The influence of Elbe river water on the Wadden Sea of Sylt (German Bight, North Sea)

1980 ◽  
Vol 33 (2) ◽  
pp. 43-52 ◽  
Author(s):  
Wolfgang Hickel
1991 ◽  
Vol 24 (10) ◽  
pp. 77-85 ◽  
Author(s):  
J. Klamer ◽  
R. W. P. M. Laane ◽  
J. M. Marquenie

From literature data it is calculated that on an annual basis, 11 to 17 tonnes of PCBs enter the North Sea. Largest sources are the Atlantic Ocean and the atmosphere: together they account for 60-79% of the total input. Sources with greatest impact are the rivers, sewers and sludge. Highest concentrations are found close to the Dutch shore and in the German Bight. The PCB levels result in adverse effects on the seal population in the Wadden Sea. Of the total world PCB production, at least 57% is still in use and their future dispersal into the oceans cannot easily be controlled. If the increase in ocean PCB concentration continues, it may ultimately result in the extinction of fish-eating marine mammals.


2007 ◽  
Vol 42 (3) ◽  
pp. 271-288 ◽  
Author(s):  
Mona Hoppenrath ◽  
Bank Beszteri ◽  
Gerhard Drebes ◽  
Hannelore Halliger ◽  
Justus E. E. Van Beusekom ◽  
...  

1986 ◽  
Vol 23 (2) ◽  
pp. 171-182 ◽  
Author(s):  
T. Weisse ◽  
N. Grimm ◽  
W. Hickel ◽  
P. Martens

2020 ◽  
Vol 17 (16) ◽  
pp. 4223-4245
Author(s):  
Fabian Schwichtenberg ◽  
Johannes Pätsch ◽  
Michael Ernst Böttcher ◽  
Helmuth Thomas ◽  
Vera Winde ◽  
...  

Abstract. The coastal ocean is strongly affected by ocean acidification because of its shallow water depths, low volume, and the closeness to terrestrial dynamics. Earlier observations of dissolved inorganic carbon (DIC) and total alkalinity (TA) in the southern part of the North Sea, a northwest European shelf sea, revealed lower acidification effects than expected. It has been assumed that anaerobic degradation and subsequent TA release in the adjacent back-barrier tidal areas (Wadden Sea) in summertime is responsible for this phenomenon. In this study the exchange rates of TA and DIC between the Wadden Sea tidal basins and the North Sea and the consequences for the carbonate system in the German Bight are estimated using a 3D ecosystem model. The aim of this study is to differentiate the various sources contributing to observed high summer TA in the southern North Sea. Measured TA and DIC in the Wadden Sea are considered as model boundary conditions. This procedure acknowledges the dynamic behaviour of the Wadden Sea as an area of effective production and decomposition of organic material. According to the modelling results, 39 Gmol TA yr−1 were exported from the Wadden Sea into the North Sea, which is less than a previous estimate but within a comparable range. The interannual variabilities in TA and DIC, mainly driven by hydrodynamic conditions, were examined for the years 2001–2009. Dynamics in the carbonate system are found to be related to specific weather conditions. The results suggest that the Wadden Sea is an important driver for the carbonate system in the southern North Sea. On average 41 % of TA inventory changes in the German Bight were caused by riverine input, 37 % by net transport from adjacent North Sea sectors, 16 % by Wadden Sea export, and 6 % were caused by internal net production of TA. The dominant role of river input for the TA inventory disappears when focusing on TA concentration changes due to the corresponding freshwater fluxes diluting the marine TA concentrations. The ratio of exported TA versus DIC reflects the dominant underlying biogeochemical processes in the Wadden Sea. Whereas aerobic degradation of organic matter played a key role in the North Frisian Wadden Sea during all seasons of the year, anaerobic degradation of organic matter dominated in the East Frisian Wadden Sea. Despite the scarcity of high-resolution field data, it is shown that anaerobic degradation in the Wadden Sea is one of the main contributors of elevated summer TA values in the southern North Sea.


2020 ◽  
Author(s):  
Fabian Schwichtenberg ◽  
Johannes Pätsch ◽  
Michael Ernst Böttcher ◽  
Helmuth Thomas ◽  
Vera Winde ◽  
...  

Abstract. The coastal ocean is strongly affected by ocean acidification because it is shallow and has a low volume. Earlier observations of dissolved inorganic carbon (DIC) and total alkalinity (TA) in the southern part of the North Sea and the German Bight, a Northwest-European shelf sea, have revealed lower acidification effects than expected. It has been assumed that anaerobic degradation and subsequent TA release in the adjacent tidal areas (Wadden Sea) in summer time is responsible for this phenomenon. In this study the exchange rates of TA and DIC between the Wadden Sea and the North Sea and the consequences for the carbonate system in the German Bight are estimated using a 3-D ecosystem model. Observed TA and DIC sources in the Wadden Sea were considered as boundary conditions. This procedure is based on the dynamic behaviour of the Wadden Sea as an area of effective production and decomposition of organic material. In addition, modelled tidal water mass exchange was used to transport material between the open North Sea and the Wadden Sea. In the model, 39 Gmol TA yr−1 were exported from the Wadden Sea into the North Sea, which is lower than a previous estimate, but within a comparable range. Furthermore, the interannual variabilities of TA and DIC concentrations, which were mainly driven by hydrodynamic conditions, were examined for the years 2001–2009. Variability in the carbonate system of the German Bight is related to weather in that the occurrence of weak meteorological blocking situations leads to enhanced accumulation of TA there. The results suggest that the Wadden Sea is an important driver of the carbonate system variability in the southern North Sea. According to the model results, on average 63 % of all TA mass changes in the German Bight were caused by net transport, 25 % by Wadden Sea export, 9 % were caused by the internal production of TA and 3 % caused by effective TA river loads (i.e. river load including freshwater dilution). The ratio of exported TA and DIC reflects the dominant underlying biogeochemical processes in the different Wadden Sea areas. Aerobic degradation of organic matter plays a key role in the North Frisian Wadden Sea during all seasons of the year. In the East Frisian Wadden Sea anaerobic degradation of organic matter dominated.


2019 ◽  
Vol 625 ◽  
pp. 41-52 ◽  
Author(s):  
D Martínez-Alarcón ◽  
R Saborowski ◽  
E Melis ◽  
W Hagen

1997 ◽  
Vol 25 (2) ◽  
pp. 71-78 ◽  
Author(s):  
U. Ludwig ◽  
V. Neumann ◽  
T. Grischek ◽  
W. Nestler
Keyword(s):  

1997 ◽  
Vol 34 (6) ◽  
pp. 375-381 ◽  
Author(s):  
G. Radach ◽  
K. Heyer

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