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Species-level associations of phytoplankton with environmental variability in the Neva Estuary (Baltic Sea)

Golubkov Mikhail, Nikulina Vera, Golubkov Sergey

Oceanologia

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2021

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No. 63 (1)

149--162

EN

Changes in phytoplankton communities due to anthropogenic nutrient load and climate change often lead to eutrophication and harmful algal blooms that can affect biogeochemical cycling. However, little is known about the specific responses of various species to environmental variables. 17-year long data on the midsummer phytoplankton biomass in the Neva Estuary were analyzed to show the changes in the composition of phytoplankton in relation to water depth, transparence, salinity, temperature, concentrations of total phosphorus and chlorophyll a, and plankton primary production. One hundred seventy-four species and forms from eight taxonomic classes were found in phytoplankton. Fifteen species were potentially harmful. The most diverse and abundant groups were cyanobacteria, green algae and diatoms. Canonical Correspondence Analysis showed that the biomass of various species from each phytoplankton group correlated differently with environmental factors. However, within each group, there were some predominant trends in the correlative response to changes in environmental variables. The biomass of cyanobacteria was high in the middle and lower reaches of the estuary and, in general, positively correlated with water salinity. The biomass of most species of green algae and diatoms correlated negatively with it. These algae showed a positive trend in biomass in the upper and middle reaches of the estuary during the last decades that may be explained by changes in weather conditions. Taking into account that climate models predict future increases in precipitation and temperature in the northern Baltic, the future expansion of freshwater phytoplankton species in estuaries of the northern Baltic Sea is very likely.

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Influence of climate parameters on long-term variations of the distribution of phytoplankton biomass and nutrient concentration in the Baltic Sea simulated by a 3D model

Dzierzbicka-Głowacka L., Piskozub J., Jakacki J., Janecki M., Nowicki A.

Polish Journal of Ecology

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2012

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Vol. 60, nr 4

651--666

EN

We used a 3-D coupled seaice ecological model of the Baltic Sea to investigate the influence of long-term trends in average temperature, wind speed and solar irradiance on nutrients concentration and distribution of phytoplankton. We tested the sensitivity of the model to changes of the main physical parameters such as temperature, wind speed, solar and thermal radiation performing several numerical experiments with different configurations. Discussion about the relevance of the results for the expected future climate change is provided. The calculations were done for whole Baltic Sea for the period from 2004 to 2048. The results of the numerical simulations for the different areas of Baltic Sea (nine stations: Gulf of Gdańsk, Gdańsk Deep, Gotland Deep, Bornholm Deep, Gulf of Finland, Gulf of Riga, Gulf of Bothnian, Bothnian Sea, Danish Straits) were presented. The simulations results show significant changes in phytoplankton biomass and nutrient concentration distributions, which took place in the regions where a significant increase in currents (to 100 cm s-1) was found. The results of the numerical simulations for five years (2000–2004) are consistent with in situ observations for temperature and phytoplankton (Dzierzbicka-Glowacka et al. 2011b).

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Long term observations of a 3-span highway corrugated steel box bridge on Gniezno Bypass

Madaj A., Węgrzynowski M., Janusz L.

Archiwum Instytutu Inżynierii Lądowej

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2012

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Nr 12

197-203

EN

The paper describes 5 years of behavior of a corrugated steel box 3 span bridge with a 14.1m span. The bridge is located on Gniezno by-pass in Poland. After few months of operation road surface over the bridge showed signs of ruts. An expertise was performed to evaluate causes of rut formation and provide suggestions for repair of the bridge. Deformations of road surface, structure and foundations wer measured.

PL

Praca opisuje 5-letnie zachowanie trójprzęsłowego mostu skrzynkowego o rozpiętości 14,1 m. Most znajduje się na obwodnicy Gniezna w Polsce. Po kilku miesiącach użytkowania na powierzchni drogi nad mostem pojawiły się koleiny. Przeprowadzono badanie w celu oceny przyczyn powstawania kolein i przygotowania propozycji naprawy mostu. Dokonano pomiarów odkształceń powierzchni drogi, konstrukcji mostu oraz fundamentów.