North Sea and Baltic Sea Meeting Phenomenon

Why don’t the Baltic and North Sea mix? This question has been puzzling scientists for a long time. Aside from being a natural phenomenon, the two seas that meet in the Atlantic Ocean are also mentioned in the Quaran. People used to think that Baltic and North Sea have a sharp boundary between them, but the latest evidence points at a different reason why North Sea and Baltic Sea don’t mix.

Abstract

The phenomenon of the water exchange between the Baltic and the North Sea attracted the attention of numerous scientists because their waters meet without mixing. Such thing is observed mainly because of the difference in density, but a range of other factors also plays a significant role in this perspective. Thus, it is critical to discuss the geography of the seas and make a detailed description of their hydrography. Except for that, the phenomenon can be considered from the religious point of view.

Baltic and North Sea: Introduction

When two or more bodies of water meet they mingle as there are no visible barriers that can prevent their mishmash. However, in some cases, this obvious process is not observed. Such ‘supernatural’ phenomenon is seen at Skagen, Denmark. The waves of the Baltic and North Seas clash into each other as if they are somehow separated.

The North Sea is a shipping lane of great significance for Europe, as it provides an opportunity to import products by water. This sea is connected to the Atlantic Ocean “via the English Channel and the Norwegian Sea and has a surface area of around 750,00sq km” (Lavery, 2013, p. 183). The Baltic Sea, in its turn is smaller and covers almost 400,000sq km (Hinkkanen & Kirby, 2000). The North Sea meets the Baltic Sea, but their waters never mingle, which results in the phenomenon that attracts the attention not only of the scientists but also the general public as its unique view is more than just picturesque. The waves of the North Sea are rather gusty, and its waters are dark. On the contrary, the Baltic Sea is known for its calm and clear waters. As a result, the place where they meet is vividly seen due to the sharp contrast between the waters of these seas. This phenomenon was thoroughly investigated, and the scientists came up to the conclusion that the seas do not mingle because of the differences in their waters.

Geography of North Sea and Baltic Sea

The area between the North and Baltic Seas consists of several basins. There are four of them, and each differs in its topography. The Baltic Sea is claimed to look like a riverbed, the waters of which underwent a long geologic history and had numerous names. The submergence or emergence of the region influenced the main characteristics of the waters. Post-glacial rebound is typical for the Baltic Sea because the land was affected by the weight of ice (Schwarzer, 2010). As a result, the sea becomes shallower, and its surface area diminishes. The geology of the seabed proves that the waters were extending slowly and made it slope. On the contrary, the waters of the North Sea varied greatly. For example, the appearance of the Western and Central Europe made it cut off from the English Channel for some period of time. The bottom of the Northern Sea consists of sand and gravel. The changes in the ice sheet also affected the condition of the sea and could have even made it dry. However, the situation altered and it started flooding the shelf of Europe (Zijl, Verlaan, & Gerritsen, 2013).

Descriptive Hydrography of the Area

Even though the Baltic and North Seas do not mingle, their waters exchange when varied waters of the Baltic Sea meet with the intensive but short in their duration waves of the North Sea. As a rule, the waves of the Baltic Sea are lower than those of the North one. The temperature of the sea is changeable because of the climate change, which causes sudden storms in connection with the wind peculiarities. The North Sea is rather cold, as it gains ocean current. Still, a small portion of the warm current from the English Channel comes to it also. As a result, tidal currents mix and create some kind of layers of water. Those that are on the surface and those that lie deep often differ in their directions: low salinity waters tend to move offshore while the rest of the sea moves inshore. The level of the water alters mainly in relation to the wind situation, which is not ordinary. In the majority of cases, tidal effects play more important role in the differences in the water level. Still, seasonal winds play a significant role in the alterations of the sea level even though it is not critical (+/- 0.5m).

The flow of the Baltic Sea is rather complex due to the difference in salinity. The waters mix very slowly and only in the area near to the surface. Such gradation is not so visible in the North Sea because it receives the majority of the Atlantic Ocean current, which minimalizes its connections with fresh waters. Of course, the salinity of the North Sea is not as high as it is in the ocean but it remains rather palpable. It can be explained by the fact that the outflowing waters mingle with it and affect the sea. In the areas where the North Sea is rather shallow, the saline waters are gathered near to the surface, which provides an opportunity for the waters to mingle and mix. It can be observed in the south and west of the Kattegat, for example. As a result, the Baltic Sea shares its waters and is not turning into the freshwater lake. It might have happened because its drainage basin is much bigger that the whole area of the sea but, fortunately, it did not happen. The salinity of the Baltic Sea is not constant and tends to vary with the course of time, but it is definitely inferior to the North Sea (Hinkkanen & Kirby, 2000).

The mix of the fresh and salt water in the Baltic Sea causes a gradient of salinity that depends on its depth and is connected with the gradient of temperature. They limit the species of plants and animals that leave within the territory of the sea. The water that is extremely saline in comparison to the rest of the sea can be found near the bottom at the north. It builds a kind of invisible barrier that prevents the exchange of oxygen and nutrients, which causes the creation of two different environments within one body of water.

In this way, the difference in the chemical composition of waters, known as a halocline, occurs and prevents the seas from mingling (Kuzmina, Zhurbas, Rudels, Stipa, & Paka, 2008). The most salt water tends to be near the bottom of the seas, which minimalizes the counter-clockwise mishmash. The difference between the seas is constantly supported by the fresh water that is coming to the Baltic Sea from the rivers of North Europe and the discrepancy of precipitation less evaporation.

The amount of oxygen in the water is also critical for mingling. Its presence below the surface of the Baltic Sea is hardly observed, which proves its severe lack. That is why the inflows from the North Sea are critical for the Baltic Sea, as they bring salty water and oxygen to its deeps. As a result, the ecosystem of the Baltic Sea improves (Almroth & Skogen, 2010). Such inflows used to happen every five years but now they are twice rarer. Except for that, the layers of water near the surface are replaced more often than those in the deepest parts. As a result, “only 20% of the water coming from the North Sea is so saline and heavy that it can sink below 130 meters, and a far smaller proportion is so heavy that it can sink right to the bottom of the depths, and force out the old bottom waters” (Hinkkanen & Kirby, 2000, p. 11).

Religious Approach

Today the mixing of waters is also discussed from the religious perspective. Depending on their beliefs people see the different causes of one and the same phenomenon. Thus, while scientists just claim that the seas that meet but not mingle have different density due to the alterations in fresh and salt water and temperature, religious people search for detailed explanations in the God’s words.

More than a thousand years ago the answer to such phenomenon was also found in Quran: “He has granted freedom to the two great seas to meet. Yet there is a barrier in between which they cannot delete” (Quran 55:19; 55:20).

It was even mentioned that the seas never mingle because of the difference in their waters. According to it, there is a barrier between the waters of two seas: “And He it is Who has made two seas to flow freely, the one sweet that subdues thirst by its sweetness, and the other salt that burns by its saltness; and between the two He has made a barrier and inviolable obstruction” (Quran, 25:53).

Thus, it should be underlined that the difference between salt and fresh water that is discussed by all scientists is also mentioned in the religious source. Of course, people are not able to see the barrier that is discussed, and it even cannot be called a ‘barrier’ if it is considered from the scientific point of view but the ways of treating this phenomenon from different approaches seem to have much in common (Yahya, 2013). It proves that the language of scientific truths is known to religion. The meeting of the Baltic and North Seas perfectly meets the explanation of the phenomenon in Quran. Considering both approaches, it can be said that they are alike, which proves their authenticity.

Conclusion

Taking everything mentioned into consideration, it can be concluded that the reason the Baltic Sea and the Northern Sea meet but their waters do not mingle is the difference in their density, which is connected with the salinity. This chemical difference is known as a halocline. The North Sea has more saline water as it comes from the Danish Straits while the Baltic Sea has fresh and clean water that comes from the drainage basin. From time to time, the temperature of the bodies of water alters, which causes surface mixing. Still, it happens only in particular regions where the seas are rather shallow, so they remain mostly separate.

References

Almroth, E., Skogen, M. (2010). A North Sea and Baltic Sea model ensemble eutrophication assessment. Ambio, 39(1), 59-69.

Hinkkanen, M., & Kirby, D. (2000). The Baltic and the North Seas. New York, NY: Routledge.

Kuzmina, N., Zhurbas, V., Rudels, B., Stipa, T., & Paka, V. (2008). Role of eddies and intrusions in the exchange processes in the Baltic halocline. Oceanology, 48(2), 149-158.

Lavery, B. (2013). The conquest of the ocean. London, UK: Penguin.

Quaran. (2011). 

Schwarzer, K. (2010). Aggregate resources and extraction in the Baltic Sea. Journal of Coastal Research, Sl(51), 165-172.

Yahya, H. (2013). Quran on mixing of seas and rivers. Web. 

Zijl, F., Verlaan, M., & Gerritsen, H. (2013). Improved water-level forecasting for the Northwest European Shelf and North Sea through direct modeling of tide, surge and non-linear interaction. Ocean Dynamics, 63(7), 823-847.