Henryk Świdziński Mofette near Muszyna

The Henryk Świdziński Mofette, on the border of Jastrzębik and Złockie near Muszyna, is the largest and most productive mofette in Poland. Gas that is 95% carbon dioxide bubbles up constantly from the bed of the Złocki stream. An area of about 25 m² releases roughly 10 m³ of gas per minute.

What is a mofette?

A mofette is a gas vent with a temperature below 100°C; here the gas rises from the stream bed together with mineralised water. Besides CO₂ it contains nitrogen (3.87%), methane (0.67%) and oxygen (0.21%). The carbon dioxide comes from great depths and saturates groundwater on its way up, creating the many carbonated springs in the area, such as St Luke's spring. The rusty colour of the water comes from a deposit formed with the help of iron bacteria.

Bulgotka, Dychawka and the "breath of the earth"

The mofette was discovered in 1938 by the geologist Henryk Świdziński, after whom it is named. It is a protected natural monument. Muszyna municipality has installed a footbridge, steps and information boards, and two gas outlets have been enclosed: Bulgotka ("the Bubbler") in the stream bed and Dychawka ("the Wheezer"), a little further from the water. The latter makes a sound known as the "breath of the earth".

Did you know?

Carbon dioxide is heavier than air and collects near the ground in still weather. Insects and birds die above the mofette, and there have even been cases of sheep collapsing. In the past gas building up in leaky cellars plagued the people of Jastrzębik – one fatal suffocation is on record. There is also a dry gas exhalation in the area that leaves snow-free patches on the fields in winter.

Tripto tips

The mofette is right by the road from Jastrzębik to Złockie, a few kilometres from central Muszyna. Admission is free, and 15–30 minutes is enough. Stay on the footbridge, do not lean low over the vents, and keep an eye on children and dogs, especially on windless days. The municipality has planned new walkways, so check before you go whether any works are under way.