Pollution of the Outer Oslofjord

1991 ◽  
Vol 24 (10) ◽  
pp. 321-322
Author(s):  
Kjell Baalsrud
Keyword(s):  
North Sea ◽  
General Circulation ◽  
Sea Water ◽  
Sewage Treatment ◽  
Circulation Pattern ◽  
Polluted Water ◽  
The North ◽  
Recreation Area ◽  
The North Sea ◽  
Sill Depth

The Outer Oslofjord has recently been subject to concern. 1. The Inner Oslofjord. Covers an area of 193 km2, is 160 m deep and is separated from the Outer Oslofjord by the narrow Drøbak sound with a sill depth of less than 20 metres. This part of the Oslofjord constitutes an enclosed body of sea water, sensitive to pollution, receiving sewage from approximately 650,000 inhabitants. In spite of modern sewage treatment, the fjord still suffers torn eutrophication problems resulting in reduced oxygen in the deep water, and areas of anoxic bottom water. The fjord is an important recreation area. 2. The Outer Oslofjord. Recent findings indicate that eutrophication is slowly increasing. An increasing eutrophication of the Outer Oslofjord wil also increase the need (and cost) of better sewage treatment in the Inner Oslofjord. 3. The North Sea. The quality of the water in the Oslofjord area is also dependent on the water it receives from the Skagerrak. The Skagerrak water will periodically receive polluted water from the southern North Sea and Kattegat. When these episodes coincide with water renewals between the Oslofjord and the Skagerrak, the fjord will receive polluted water from other countries. The Oslofjord water will in turn discharge into the Skagerrak, but due to the general circulation pattern, this will mainly influence the Norwegian south-east coast.

Variability patterns of the general circulation and sea water temperature in the North Sea

2015 ◽  
Vol 135 ◽  
pp. 91-112 ◽  
Author(s):  
M. Mathis ◽  
A. Elizalde ◽  
U. Mikolajewicz ◽  
T. Pohlmann
Keyword(s):  
Water Temperature ◽  
North Sea ◽  
General Circulation ◽  
Sea Water ◽  
The North ◽  
The North Sea

scholarly journals An ensemble study of extreme storm surge related water levels in the North Sea in a changing climate

Ocean Science ◽  
2009 ◽  
Vol 5 (3) ◽  
pp. 369-378 ◽  
Author(s):  
A. Sterl ◽  
H. van den Brink ◽  
H. de Vries ◽  
R. Haarsma ◽  
E. van Meijgaard
Keyword(s):  
North Sea ◽  
Climate Model ◽  
Sea Water ◽  
Global Climate ◽  
Global Climate Model ◽  
Storm Surges ◽  
Water Levels ◽  
The North ◽  
Extreme Storm ◽  
The North Sea

Abstract. The height of storm surges is extremely important for a low-lying country like The Netherlands. By law, part of the coastal defence system has to withstand a water level that on average occurs only once every 10 000 years. The question then arises whether and how climate change affects the heights of extreme storm surges. Published research points to only small changes. However, due to the limited amount of data available results are usually limited to relatively frequent extremes like the annual 99%-ile. We here report on results from a 17-member ensemble of North Sea water levels spaning the period 1950–2100. It was created by forcing a surge model of the North Sea with meteorological output from a state-of-the-art global climate model which has been driven by greenhouse gas emissions following the SRES A1b scenario. The large ensemble size enables us to calculate 10 000 year return water levels with a low statistical uncertainty. In the one model used in this study, we find no statistically significant change in the 10 000 year return values of surge heights along the Dutch during the 21st century. Also a higher sea level resulting from global warming does not impact the height of the storm surges. As a side effect of our simulations we also obtain results on the interplay between surge and tide.

Water circulation in the Firth of Forth, Scotland

1987 ◽  
Vol 93 (3-4) ◽  
pp. 273-284 ◽  
Author(s):  
P. P. G. Dyke
Keyword(s):  
General Circulation ◽  
Bottom Topography ◽  
Circulation Pattern ◽  
Theoretical Models ◽  
The North ◽  
Open Sea ◽  
River Outflow ◽  
The North Sea ◽  
Firth Of Forth ◽  
Wind Driven Currents

SynopsisThe Firth of Forth, in terms of physical oceanography, is part of the North Sea. The general circulation pattern in the firth must be regarded as largely speculative. There have been insufficient measurements of insufficient quality, and what evidence exists leads to the view that what circulation there is, is sluggish and varies from season to season and from year to year.A description is given of the three principal mechanisms that contribute to circulation. Tides, due initially to astronomical forces, manifest themselves in the Firth of Forth through the rise and fall of the adjacent open sea. This rise and fall, periodic in mid ocean, is no longer strictly so in the firth and neither are the tidal currents. The wind-driven currents in the sea are influenced by the earth's rotation. In the Firth of Forth, some of this influence is retained. Naturally, wind-driven currents are larger near the surface. Finally, when water of different densities meets, overturning causes convection currents. All of these effects are present to some extent in the Firth of Forth. In addition, specific account has to be taken of complicated coastal and bottom topography and river outflow. Some attempt to bring together these effects and available measurements is made in this paper. Lastly, several theoretical models are proposed which account for the magnitudes and directions of the observed steady circulation. Mathematical details are given in appendices.

scholarly journals Seasonal variations in the occurrence of Vibriovulnificusalong the Dutch coast

1994 ◽  
Vol 112 (2) ◽  
pp. 285-290 ◽  
Author(s):  
J. Veenstra ◽  
P. J. G. M. Rietra ◽  
J. M. Coster ◽  
E. Slaats ◽  
S. Dirks-Go
Keyword(s):  
Seasonal Variation ◽  
Water Temperature ◽  
North Sea ◽  
Seasonal Variations ◽  
Water Samples ◽  
Human Disease ◽  
Sea Water ◽  
Dutch Coast ◽  
The North ◽  
The North Sea

SUMMARYThe seasonal variation in the occurrence ofV. vulnificusin relation to water temperature and salinity was studied along the Dutch coast. In two consecutive yearsV. vulnificusstrains could be isolated in August when the water temperature was highest. The indole-positive strains isolated from North Sea water samples were identical to most strains isolated from human disease and from the environment. However, strains isolated from four of five patients living in countries around the North Sea were different from the North Sea isolates in that they were indole-negative and have a lower NaCl tolerance.

Annual and spatial variability in endo- and ectoparasite infections of North Sea cod (Gadus morhua Linnaeus, 1758) larvae, post-larvae and juveniles

2014 ◽  
Vol 59 (2) ◽  
Author(s):  
Foojan Mehrdana ◽  
Qusay Bahlool ◽  
Alf Skovgaard ◽  
Jesper Kuhn ◽  
Per Kania ◽  
...  
Keyword(s):  
Spatial Variability ◽  
North Sea ◽  
Gadus Morhua ◽  
Sea Water ◽  
Atlantic Cod ◽  
The North ◽  
Infection Pressure ◽  
High Prevalence ◽  
Atlantic Cod Larvae ◽  
The North Sea

AbstractA parasitological investigation was performed on a total of 5380 Atlantic cod larvae, post-larvae and small juveniles sampled from the North Sea during a period of five years. The copepod Caligus elongatus (Von Nordmann, 1832) and the nematode Hysterothylacium aduncum (Rudolphi, 1802) were found at a relatively high prevalence of infection (4.6% and 5.2%, respectively). The infection by both parasites showed annual and spatial variability. C. elongatus showed a higher prevalence in 1992 compared to the following years, whereas the prevalence of H. aduncum increased from 1992 to 2001.We observed a relation between parasite distribution and parameters such as latitude and water depth. Adult digeneans (Lecithaster gibbosus and Derogenes varicus) and larval cestodes were also found with lower infection rates. Since changes of infection levels coincided with increasing North Sea water temperature in the studied period, it is hypothesized that temperature may affect parasite population levels. However, it is likely that other environmental factors may contribute to the observed variations. Absence of infection intensities higher than one nematode per fish in small larvae and post-larvae suggests that host survival may be affected by a high infection pressure. The relatively high levels of infection in the younger stages of cod, and the annual/spatial variability of these infections should be considered in the understanding of the early life dynamics of the species.

scholarly journals Contribution of atmospheric circulation to recent off-shore sea-level variations in the Baltic Sea and the North Sea

2018 ◽  
Vol 9 (1) ◽  
pp. 69-90 ◽  
Author(s):  
Sitar Karabil ◽  
Eduardo Zorita ◽  
Birgit Hünicke
Keyword(s):  
Baltic Sea ◽  
Sea Level ◽  
North Sea ◽  
Circulation Pattern ◽  
Net Energy ◽  
The Baltic Sea ◽  
Sea Level Variability ◽  
The North ◽  
The North Sea ◽  
The Baltic

Abstract. The main purpose of this study is to quantify the contribution of atmospheric factors to recent off-shore sea-level variability in the Baltic Sea and the North Sea on interannual timescales. For this purpose, we statistically analysed sea-level records from tide gauges and satellite altimetry and several climatic data sets covering the last century. Previous studies had concluded that the North Atlantic Oscillation (NAO) is the main pattern of atmospheric variability affecting sea level in the Baltic Sea and the North Sea in wintertime. However, we identify a different atmospheric circulation pattern that is more closely connected to sea-level variability than the NAO. This circulation pattern displays a link to sea level that remains stable through the 20th century, in contrast to the much more variable link between sea level and the NAO. We denote this atmospheric variability mode as the Baltic Sea and North Sea Oscillation (BANOS) index. The sea-level pressure (SLP) BANOS pattern displays an SLP dipole with centres of action located over (5° W, 45° N) and (20° E, 70° N) and this is distinct from the standard NAO SLP pattern in wintertime. In summertime, the discrepancy between the SLP BANOS and NAO patterns becomes clearer, with centres of action of the former located over (30° E, 45° N) and (20° E, 60° N). This index has a stronger connection to off-shore sea-level variability in the study area than the NAO in wintertime for the period 1993–2013, explaining locally up to 90 % of the interannual sea-level variance in winter and up to 79 % in summer. The eastern part of the Gulf of Finland is the area where the BANOS index is most sensitive to sea level in wintertime, whereas the Gulf of Riga is the most sensitive region in summertime. In the North Sea region, the maximum sea-level sensitivity to the BANOS pattern is located in the German Bight for both winter and summer seasons. We investigated, and when possible quantified, the contribution of several physical mechanisms which may explain the link between the sea-level variability and the atmospheric pattern described by the BANOS index. These mechanisms include the inverse barometer effect (IBE), freshwater balance, net energy surface flux and wind-induced water transport. We found that the most important mechanism is the IBE in both wintertime and summertime. Assuming a complete equilibration of seasonal sea level to the SLP gradients over this region, the IBE can explain up to 88 % of the sea-level variability attributed to the BANOS index in wintertime and 34 % in summertime. The net energy flux at the surface is found to be an important factor for the variation of sea level, explaining 35 % of sea-level variance in wintertime and a very small amount in summer. The freshwater flux could only explain 27 % of the variability in summertime and a negligible part in winter. In contrast to the NAO, the direct wind forcing associated with the SLP BANOS pattern does not lead to transport of water from the North Sea into the Baltic Sea in wintertime.

scholarly journals Generalist hydrocarbon-degrading bacterial communities in the oil-polluted water column of the North Sea

2014 ◽  
Vol 8 (3) ◽  
pp. 434-447 ◽  
Author(s):  
Panagiota-Myrsini Chronopoulou ◽  
Gbemisola O. Sanni ◽  
Daniel I. Silas-Olu ◽  
Jan Roelof van der Meer ◽  
Kenneth N. Timmis ◽  
...  
Keyword(s):  
Water Column ◽  
North Sea ◽  
Bacterial Communities ◽  
Polluted Water ◽  
The North ◽  
The North Sea

The North Sea: an overview

1987 ◽  
Vol 316 (1181) ◽  
pp. 461-485 ◽  
Keyword(s):  
Trace Metals ◽  
Organic Compounds ◽  
North Sea ◽  
Human Activities ◽  
Sea Water ◽  
Sea Floor ◽  
Natural Systems ◽  
The North ◽  
The North Sea ◽  
Trace Constituents

An overview is given of the natural systems of the North Sea: water-circulation, topography and geology of the sea floor, sediment transport, influx of trace constituents (nutrients, trace metals, organic compounds), biological systems and their interrelations. The effects of pollution and other human activities are discussed as well as the difficulties in assessing them where they are obscured by natural changes.

Quantitative studies on the marine Phycomycetes between Fladenground and the mouth of the River Tay

1980 ◽  
Vol 78 (3-4) ◽  
pp. s131-s131
Author(s):  
S. Raghu Kumar
Keyword(s):  
Surface Water ◽  
North Sea ◽  
Sea Water ◽  
Seasonal Fluctuation ◽  
Fungal Population ◽  
The North ◽  
Quantitative Studies ◽  
The North Sea ◽  
Very High ◽  
High Seas

SynopsisQuantitative studies on marine Phycomycetes (thraustochytrids) were carried out at 6 stations between the Fladenground area of the North Sea and the mouth of the River Tay, between September 1975 and September 1976. Five samplings were made of the surface water and the sediment during this period. The number of fungi/litre sea water or sediment increased with the proximity to the mouth of the river compared to the high seas. The fungal population exhibited a seasonal fluctuation, a high number occurring in September and an extremely low number occurring in March. The sediments revealed a very high number of propagules/litre (up to 73,000) compared to the water (up to 384).

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