03 Suolijärvi nature trail information board

Is Lake Suolijärvi eutrophic?

Suolijärvi is a clear and medium nutrient lake, and thus represents a common lake type in Finland. The deepest point of the lake is nine metres deep.

In order to protect the lake, water quality is regularly monitored for nutrients, particularly nitrogen and phosphorus. An increase in these can lead to eutrophication, i.e. a significant increase in vegetation, resulting in a wide range of changes that can affect the well-being of the existing biota.

The resident loon is a fine metric of water quality, as it dislikes lakes that are too eutrophic. Can you guess why? The area around the sign, Sonninottanlahti, is mildly eutrophic, as you can see from the vegetation – such as lake grass – that has spread along the water's edge over time.

The biota in the lake includes plankton, aquatic plants, insects, fish, and many water birds, whose food web you can guess from the picture. 

Which organisms absorb the sun's rays? 

Who eats whom?

Like a fish in water 

Fish, like all vertebrates, have all five senses familiar to humans: sight, hearing, taste, smell and touch. Fish feel heat, pressure and pain. 

In addition, fish have a ribbed sense, which is similar to a combination of hearing and touch; this is used to sense vibrations in the water and is thought to have evolved the inner ear in many terrestrial animals. Other adaptations to life underwater include gills, which allow fish to filter oxygen from the water they swallow.

What kind of adaptations does the fictional fish in the picture have to aquatic life?