Distribution of the volume activity of man-made radionuclides in the surface waters and depth waters of the Baltic Sea in the fall of 1989

Abstract. Deoxygenation in the Baltic Sea endangers fish yields and favours noxious algal blooms. Yet, vertical transport processes ventilating the oxygen-deprived waters at depth and replenishing nutrient-deprived surface waters (thereby fuelling export of organic matter to depth), are not comprehensively understood. Here, we investigate the effects of the interaction between surface currents and winds (also referred to as eddy/wind effects) on upwelling in an eddy-rich general ocean circulation model of the Baltic Sea. Contrary to expectations we find that accounting for current/wind effects does inhibit the overall vertical exchange between oxygenated surface waters and oxygen-deprived water at depth. At major upwelling sites, however, as e.g. off the south coast of Sweden and Finland, the reverse holds: the interaction between topographically steered surface currents with winds blowing over the sea results in a climatological sea surface temperature cooling of 0.5 K. This implies that current/wind effects drive substantial local upwelling of cold and nutrient-replete waters.

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Nitrate source identification in the Baltic Sea using its isotopic ratios in combination with a Bayesian isotope mixing model

Biogeosciences ◽

10.5194/bg-11-4913-2014 ◽

2014 ◽

Vol 11 (17) ◽

pp. 4913-4924 ◽

Cited By ~ 25

Author(s):

F. Korth ◽

B. Deutsch ◽

C. Frey ◽

C. Moros ◽

M. Voss

Keyword(s):

Atmospheric Deposition ◽

Baltic Sea ◽

Surface Waters ◽

N2 Fixation ◽

Source Identification ◽

Agricultural Land ◽

Mixing Model ◽

The Baltic Sea ◽

Bayesian Isotope Mixing Model ◽

The Baltic

Abstract. Nitrate (NO3−) is the major nutrient responsible for coastal eutrophication worldwide and its production is related to intensive food production and fossil-fuel combustion. In the Baltic Sea NO3− inputs have increased 4-fold over recent decades and now remain constantly high. NO3− source identification is therefore an important consideration in environmental management strategies. In this study focusing on the Baltic Sea, we used a method to estimate the proportional contributions of NO3− from atmospheric deposition, N2 fixation, and runoff from pristine soils as well as from agricultural land. Our approach combines data on the dual isotopes of NO3− (δ15N-NO3− and δ18O-NO3−) in winter surface waters with a Bayesian isotope mixing model (Stable Isotope Analysis in R, SIAR). Based on data gathered from 47 sampling locations over the entire Baltic Sea, the majority of the NO3− in the southern Baltic was shown to derive from runoff from agricultural land (33–100%), whereas in the northern Baltic, i.e. the Gulf of Bothnia, NO3− originates from nitrification in pristine soils (34–100%). Atmospheric deposition accounts for only a small percentage of NO3− levels in the Baltic Sea, except for contributions from northern rivers, where the levels of atmospheric NO3− are higher. An additional important source in the central Baltic Sea is N2 fixation by diazotrophs, which contributes 49–65% of the overall NO3− pool at this site. The results obtained with this method are in good agreement with source estimates based upon δ15N values in sediments and a three-dimensional ecosystem model, ERGOM. We suggest that this approach can be easily modified to determine NO3− sources in other marginal seas or larger near-coastal areas where NO3− is abundant in winter surface waters when fractionation processes are minor.

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Dissolved iron (II) in the Baltic Sea surface water and implications for cyanobacterial bloom development

Biogeosciences Discussions ◽

10.5194/bgd-6-3803-2009 ◽

2009 ◽

Vol 6 (2) ◽

pp. 3803-3850 ◽

Cited By ~ 4

Author(s):

E. Breitbarth ◽

J. Gelting ◽

J. Walve ◽

L. J. Hoffmann ◽

D. R. Turner ◽

...

Keyword(s):

Baltic Sea ◽

Surface Waters ◽

Cyanobacterial Bloom ◽

Euphotic Zone ◽

Strong Wind ◽

Ferrous Ions ◽

The Baltic Sea ◽

High Concentrations ◽

Wind Events ◽

The Baltic

Abstract. Iron chemistry measurements were conducted during summer 2007 at two distinct locations in the Baltic Sea (Gotland Deep and Landsort Deep) to evaluate the role of iron for cyanobacterial bloom development in these estuarine waters. Depth profiles of Fe(II) were measured by chemiluminescent flow injection analysis (CL-FIA) and reveal several origins of Fe(II) to the water column. Photoreduction of Fe(III)-complexes and deposition by rain are main sources of Fe(II) (up to 0.9 nmol L−1) in light penetrated surface waters. Indication for organic Fe(II) complexation resulting in prolonged residence times in oxygenated water was observed. Surface dwelling heterocystous cyanobacteria where mainly responsible for Fe(II) consumption in comparison to other phytoplankton. The significant Fe(II) concentrations in surface waters apparently play a major role in cyanobacterial bloom development in the Baltic Sea and are a major contributor to the Fe requirements of diazotrophs. Second, Fe(II) concentrations up to 1.44 nmol L−1 were observed at water depths below the euphotic zone, but above the oxic anoxic interface. Finally, all Fe(III) is reduced to Fe(II) in anoxic deep water. However, only a fraction thereof is present as ferrous ions (up to 28 nmol L−1) and was detected by the CL-FIA method applied. Despite their high concentrations, it is unlikely that ferrous ions originating from sub-oxic waters could be a temporary source of bioavailable iron to the euphotic zone since mixed layer depths after strong wind events are not deep enough in summer time.

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Model-predicted occurrence of multiple pharmaceuticals in Swedish surface waters and their flushing to the Baltic Sea

Environmental Pollution ◽

10.1016/j.envpol.2017.01.062 ◽

2017 ◽

Vol 223 ◽

pp. 595-604 ◽

Cited By ~ 11

Author(s):

C. Lindim ◽

J. van Gils ◽

I.T. Cousins ◽

R. Kühne ◽

D. Georgieva ◽

...

Keyword(s):

Baltic Sea ◽

Surface Waters ◽

The Baltic Sea ◽

The Baltic

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Structure of the specific activity fields of man-made radionuclides extracted from the surface waters of the baltic sea in autumn of 1986 and 1987

Soviet Atomic Energy ◽

10.1007/bf02069717 ◽

1990 ◽

Vol 68 (1) ◽

pp. 16-23 ◽

Cited By ~ 2

Author(s):

D. B. Styro ◽

Zh. V. Bumyalene ◽

G. I. Kadzhene ◽

I. V. Kleiza ◽

M. V. Lukinskene ◽

...

Keyword(s):

Baltic Sea ◽

Surface Waters ◽

Specific Activity ◽

The Baltic Sea ◽

The Baltic

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PFASs in Finnish Rivers and Fish and the Loading of PFASs to the Baltic Sea

Water ◽

10.3390/w11040870 ◽

2019 ◽

Vol 11 (4) ◽

pp. 870 ◽

Cited By ~ 2

Author(s):

Junttila ◽

Vähä ◽

Perkola ◽

Räike ◽

Siimes ◽

...

Keyword(s):

Baltic Sea ◽

Surface Waters ◽

Aquatic Environment ◽

Perca Fluviatilis ◽

Quality Standard ◽

Clupea Harengus ◽

The Baltic Sea ◽

Open Sea ◽

Polluted Sites ◽

The Baltic

The concentrations of per- and polyfluoroalkyl substances (PFASs) in the Finnish aquatic environment were measured in riverine waters and in inland, coastal and open sea fish. In addition, the PFAS load to the Baltic Sea from 11 rivers was calculated. Measurements show that PFASs, including restricted perfluorooctane sulfonic acid (PFOS), are widely present in the Finnish aquatic environment. At three out of 45 sampling sites, the concentration of PFOS in fish exceeded the environmental quality standard (EQS) of the Water Framework Directive (WFD). The annual average (AA) ∑23PFAS concentration in surface waters ranged from 1.8 to 42 ng L−1 and the concentration of PFOS exceeded the AA-EQS in three out of 13 water bodies. In European perch (Perca fluviatilis) and Baltic herring (Clupea harengus membras), the ∑PFAS concentration ranged from 0.98 to 1 µg kg−1 f.w. (fresh weight) and from 0.2 to 2.4 µg kg−1 f.w., respectively. The highest concentrations in both surface water and fish were found in waters of southern Finland. The riverine export of ∑10PFAS to the Baltic Sea from individual rivers ranged from 0.4 kg yr−1 to 18 kg yr−1. PFAS concentrations in fish of point-source-polluted sites and coastal sites were higher compared to fish of open sea or diffusely polluted sites. The PFAS profiles in surface waters of background sites were different from other sites. This study shows that PFASs are widely found in the Finnish aquatic environment. Different PFAS profiles in samples from background areas and densely populated areas indicate diverse sources of PFASs. Although atmospheric deposition has a substantial influence on PFAS occurrence in remote areas, it is not the dominant source of all PFASs to the aquatic environment of Finland. Rather, wastewaters and presumably contaminated land areas are major sources of PFASs to this aquatic environment.

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