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Seasonal changes in particulate organic matter (POM) concentrations and properties measured from deep areas of the Baltic Sea

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Winogradow A., Mackiewicz A., Pempkowiak J.
Oceanologia
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2019
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tom 61
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nr 4
2
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Could submarine groundwater discharge be a significant carbon source to the Southern Baltic Sea?

100%
Szymczycha B., Maciejewska A., Winogradow A., Pempkowiak J.
Oceanologia
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2014
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tom 56
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nr 2
3
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Diurnal and seasonal DOC and POC variability in the land-locked sea

88%
Szymczycha B., Winogradow A., Kulinski K., Koziorowska K., Pempkowiak J.
Oceanologia
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2017
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tom 59
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nr 3
Organic matter is a minor yet important component of the marine environment. The aim of this study was to investigate the diurnal and seasonal changes in dissolved and particulate organic carbon (DOC and POC, respectively). Thus, DOC and POC as well as chlorophyll a (Chl a), δ13C, NO3−, NO2−, NH4+, PO43−, salinity, pH, and temperature were regularly measured in samples collected for 24 h (2-h resolution) in the Gdańsk Deep (54°44.730′N, 19°08.531′E) at three water depths (1, 10, and 40 m) during sampling campaigns in 2011 (May), 2014 (May), and 2015 (January, March, May, July, September, November). Seasonal variations in DOC and POC followed the seasonality of Chl a (proportional trend) and nutrients (reverse trend) concentrations. Diurnal oscillations were detected in six out of the eight measurement series. The strongest diurnal variability in both POC and DOC occurred in May 2011 and March 2015, when phytoplankton activity was highest (high Chl a). The surprisingly low δ13C values (range: −28‰ to −24‰) measured over the course of the study revealed the gaps in our knowledge of the isotopic characteristics of terrestrial- vs. marine-derived particulate organic matter.
4
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Tracking trends in eutrophication based on pigments in recent coastal sediments

76%
Szymczak-Zyla M., Krajewska M., Winogradow A., Zaborska A., Breedveld G. D., Kowalewska G.
Oceanologia
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2017
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tom 59
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nr 1
Eutrophication in two different coastal areas — the Gulf of Gdańsk (southern Baltic) and the Oslofjord/Drammensfjord (Norway) — both subject to human pressure and with restricted water exchange with adjacent seas, was investigated and compared. Sediment cores (up to 20 cm long) were collected at 12 stations using a core sampler, 6 in each of the two areas, and divided into sub-samples. The physicochemical parameters characterizing the adjacent water column and near-bottom water, i.e. salinity, oxygen concentration and temperature, were measured during sample collection. Chlorophylls-a, -b and -c, their derivatives and selected carotenoids were determined for all the samples, as were additional parameters characterizing the sediments, i.e. Corg, Ntot, d13C and d15N, grain size. 210Pb activity was also determined and on that basis sediment mixing and accumulation rates were estimated. The distribution of pigments in sediments was related to environmental conditions, the sampling site location and sediment characteristics. The results are in agreement with other observations that eutrophication in the Gulf of Gdańsk has increased, especially since the 1970s, whereas in the Oslofjord it decreased during the same period. The pigments are better preserved in inner Oslofjord sediments than in those from the Gulf of Gdańsk. The results demonstrate that the sum of chloropigments-a insediments calculated per dry weight of sediments is a valuable measure of eutrophication, providing that the monitoring site is selected properly, i.e. sediments are hypoxic/anoxic and non-mixed. Besides, the results confirm previous observations that the percentages of particular chlorophyll-a derivatives in the sum of chloropigments-a are universal markers of environmental conditions in a basin. The ratios of chloropigments-b and chlorophylls-c to the sum of chloropigments-a (SChlns-b/ SChlns-a; Chls-c/SChlns-a) may by applied as complementary markers of freshwater and marine organic matter input, respectively.
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