were analysed in the surface waters of the Baltic Sea off Poland in September 1995 and April 1997. Total concentrations varied from 14.7 to 30.0 ng dm-3 in 1995 and from 8.5 to 12.7 ng dm-3 in 1997. Concentrations in offshore samples were much smaller than in inshore ones (15.6±2.2 vs 23.5±4.8) in 1995, while no differences were found in 1997 (9.2±1.8 vs 10.1±2.3). This was attributed to the increased input of triazines to the Baltic Sea with river run-off following the summer application of these substances in agriculture. The ratios of concentrations of individual compounds indicate that terbuthylazine is present in similar proportions in the Pomeranian Bay and the Gulf of Gdańsk (21% vs 20%), despite the ban on the use of atrazine and simazine in Germany imposed in the early 1990s. Similar DEA-to-atrazine indices in both the Pomeranian Bay and the Gulf of Gdańsk (1.20±0.22 vs1.31±0.25) support the inference that the run-off from the rivers Vistula and Odra contributes to the distribution of triazines in the surface waters of the southern Baltic.
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Communications


Phytoplankton blooms - a 'fever' of the Baltic ecosystem
Oceanologia 1999, no. 41 (2), pp. 265-275

Grażyna Kowalewska
Institute of Oceanology, Polish Academy of Sciences, Powst. Warszawy 55, 81–712 Sopot, Poland; kowalewska@iopan.gda.pl

Keywords: phytoplankton blooms, eutrophication, nutrients, Baltic Sea

Manuscript received 4 March 1999, reviewed 26 April 1999, accepted 14 May 1999.
Abstract
This paper examines the phenomenon of Baltic phytoplankton blooms in a new light. They are investigated from the standpoint of the author's own studies of chlorophyll and its derivatives in deep Baltic sediments, and of the influence of inorganic and organic pollutants on unicellular algae. Algal blooms in the Baltic should be perceived as perfectly normal phenomena that are neither time- nor space-specific. At the same time, they are signals given by the basin that something - not necessarily the level of nutrients - has changed in the environment and are a response of the ecosystem to that change.
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