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1
Artykuł dostępny w postaci pełnego tekstu - kliknij by otworzyć plik
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Spatial variability of recent sedimentation rates in the Eastern Gotland Basin (Baltic Sea)

100%
Hille S., Leipe T., Seifert T.
Oceanologia
|
2006
|
tom 48
|
nr 2
In order to study recent sedimentation rates in the Eastern Gotland Basin, 52 short sediment cores collected from the deepest part (<150 m)of the Basin in 2003 were investigated. The upper parts of all the cores were distinctly laminated and dark in colour, followed by a homogeneous, greyish lower part. The thickness of the laminated sequences varied from 17 to 300 mm. 210Pb dating analyses of selected cores revealed that the change from non-laminated to laminated sediments happened about 100 years ago, indicating a shift from predominantly oxic bottom water conditions to anoxic conditions. Used as a time marker, this shift in the sediment texture enabled sediment accumulation rates to be estimated for all sediment cores. The observed mean linear sedimentation rate for the whole basin was 0.93 ± 0.67 mm yr−1. The respective bulk sediment accumulation rates ranged from 10.5 to 527 g m−2 yr−1 with an average of 129 ± 112 g m−2 yr−1, indicating a high spatial variability of sedimentation rates within the basin. This agrees very well with the long-term sedimentation pattern since the Litorina transgression. The observed pattern clearly reflects the hydrographic conditions at the seafloor as studied by modelled near-bottom current velocities.
2
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Sedimentary deposition and reflux of phosphorus (P) in the Eastern Gotland Basin and their coupling with P concentrations in the water column

100%
Hille S., Nausch G., Leipe T.
Oceanologia
|
2005
|
tom 47
|
nr 4
In order to describe the role of sedimentary processes for the phosphorus (P) cycle in the open Baltic Proper, P deposition and reflux were quantified for the predominately anoxic sediments of the Eastern Gotland Basin. The study is based on investigations of 53 surface sediment samples and pore water samples from 8 sediment cores. The average P deposition rate was estimated at 0.20 g±0.18 g m−2 yr−1, the fluctuation being due to variable bulk sediment deposition rates. P refluxes were estimated by applying Fick’s First Law of Diffusion. A fairly good positive correlation between sedimentary P deposition and P release was obtained. P release from sediments by diffusion exceeds net P deposition by a factor of 2. This suggests that 2/3 of the deposited gross P is recycled in the sediments and released back into the water column; only 1/3 remains in the sediment permanently. A budget calculation demonstrates that the released dissolved inorganic phosphorus (DIP) accounts for the observed increase in DIP concentrations in the deep water during periods of stagnation, which is noticeable even at the surface P concentrations. Under such conditions and with the present remediation conditions it is not possible to freely manage P concentrations in the water column on short time scales.
3
Artykuł dostępny w postaci pełnego tekstu - kliknij by otworzyć plik
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Synoptic changes in the deep rim current during stagnant hydrographic conditions in the Eastern Gotland Basin, Baltic Sea

100%
Hagen E., Feistel R.
Oceanologia
|
2007
|
tom 49
|
nr 2
Hydrographic and current measurements are analysed for stagnant deep-water conditions over the south-eastern topographic flank of the Eastern Gotland Basin (EGB) in April 2000. Results suggest a prevailing barotropic motion mode on a synoptic scale of several days. Deep along-slope volume transports derived from subsurface current meter moorings are compared with those of the baroclinic fraction of geostrophic motions crossing the plane of a hydrographic section. This was aligned perpendicular to deep isobaths and was repeated 40 times with a time step of six hours. Changes in regional winds produced a quasi-ten day cycle in the filling level of the Baltic Proper. Associated wave-like fluctuations of the mass field propagated cyclonically with a velocity of about 0.04 m s−1 around the deep basin’s rim. It is concluded that associated changes in deep volume transports result mainly from barotropically governed advection processes and that those of the baroclinic component of geostrophic currents provide a qualitatively and quantitatively quite inaccurate description of related transport fluctuations on a daily scale.
4
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Evidence for a warm water inflow into the Baltic Proper in summer 2003

84%
Feistel R., Nausch G., Heene T., Piechura J., Hagen E.
Oceanologia
|
2004
|
tom 46
|
nr 4
The exceptional warm water inflow into the Baltic Sea in summer 2002, which preceded the major Baltic inflow of January 2003, was surprisingly repeated in modified form in summer 2003. Its warm waters even replaced the renewed, cold inflow waters in the eastern Gotland Basin and commenced another warm period in its deep layers, where the previous one had lasted from 1997 to 2003. Details of the temporal and spatial behaviour of this new baroclinic inflow are presented from various measurements carried out from the Kiel Bight up to Gotland, covering the Darss Sill, the Arkona, Bornholm, Gdańsk Basins and the Słupsk Channel, focused mainly on the time period between July 2003 and July 2004. Hypothetically, the repetition of these exceptional warm inflow events could be regarded as a possible regional indicator for global climatic change.
5
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Environmental changes in the central Baltic Sea during the past 1000 years: inferences from sedimentary records, hydrography and climate

67%
Leipe T., Dippner J. W., Hille S., Voss M., Christiansen C., Bartholdy J.
Oceanologia
|
2008
|
tom 50
|
nr 1
23-41
Short sediment cores from the eastern Gotland Basin were investigated using a multi-proxy approach in order to reconstruct the environmental conditions of the area during the past 1000 years. Sediment data and facies were discussed in relation to hydrographic features (salinity, oxygen) and climate change. During the medieval warm period (MWP), from about 900 to 1250 AD, the hydrographic and environmental conditions were similar to those of the present time (modern warm period, since about 1850): a temporally stable halocline, caused by regular saline water inflows from the North Sea, prevents vertical mixing and leads to bottom water anoxia and the deposition of laminated, organic-rich sapropels. During the period from about 1250 to 1850, referred to as the cold phase (including the Little Ice Age), the environmental conditions of the central Baltic Sea were distinctly different: the lower salinity, resulting from reduced North Sea water inflows, allowed vertical convection of the water column and long-term stable ventilation of the sea bed (oxic stage). Both the productivity of the planktonic ecosystem as well as the preservation of organic matter in the sediments improved during the warm periods. The anthropogenic impact can be identified within the recent laminated sequence by a temporal reconstruction of pollutant deposition. Our findings imply a climate-change driven shift in the environmental conditions and the ecosystem of the Baltic from the north to the south and back to the north.
6

Carotenoid pigments in Baltic Sea sediments

67%
Lotocka M.
Oceanologia
|
1998
|
tom 40
|
nr 1
7

Macrozoobenthos of the Gdansk, Gotland and Bornholm Basins in 1978-1993

67%
Osowiecki A., Warzocha J.
Oceanological Studies
|
1996
|
tom 25
|
nr 1-2
8

The regional characteristics of the Gdansk Basin

51%
Andrulewicz E.
Oceanological Studies
|
1996
|
tom 25
|
nr 1-2
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