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1

A study of the Baltic water optical transparency

100%

Dera J. , Sagan S.

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tom 28

2

Inherent optical properties and particulate matter distribution in summer season in waters of Hornsund and Kongsfjordenen, Spitsbergen

100%

Sagan S. , Darecki M.

Oceanologia

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2018

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tom No. 60 (1)

65--75

EN

Two Spitsbergen fjords, Hornsund and Kongsfjorden, are known for being under different hydrological regimes. The first is cold, separated from warm Atlantic water by East Spitsbergen Current, while Kongsfjorden is frequently penetrated by relatively warm Atlantic water. On the other hand, both are under strong influence of water discharge from glaciers and land freshwater input. During the period of observation in both fjords a dominant water mass was Surface Water, which originates mainly from glacial melt. The presence of suspended matter introduced with melt water in Surface Water is reflected by highest values of light attenuation and absorption coefficients recorded in areas close to glacier both in Hornsund and Kongsfjorden. In Hornsund the maximum light attenuation coefficient cpg(555) was 5.817 m−1 and coefficient of light absorption by particles ap(676) = 0.10 m−1. In Kongsfjorden the corresponding values were 26.5 m−1and 0.223 m−1. In Kongsfjorden suspended matter of the size class 20-200 μm dominated over fractions smaller than 20 μm while in Hornsund dominating size fraction was 2-20 μm. The results provide an evidence of considerable range of variability of the optical properties mainly due to glacial and riverine runoff. The scale of variability of particulate matter in Kongsfjorden is bigger than in Hornsund. Most of the variability in Hornsund can be attributed to glaciers discharge and a presence of particles of mineral origin, while in Kongsfjorden the organic and mineral particles contribute almost equally to defining the optical properties of water.

3

Inherent optical properties and particulate matter distribution in summer season in waters of Hornsund and Kongsfjorden, Spitsbergen

100%

Sagan S. , Darecki M.

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tom 60

|

nr 1

EN

Two Spitsbergen fjords, Hornsund and Kongsfjorden, are known for being under different hydrological regimes. The first is cold, separated from warm Atlantic water by East Spitsbergen Current, while Kongsfjorden is frequently penetrated by relatively warm Atlantic water. On the other hand, both are under strong influence of water discharge from glaciers and land freshwater input. During the period of observation in both fjords a dominant water mass was Surface Water, which originates mainly from glacial melt. The presence of suspended matter introduced with melt water in Surface Water is reflected by highest values of light attenuation and absorption coefficients recorded in areas close to glacier both in Hornsund and Kongsfjorden. In Hornsund the maximum light attenuation coefficient cpg(555) was 5.817 m−1 and coefficient of light absorption by particles ap(676) = 0.10 m−1. In Kongsfjorden the corresponding values were 26.5 m−1 and 0.223 m−1. In Kongsfjorden suspended matter of the size class 20–200 μm dominated over fractions smaller than 20 μm while in Hornsund dominating size fraction was 2–20 μm. The results provide an evidence of considerable range of variability of the optical properties mainly due to glacial and riverine runoff. The scale of variability of particulate matter in Kongsfjorden is bigger than in Hornsund. Most of the variability in Hornsund can be attributed to glaciers discharge and a presence of particles of mineral origin, while in Kongsfjorden the organic and mineral particles contribute almost equally to defining the optical properties of water.

4

Fluorescence measured in situ as a proxy of CDOM absorption and DOC concentration in the Baltic Sea

80%

Kowalczuk P. , Zabłocka M. , Sagan S. , Kuliński K.

Oceanologia

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2010

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tom No. 52 (3)

431-471

EN

This study presents results from field surveys performed in 2008 and 2009 in the southern Baltic in different seasons. The main goal of these measurements was to identify the empirical relationships between DOM optical properties and DOC. CDOM absorption and fluorescence and DOC concentrations were measured during thirteen research cruises. The values of the CDOM absorption coefficient at 370 nm aCDOM(370) ranged from 0.70 m-1 to 7.94 m-1, and CDOM fluorescence intensities (ex./em. 370/460) IFl, expressed in quinine sulphate equivalent units, ranged from 3.88 to 122.97 (in filtered samples). Dissolved organic carbon (DOC) concentrations ranged from 266.7 to 831.7 žM C. There was a statistically significant linear relationship between the fluorescence intensity measured in the filtered samples and the CDOM absorption coefficient aCDOM(370), R2 = 0.87. There was much more scatter in the relationship between the fluorescence intensity measured in situ (i.e. in unprocessed water samples) and the CDOM absorption coefficient aCDOM(370), resulting in a slight deterioration in the coefficient of determination R2 = 0.85. This indicated that the presence of particles could impact fluorometer output during in situ deployment. A calibration experiment was set up to quantify particle impact on the instrument output in raw marine water samples relative to readings from filtered samples. The bias calculated for the absolute percentage difference between fluorescence intensities measured in raw and filtered water was low (-2.05%), but the effect of particle presence expressed as the value of the RMSE was significant and was as high as 35%. Both DOM fluorescence intensity (in raw water and filtered samples) and the CDOM absorption coefficient aCDOM(370) are highly correlated with DOC concentration. The relationship between DOC and the CDOM absorption coefficient aCDOM(370) was better (R2 = 0.76) than the relationship between DOC and the respective fluorescence intensities measured in filtered and raw water (R2 = 0.61 and R2 = 0.56). The seasonal cycle had an impact on the relationship between DOC and CDOM optical properties. The hyperbolic relationships between aCDOM(370) vs. carbon-specific absorption coefficient a*CDOM(370), and IFl vs. the ratio of fluorescence intensity to organic carbon concentration IFl/DOC were very good. The discharge and mixing of riverine waters is a primary driver of variability in DOC and CDOM optical properties in the surface waters of the southern Baltic Sea, since all the parameters considered are negatively correlated with salinity. It was found that there was a positive trend of increasing values of DOM optical parameters with salinity increase (within a range of 8-12) in deep water below the permanent pycnocline. Evidence is also presented to show that late-summer photodegradation was responsible for the depletion of CDOM florescence intensities in the mixed layer above the seasonal thermocline. It was further demonstrated that the DOC concentration increases in the stagnant waters of the Baltic Sea deeps. The Integrated Optical-Hydrological Probe, which registers high-resolution vertical profiles of salinity, temperature, CDOM and the optical properties of water, confirmed that DOM optical proxies can be used in studies of DOM biogeochemical cycles in the Baltic Sea.

5

Relationships between inherent optical properties in the Baltic Sea for application to the underwater imaging problem

80%

Levin I. , Darecki M. , Sagan S. , Radomyslskaya T.

Oceanologia

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2013

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tom 55

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nr 1

6

Fluorescence measured in situ as a proxy of CDOM absorption and DOC concentration in the Baltic Sea

80%

Kowalczuk P. , Zablocka M. , Sagan S. , Kulinski K.

Oceanologia

|

2010

|

tom 52

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nr 3

431-471

7

Focusing of sunlight by sea surface waves : new results from the Black Sea

80%

Dera J. , Sagan S. , Stramski D.

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tom 34

8

Polish student expedition to the Hornsund Fiord in Spitsbergen

70%

Adamek A. , Kurczyński Z. , Pachuta A. , Piskorz M. , Sagan S.

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2004

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tom nr 2/69

341--346

9

Seasonal changes in selected optical parameters in the Pomeranian Bay in 1996-1997

70%

Kowalczuk P. , Sagan S. , Olszewski J. , Darecki M. , Hapter R.

Oceanologia

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1999

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tom No. 41 (3)

309-334

EN

The main task of the Joint Polish-German Pomeranian Bay Project was to achieve a better understanding of the impact of freshwater discharge on this environment. The freshwater from the River Odra enters the Pomeranian Bay through four outlets. The most important of these is the River Swina, as it carries the largest volume of water exchange between the bay and the Szczecin Lagoon. This freshwater carries a large load of optically active substances: dissolved organic materials, mineral and organic sediments, as well as nutrients, which boost phytoplankton growth. The effect of riverine discharge can be traced with the use of optical methods. The elevated level of optically active components can significantly reduce the light required for photosynthesis. The Institute of Oceanology carried out a survey of selected inherent and apparent optical properties in the Pomeranian Bay in three seasons in 1996 and 1997. The results are presented and discussed, as are the relations between the various optical parameters and salinity.

10

Seasonal changes in selected optical parameters in the Pomeranian Bay in 1996-1997

70%

Kowalczuk P. , Sagan S. , Olszewski J. , Darecki M. , Hapter R.

Oceanologia

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1999

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tom 41

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nr 3

11

Regional Oceanographic Database as a Modern Sea Research Tool

61%

Piskozub J. , Poraziński K. , Sagan S. , Walczowski W. , Wichorowski M. , Wyrwiński J.

TASK Quarterly : scientific bulletin of Academic Computer Centre in Gdansk

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2000

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tom Vol. 4, No 1

127-136

EN

Based on the experience acquired from working on the Regional Oceanographic Database at the IOPAS in Sopot a general view of database as a tool for supporting scientific research was presented. Article describes general structure, data flow and techniques of using the ROD.

12

A study of episodic events in the Baltic Sea – combined in situ and satellite observations

41%

Lysiak-Pastuszak E. , Bartoszewicz M. , Bradtke K. , Darecki M. , Drgas N. , Kowalczuk P. , Krasniewski W. , Krezel A. , Krzyminski W. , Lewandowski L. , Mazur-Marzec H. , Piliczewski B. , Sagan S. , Sutryk K. , Witek B.

Oceanologia

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2012

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tom 54

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nr 2

EN

A project was developed concerning the operational system of surveillance and the recording of episodic events in the Baltic Sea. In situ information was to be combined with multi-sensory satellite imagery to determine the extent of algal blooms, to track their evolution and that of rapid environmental events like hydrological fronts. The main element of the system was an autonomous Ferry Box module on a ferry operating between Gdynia and Karlskrona, automatically measuring temperature, salinity and chlorophyll a fluorescence. At pre-selected locations, discrete water samples were collected, which were subsequently analysed for their phytoplankton content, and algal hepato- and neurotoxins; they were also used in toxicity tests with Artemia franciscana.