Our directory of things of interest

University Directory

Baltic Sea oxygen depletion worsening

  • Written by  Olivia Edward
  • Published in Oceans
Baltic Sea oxygen depletion worsening NASA
01 May
2014
Oxygen depletion in the Baltic Sea is ten times worse now than it was 100 years ago, the result of nutrient inflows from the land

The Baltic Sea is extremely stratified, with a layer of relatively fresh water sitting on top of a layer of denser, saltier, poorly oxygenated water. This stratification limits the amount of mixing, which is necessary for the transfer of oxygen to the water at the bottom of the sea. Oxygen levels in this lower layer are often so low that it causes the death of animals and plants that live on the seabed.

For a new study published in the Proceedings of the National Academy of Sciences, an international team of researchers analysed 115 year’s worth of data for water temperature, oxygen content and salinity in the Baltic. They found that over that period, the areas of oxygen depletion has increased from about 5,000 square kilometres to about 60,000 square kilometres. ‘On the basis of this analysis, we can determine that the many nutrients from the land are the main cause of the widespread oxygen depletion,’ said the study’s lead author, Professor Jacob Carstensen of Aarhus University in Denmark.

The results also indicated that during the past 20 years, climate change has played a role in the Baltic’s oxygen depletion. As the sea’s water warms, it reduces the amount of oxygen it can hold, while also increasing oxygen consumption by the organisms living in the sea.

This story was published in the May 2014 edition of Geographical Magazine

Related items

NEVER MISS A STORY - Follow Geographical on Social

Want to stay up to date with breaking Geographical stories? Join the thousands following us on Twitter, Facebook and Instagram and stay informed about the world.

More articles in NATURE...

Climate

History is littered with examples of fungi helping to digest…

Geophoto

The streets of Philadelphia are home to a small and forgotten…

Geophoto

When photographer Matthew Maran first snapped a fox he had…

Wildlife

Coloradans have voted to reintroduce grey wolves to the state

Energy

Covid-19 provides an opportunity to re-assess the supply chains of…

Geophoto

Andrea DiCenzo is a photojournalist, who has covered conflicts for…

Oceans

Field observations of corals around the world reveal that not…

Climate

The Great Plains of the USA are once again getting…

Climate

Attempts to build a digital twin of the Earth could…

Oceans

Food systems will need to change as the global population…

Wildlife

Zoos do a lot more than welcome excited visitors; closures…

Oceans

 BluHope is back with a day of webinars to promote…

Wildlife

WildEast, a grassroots community initiative, is encouraging volunteers to commit…

Wildlife

With growing global awareness of the risks of hunting and…

Climate

Researchers have identified the extent of microplastic contamination throughout the…

Wildlife

The Thames Estuary has long been home to heavy industry,…

Wildlife

Whydahs and indigobirds, collectively known as the vidua finches, show…

Oceans

Whales sequester an enormous amount of carbon, making their protection…