NEW METHOD TO ANALYZE HOW AND WHY DEAD ZONES DEVELOP
The research team has, as part of their research in the BONUS-project HYPER (Hypoxia mitigation for Baltic Sea ecosystem restoration) and the HELCOM-project TARGREV developed a new method to analyze how these large dead zones develop and what the underlying causes are.
By analyzing the different processes that affect oxygen concentrations in bottom waters, the team has reconstructed oxygen and stratification conditions, and has been able to separate the effects of climate, saltwater inflows and nutrients.
The study, "Deoxygenation of the Baltic Sea during the last century" shows that nutrient inputs are the primary cause of today’s severe hypoxia situation. In addition, there are indications that higher deep-water temperatures in recent years may have had an addition effect.
HUMAN DRIVERS BEHIND THE INCREASE IN DEAD ZONES
The study highlights that although climate warming plays an important role in increasing ocean deoxygenation, anthropogenic nutrient discharges are the primary driving factor creating widespread hypoxic conditions in the Baltic Sea.
These increased nutrient levels can be attributed to the use of fertilizers, large animal farms, the burning of fossil fuels, and effluents from municipal wastewater treatment plants.
NEED FOR IMMEDIATE NUTRIENT REDUCTIONS THROUGH IMPLEMENTING THE BSAP
To be able to halt the increase of dead zones nutrient reductions are needed and the researchers call for immediate implementation of the HELCOM Baltic Sea Action Plan (BSAP) and the national reductions that the Baltic Sea countries have agreed upon.
If actions are postponed further, the research team fears that the situation will continue to worsen, not least under future climate changes.
This could have significant and devastating effects on the Baltic Sea ecosystem at all trophic levels, influencing benthic communities, biodiversity and the ecosystem services provided.
READ MORE ABOUT THE STUDY
THE STUDY IN THE MEDIA
The study has been mentioned in a wide range of international media and below are some examples for our international audience. If you are interested in more information, please contact BNI's communication officer Marmar Nekoro.
Germany, the article was featured more than 120 times (!), including in:
Poland, e.g. Interia and RMF24
Finland: e.g. Vasabladet and Österbottens Tidning
Italy, e.g. Article in La Stampa and in freenewspos.com
USA, e.g. Science Daily and some examples from China, Australia, Austria, UKand Switzerland.
France - a feature in the June issue of the French science magazine La Recherche (pdf, 1.6 MB)