SW22 Visit to Baltic Sea science center

Baltic Sea is special but why? It s à part of the ocean … where there are brackish and salt water. Life began in ocean and there are many species. But Stockholm is between the fresh water and marine oceanic. So species are low at 5-8%. Blue musles are very small and can t grow up… fresh water from rivers is up and saltier water is down in the sea. So the deeper places have low or none oxygen.  

We had presentation of different species that we can find: gelded fish.

Lot of deep places in the Baltic Sea (459 meters maximum). If We make a average it s 6 meters deep. 9 countries are connected with that sea. An experience was done about sea water and measure salinity … to illustrate the deep part and cost, we taste salt water in flow and see the different of density with coloured water … oxygen arrives in the deeper places. It is one of the world's busiest seas. For thousands of years, people have depended on the sea for their livelihoods, as sea routes and battlefields - and as graves. Often, boats and ships arrive safely in port. But not always. It is home to a unique cultural heritage. Thousands of shipwrecks and other remains rest on the bottom of the sea. The wooden wrecks remain thanks to the voracious shipworm, which doesn't thrive in the sea's cold, brackish waters.

Fish like eel and salmon migrate between salt- and freshwater during their lifetime. The salmon hatches in freshwater. After a few years they swim out into the sea to grow bigger. As adults they swim back into

rivers to reproduce. The eel is born in saltwater in the Sargasso Sea across the Atlantic Ocean. They swim all the way to Europe to grow bigger. Some swim into the Baltic Sea and continue into rivers. When it is time to reproduce, they return to the Sargasso Sea. There are almost no seasonal changes in deep water. The temperature is constantly low.

The guide explained why eyes of the flatfish are placed on top pf its head? As a fry, the flatfish looks like other fish with one eye on each side. After a short time one eye moves so that bott) eyes end up on the same side. The flatfish lives the rest of its life on one side with both eyes facing up.

The Baltic Sea is considered like a green sea full of plankton and particles. These absorb some of the wavelengths of the sunlight. The remaining light that we see is greenish. In seas with less nutrients and plankton the water looks bluer.

The temperature changes over the year. It is warm in the summer and cold enough for ice to form in the winter. Rain and snow bring freshwater and nutrients from land, making the water here less saline than out at sea. Many of the species here are also found in lakes.

Students/ teachers had a lot of interesting informations that they never heard before with a interesting guid