Lövgrund is an island close to my mind because of the study that Celsius, a well known Swedish scientist for its heat scale, conducted regarding the level of the sea in the Baltic which appeared to be lowering along the centuries. In the mid 1700's, Celsius was asked to measure the rate of decrease of the water in the Baltic sea. He studied it in a couple of islands and Lövgrung is one of them.
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| Lövgrund island |
What he found was astonishing...
Celsius was commissioned to study the rate of decrease of the water sea level in the Baltic sea in the mid 17 hundreds. This had been a long issue in Sweden with villages having to move location to remain along the sea shore. Celsius decided to look at rocks that had been documented to host seals, and therefore have a value for seal hunters. Seals love to get on rocks to bask under the sun, but given their mass, they can only access rocks that are flat and very close to the water level. Going along the shore of Sweden, he documented such seal rocks and questioned the local population about how long these rocks were used by seals. By analysing these data, he could figure out a rough rate of decrease, which he estimated to be 1.4 cm per year. This was a bit overestimated as the rate of decrease is between 0.8 cm and 1 cm along the sea of Bothnia.
The picture below is taken from the Gästhamn in Lövgrund. In the centre, on the other side of the bay is the "Celsius" stone.
If you enlarge the below picture, you can sea where the water level was in 1731, 1.65 meters higher than today, and where it was in 1831 and 1931. The stone is getting on the shore nowadays, and there has been at least two centuries since the seals have deserted it.
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| Celsius stone, with marks for the sea level in 1731, 1831 and 1931... |
Below is the stone with annotations from the marks found on it. The distance from the 1731 and the 1831 marks is 78 cm, corresponding to a rate of change of 7.8 mm, close to the current estimations. However, the mark between 1831 and 1931 is close to 10 cm less than the previous 100 years, questioning whether the rate of sea level decrease is changing over the years. However, thinking twice, it is known that the level of the sea in the Baltic is dependant upon other factors, in particular related to atmospheric pressure and strength and direction of the winds in the previous weeks. The difference due to these additional factors can account for several dozen centimetres, and therefore could explain that marks made 100 years apart may have been affected by these factors.
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| Annotated Celsius stone |
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| Feet in the water, while it lasts... |
The picture below shows the view from the Celsius stone, representing pretty much what the seals were watching when on the stone. Except that most of the land on the other side of the bay was by then under water...
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| View of there bay, from the stone |
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| Belisama on one of the two SXK buoys in the Lövgrund bay |
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| Pebble beach typical from the area |
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| Raised beaches, resulting of isostatic, postglacial rebound. |
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| Angry birds defending their offspring |
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| Stéphane on the gästhamn jetty, with the stone in background. |
Besides the Celsius rock, Lövgrund village is worth a visit. The coast is marked with private signs almost everywhere, so we landed outside of the village along the pebble beach. But the people were very nice and welcomed us to go around freely, opening even the chapel for us to visit.
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| Lövgrund chapel |
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| Inside the chapel |
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| A votive sturgeon in the chapel |
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| A celsius thermometer and a Toricelli barometer in the church |
Very interesting! I just googled Celsius and Lövgrundet, and I found this post on your blog. I am studying Geography with Stockholm University. This was a very interesting read, and it is amazing to see the difference in sea-level from 1731 to 1831 to 1931 marked on the rock! Thanks!
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