The photosynthetic quotient (PQ) is defined as the molar ratio of oxygen released to the carbon dioxide assimilated during photosynthesis. Calculation of correct PQ values of natural phytoplankton populations is crucial for understanding of carbon budgets but often result in values that differ highly from the expected stoichiometric proportions of photosynthetic products. In the present study, measurements of primary production, that is, CO2 assimilation, performed with the standard isotopic method (14C) and oxygen release estimated during photosynthesis with the light-and-dark bottle method were compared to calculate PQ in the southern Baltic (Gulf of Gdańsk, Poland). The PQ average was 1.28 (ANOVA; F = 872; R2 = 0.92; n = 77; p < 0.001). Neither nitrogen source nor phytoplankton composition was noted to impact PQ values. Very high PQ values in the lower range of production rates (that cannot be explained by the stoichiometric proportion of photosynthesis products) were interpreted as artifacts related to the lower sensitivity of the oxygen method compared to that of the 14C method.
The Ponto-Caspian cladocera Cercopagis pengoi invaded the Baltic Sea in 1992. For the first time it was recorded in the Gulf of Riga and three years later it appeared in the Gulf of Finland. In the summer of 1999 it had been also found in huge numbers in shallow areas (0.5 - 10 m) of the Gulf of Gdańsk.
The aim of the research was to identify the potential for the use of probability density functions (PDF) in modeling of near-surface wind speed. The approaches of Empirical Orthogonal Functions (EOF) and Canonical Correlation Analysis (CCA) are used in combination with 2-parametric Weibull distribution. The downscaling model was built using a diagnosed relationship between sea level pressure (SLP) patterns over Europe and the Northern Atlantic and estimated monthly values of Weibull parameters at 9 stations along the Polish Baltic Coast. The obtained scale (A) and shape (k) parameters make it possible to describe temporal variations of wind fields and their theoretical probability values. This may have further application in the modeling of extreme wind speeds for seasonal forecasting, climate prediction or in historical reconstructions. The model evaluation was done separately for the calibration (1971-2000) and validation periods (2001-2010). The scale parameter was reconstructed reasonably, while there were some problematic issues with the shape parameter, especially in the validation period. The quality of the developed models is generally higher for the winter season, due to larger SLP gradients, whereas the results for the spring and summer seasons were less satisfactory. Despite this, the 99th percentile of theoretical wind speeds are in most cases satisfactory, due to the lesser importance of the shape parameter for typical distributions in the analyzed region.
In an in situ experiment we evaluated the growth of the red algae Furcellaria lumbricalis and Coccotylus truncatus in the Archipelago Sea. The results showed that the growth rates of both species were similar but that growth decreased with increasing algal coverage. The effects were more pronounced for C. truncatus than for F. lumbricalis. Economic analyses aiming to establish sustainable harvesting limits for F. lumbricalis in the study area should take account of the density dependent growth of these red algae.
A total of 943 Anguilla anguilla (only digestive tract and swim bladder) from 3 areas of the south-east Baltic was examined for parasites. The investigation was carried out in July and August 1982-1990. Ten species of parasites were encountered: Deropristis inflata, Bothriocephalus claviceps, Proteocephalus macrocephalus, Raphidascaris acus, Camallanus lacustris, C. truncatus, Acanthocephalus anguillae, A. lucii, Echinorhynchus gadi and Pomphorhynchus laevis.
The microphytobenthic primary production and chlorophyll a content were studied over the annual cycle (May 1998 – May 1999) on a non-tidal Baltic sandy beach at three stations along the beach gradient: littoral, waterline and splash zone. The chlorophyll a concentrations varied between 0.88 and 12.18 μg cm−3. Net and gross primary production rates respectively lay within the ranges 0.1–31.4 mgC m−2 h−1 and 0.2–41.8 mgC m−2 h−1. The highest values of both Chl a content and primary production were noted at the littoral station, the lowest ones at the waterline. The mean annual P/B ratio was highest at the waterline. The differences in Chl a content between stations were statistically significant and may be related to water dynamics, resuspension and water content. Production rates were highly variable on monthly time scales, and the highest results at all the study locations were noted in July. The gross photosynthetic rates were significantly correlated with water temperature.
Analysed by differential spectroscopy, 1208 empirical spectra of light absorption apl(λ) by Baltic phytoplankton were spectrally decomposed into 26 elementary Gaussian component bands. At the same time the composition and concentrations of each of the 5 main groups of pigments (chlorophylls a, chlorophylls b, chlorophylls c, photosynthetic carotenoids and photoprotecting carotenoids) were analysed in 782 samples by HPLC. Inspection of the correlations between the intensities of the 26 elementary absorption bands and the concentrations of the pigment groups resulted in given elementary bands being attributed to particular pigment groups and the spectra of the mass-specific absorption coefficients established for these pigment groups. Moreover, balancing the absorption effects due to these 5 pigment groups against the overall absorption spectra of phytoplankton suggested the presence of a sixth group of pigments, as yet unidentified (UP), undetected by HPLC. Apr eliminary mathematical description of the spectral absorption properties of these UP was established. Like some forms of phycobilins, these pigments are strong absorbers in the 450–650 nm spectral region. The packaging effect of pigments in Baltic phytoplankton was analysed statistically, then correlated with the concentration of chlorophyll a in Baltic water. As a result, a Baltic version of the algorithm of light absorption by phytoplankton could be developed. This algorithm can be applied to estimate overall phytoplankton absorption spectra and their components due to the various groups of pigments from a knowledge of their concentrations in Baltic water.