Present and Past‐Millennial Eutrophication in the Gulf of Gdańsk (Southern Baltic Sea)

Eutrophication is manifested by increased primary production leading to oxygen depletion in near‐bottom water and toxic cyanobacteria blooms. This is an important contemporary problem of the Baltic Sea and many other coastal waters. The present eutrophication is mainly ascribed to anthropogenic activity. To compare the present trophic state with that during past millennia, two sediment cores (50 cm long and ~400 cm long covering ca. 5,500 years) were taken from the Gulf of Gdańsk (southern Baltic Sea). The core subsamples were analyzed for phytoplankton pigments (chlorophylls and their derivatives, and carotenoids). In addition, carbon (Ctot, Corg, and δ13C), 14C dating, grain size, diatoms, and selected metals in the cores were analyzed to determine conditions in the depositional environment. The results indicated that there were high primary production periods in the past, during the Littorina Sea and the Roman Climatic Optimum, accompanied by oxygen deficiency in the near‐bottom water, most probably caused by climate warming. The ratio of 132,173‐cyclopheophorbide‐a enol, a labile degradation product of chlorophyll‐a, to the sum of other chloropigments‐a (CPPB‐aE/ΣChlns‐a) is proposed as a new paleoredox proxy. Heterocystous cyanobacteria blooms of an intensity similar to or even greater than at present also occurred in past millennia and were connected with climate warming. Hence, eutrophication must have occurred in the past, which means that natural factors have a substantial influence on it.publishedVersion© 2019. American Geophysical Union

Distribution and fate of polycyclic aromatic hydrocarbons (PAHs) in recent sediments from the Gulf of Gdańsk (SE Baltic)

Polycyclic aromatic hydrocarbons (PAHs) were determined in recent (0-10 cm) sediments from the Gulf of Gdańsk during 2003-07 andcorrelated with environmental parameters. Located in the south-eastern part of the Baltic and receiving the waters of the River Wisła(Vistula), this area of negligible tides and strong anthropogenic stress, highly eutrophic as a consequence, is an exceptionalmodel basin for studying the fate of hydrophobic organic contaminants introduced to the sea. Environmental conditions determine thedistribution and composition patterns of parent PAHs in Gulf of Gdańsk sediments. PAHs were associated mainly with fine particlesediments, rich in organic carbon, with hypoxia/anoxia near the bottom. The highest PAH contents were found in the Gdańsk Deep(ca 110 m), where the mean concentration of <span style="font-size:1.5em;">&Sigma;</span>12PAHs was &#126;3600 ng g^-1, and no distinct temporal trend was observed.Lighter PAHs were found to be depleted in deeper regions. It was estimated that the Wisła discharges &#126;50% of the total PAH load deposited in recent Gulf sediments

Vertical profiles of sedimentary polycyclic aromatic hydrocarbons and black carbon in the Gulf of Gdańsk (Poland) and Oslofjord/Drammensfjord (Norway), and their relation to regional energy transitions

The analysis of undisturbed sediment cores is a powerful tool for understanding spatial and temporal impacts of anthropogenic emissions from the energy and transport sectors at a regional scale. The spatial and vertical distribution of polycyclic aromatic hydrocarbons (PAHs) and black carbon (BC) were determined in 12 cores of recent (up to 20 cm long) sediments from the Gulf of Gdańsk in Poland, and Oslofjord/Drammensfjord in Norway. The Σ12PAHs levels in individual sediment layers varied from 250 to 4500 ng/g d.w. in the Gulf of Gdańsk, and from 210 to 4580 ng/g d.w. in the Norwegian fjords. Analysis of PAH ratios indicates that PAHs in both studied areas originated mainly from pyrogenic sources. The BC concentrations in sediments were up to 0.9% and were generally higher in the Gulf of Gdańsk (mean - 0.39%) than in Oslofjord/Drammensfjord (mean - 0.19%). The deposition history of anthropogenic emissions over the last 100 years was reconstructed based on the analysis of dated and well-laminated sediment cores from two stations from the Gulf of Gdańsk and two stations from the Norwegian fjords. The evolution in energy structure was especially evident in the Oslofjord, where transition from fossil fuel combustion to hydropower after 1960 coincided with a sharp decrease in sedimentary PAHs. Despite significant changes in the economic development in Poland, temporal patterns in PAH concentrations/profiles in the Gulf of Gdańsk were not as obvious. The historical PAH trends in the Gulf of Gdańsk may be related to the overwhelming PAH inputs from domestic combustion of solid fuels (coal, wood) for heating purposes. The implementation of legislation and other activities addressed to restrict the use of solid fuels in residential heating should reduce PAH emissions.Vertical profiles of sedimentary polycyclic aromatic hydrocarbons and black carbon in the Gulf of Gdańsk (Poland) and Oslofjord/Drammensfjord (Norway), and their relation to regional energy transitionsacceptedVersio

Factors affecting the occurrence of algae on the Sopot beach (Baltic Sea)

This study was financed by the EU CosCo project ("Regional cycle development through coastal co-operation - sea grass and algae focus" - INTERREG IIIC 2N00251) and the statutory IO PAS programme.AbstractThe occurrence of algae on the Sopot beach was investigated from 2004 to 2006 from the beach management point of view. Various methods were applied in an attempt to understand the mechanisms underlying the accumulation of algae on the shoreline. They included daily observations of the occurrence of macrophyta on the beach, absorption measurements of acetone extracts of the particulate matter in the seawater, the collection of macrophyta and phytoplankton samples for biomass and taxonomic identification, and determination of the degree of decomposition on the basis of chloropigment analyses. The results were related to the environmental conditions: meteorological data and the physico-chemical parameters of the seawater. The biomass recorded on the beach consisted mainly of macroalgae and a small proportion of sea grass (Zostera marina). The phytoplankton biomass consisted mainly of dinoflagellates, diatoms, cyanobacteria, euglenoids and cryptophytes. The conclusions to be drawn from this work are that the occurrence of huge amounts of macrophyta amassing on the Sopot beach depends on the combined effect of high solar radiation in spring and summer, high-strength (velocity × frequency) south-westerly winds in May-September, followed by northerly winds, bringing the macrophyta from Puck Bay on to the Sopot beach. At the same time, their abundance along the beach varies according to the shape and height of the shore, the wind strength and the local wind-driven seawater currents. According to estimates, from 2.2-4.4 × 102 tons (dry weight) of macrophyta can be moved on to the Sopot beach in one hour. In October, strong south-easterly winds can also transport huge amounts of decomposing biomass onshore. The phytoplankton content in the total biomass is negligible, even though at low concentrations its biological activity may be considerable. The intensive phytoplankton blooms observed on the Sopot beach in summer are not always caused by cyanobacteria