Storm Johannes pushed oxygen-free water from 90 metres deep onto the Baltic coast
A storm named Johannes, which hit Estonia late last year, lifted oxygen-free water from about 90 metres deep in the Baltic Sea into coastal shallows. Scientists have documented this for the first time in the Baltic.
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Storm Johannes, which struck Estonia at the end of last year, caused a rare and dangerous phenomenon in the Baltic Sea. Water containing no oxygen rose from a depth of about 90 metres and flowed into coastal shallows. That water had remained in the deep sea for decades.
Why it is dangerous
The source describes the oxygen-free water as a death trap for coastal ecosystems. Organisms living in shallow areas are adapted to different conditions, so water lacking oxygen poses a threat to them. This is why the original outlet calls it “dead water”.
A first documented case
The source states that scientists had not previously documented such an event in the Baltic Sea. It shows that storms can do more than stir the surface: they can also trigger abrupt changes in deeper layers, which normally stay separate from the coast.
The source says the event was barely noticed, which underlines why monitoring the condition of the sea after storms matters. The available text gives no further detail on the extent of the impact on particular species or stretches of coastline.
