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Dead zones are spreading in coastal areas of the Baltic Sea

For the first time, the oxygen situation in the whole Baltic Sea coast area was mapped. An international team of scientists report that oxygen has decreased in coastal areas of the Baltic Sea creating dead zones with a lack of oxygen.

Daniel Conley, together with other researchers examined the oxygen levels in coastal areas in all countries around the Baltic Sea. The study is published in the latest issue of the journal Environmental Science & Technology, and shows that the incidence of stems with a lack of oxygen is greater than ever. Moreover, they show that the number of places with hypoxia has increased over time. The main funder of the study is the Swedish private foundation Baltic Sea 2020.

“While we have known that deeper areas of the Baltic Sea have a lack of oxygen, we were surprised to find the same dismal results in so many areas along the coast” said Dr. Daniel Conley. _“The lack of oxygen leads to the death of organisms that live on the bottom and endangers the role of the coastal zone as a nursery area for fish.”

Sufficient oxygen in bottom waters is necessary for a healthy and well-functioning ecosystem with less algal blooms in the water. Scientists attribute the increase in hypoxic areas to elevated nutrient levels from the use of fertilizers, large animal farms with intensive livestock production, the burning of fossil fuels, and effluents from municipal wastewater treatment plants.

“Politicians from around the Baltic Sea must immediately implement the national reductions for nutrients that have been agreed upon in the HELCOM Baltic Sea Action Plan. If actions are postponed further, the situation in the Baltic Sea will continue to worsen,” Daniel Conley continues.

"The study shows how important it is to continue to work for a reduced leaching of nutrients from land. We are focusing right now on the improved handling of manure from large livestock farms so that in future they do not leak nutrients in the same high level as today," said Conrad Stralka, Executive Director Baltic Sea 2020.

For more information please contact
Daniel Conley, +46 707 49 43 41,

Daniel Conley is a Professor at the Department of Earth and Ecosystem Sciences (Institutionen för geo- och ekosystemvetenskaper) at Lund University. His research focuses on how human activities have changed nutrient inputs into the Baltic Sea and the responses of marine ecosystems to changes in human impact and climate.

Read the scientific article in Environmental Science and Technology here

Learn more about the project on the Baltic Sea 2020s website by cklicking here