Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Oxygen arrived at the bottom of the Central Baltic Sea

05.03.2015

Two and a half months after oxygen rich North Sea water entered the Baltic Sea, IOW scientists measure its effect in the Gotland Basin.

The Eastern Gotland Basin in the centre of the Baltic Sea is the largest and second deepest of the Baltic Sea basins. Here, the water masses and any marine life below 90 m water depth nearly constantly suffer from oxygen depletion and toxic hydrogen sulfide.


Comparative maps from areas with oxygen depletion and hydrogen sulfide occurrence in the near-bottom water layer of the Baltic Sea at the time of A- November 2014 (stagnation) an B-February 2015 (salt water inflow). At selected stations, oxygen and hydrogen sulfide concentrations are depicted in bar chart. The 70 m isobath serves for orientation and illustration of the deeper basins in the central Baltic.

Source: IOW

For this reason, these regions are often referred to as “dead zone”. Physical Oceanographers from the Leibniz Institute for Baltic Sea Research in Rostock Warnemünde now measured oxygen in the bottom water. This proves their earlier presumptions that the amount of inflowing water masses was large enough and its salt content and density sufficient to let them pass the submarine sills and reach the Baltic Proper.

The inflow of December 2014 was the largest event since 1951 and the third largest since the beginning of oceanographic measurements in the Baltic.

The scientific crew with Dr. Lars Umlauf as chief scientist on board of r/v ALKOR is on its way through the central Baltic Sea from the 26th of February to 11th of March 2015.

Contact:

Dr. Michael Naumann, Department Physical Oceanography and Instrumentation, IOW (phone: +49 381 5197 267, Email: michael.naumann@io-warnemuende.de)

Dr. Barbara Hentzsch, Public Relation, IOW, phone: +49 381 5197 102, Email: barbara.hentzsch@io-warnemuende.de)

Background information: salt water inflows
The water body of the Baltic Sea is permanently stratified with brackish surface water fed by the constant freshwater discharge of numerous rivers. This surface layer is in constant exchange with the atmosphere. It is well provided with oxygen by wind mixing, temperature-induced convection processes and the biological production. From a depth of approximately 70 m on, in areas which are no longer influenced by wind mixing, the Baltic Sea shows its close connection to the North Sea: it is here that the salty North Sea water concentrates which periodically flows into the Baltic Sea via the Danish Belt Sea, Being saltier than the Baltic Sea water, it is also heavier, thus it is flowing along the bottom of the Baltic Sea into the deep basins.

Both water bodies do not mix but to a minor degree which causes a permanent stratification. Solid particles like dead organic matter can easily pass this boundary whereas gases dissolved in the water are hold back efficiently. The oxygen content of the deep water therefore constantly decreases as the oxygen is consumed during the decomposition of the deposited organic particles. When the oxygen is entirely depleted, toxic hydrogen sulfide forms. An improvement of this state can only be reached by the lateral supply with large amounts of North Sea water which has been in contact with the atmosphere and therefore is rich in oxygen.

Submarine sills in the Western Baltic Sea hamper this horizontal water exchange. Only under specific meteorological conditions, the salt water can pass these natural impediments to supply the eastern/central parts of the Baltic Sea with oxygen. These sills are the so called Darß Sill, an extended sandy plain between the Danish Island of Moen and the peninsula of Fischland-Darß-Zingst with water depths of 18 – 19 m, and the Drogden Sill being positioned in the Oere Sound between the Danish island Zealand and the Swedish mainland with water depths of only 8–9 m.

Since 2003, no major salt water inflow has occured, which has led to the fact that in the deep areas of the central Baltic Sea (>90 m) all oxygen has been consumed and an increased formation of hydrogen sulfide went on. Thus, the biological living conditions for higher organisms have strongly been limited in these areas, which therefore were often referred to as “dead zones” in the media .

The IOW is a member of the Leibniz Association to which 89 research institutes and scientific infrastructure facilities for research currently belong. The focus of the Leibniz Institutes ranges from Natural, Engineering and Environmental Science to Economic, Social, and Space Sciences and to the humanities. The institutes are jointly financed at the state and national levels. The Leibniz Institutes employ a total of 17.200 people, of whom 8.200 are scientists, of which 3.300 are junior scientists. The total budget of the Institutes is more than 1.5 billion Euros. Third-party funds amount to approximately € 330 million per year. www.leibniz-gemeinschaft.de

Weitere Informationen:

http://www.io-warnemuende.de/baltic-inflow-of-december-2014.html - More information on the inflow event of December 2014
http://www.io-warnemuende.de/baltic-inflow-of-december-2014-computer-simulation.... - Computer simulation showing the bottom-near distribution of the inflow water.

Dr. Barbara Hentzsch | idw - Informationsdienst Wissenschaft

Further reports about: Atmosphere Baltic Sea IOW Leibniz-Institut Ostseeforschung Oxygen Warnemünde sulfide toxic

More articles from Earth Sciences:

nachricht Clear as mud: Desiccation cracks help reveal the shape of water on Mars
20.04.2018 | Geological Society of America

nachricht Hurricane Harvey: Dutch-Texan research shows most fatalities occurred outside flood zones
19.04.2018 | European Geosciences Union

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Spider silk key to new bone-fixing composite

University of Connecticut researchers have created a biodegradable composite made of silk fibers that can be used to repair broken load-bearing bones without the complications sometimes presented by other materials.

Repairing major load-bearing bones such as those in the leg can be a long and uncomfortable process.

Im Focus: Writing and deleting magnets with lasers

Study published in the journal ACS Applied Materials & Interfaces is the outcome of an international effort that included teams from Dresden and Berlin in Germany, and the US.

Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...

Im Focus: Gamma-ray flashes from plasma filaments

Novel highly efficient and brilliant gamma-ray source: Based on model calculations, physicists of the Max PIanck Institute for Nuclear Physics in Heidelberg propose a novel method for an efficient high-brilliance gamma-ray source. A giant collimated gamma-ray pulse is generated from the interaction of a dense ultra-relativistic electron beam with a thin solid conductor. Energetic gamma-rays are copiously produced as the electron beam splits into filaments while propagating across the conductor. The resulting gamma-ray energy and flux enable novel experiments in nuclear and fundamental physics.

The typical wavelength of light interacting with an object of the microcosm scales with the size of this object. For atoms, this ranges from visible light to...

Im Focus: Basel researchers succeed in cultivating cartilage from stem cells

Stable joint cartilage can be produced from adult stem cells originating from bone marrow. This is made possible by inducing specific molecular processes occurring during embryonic cartilage formation, as researchers from the University and University Hospital of Basel report in the scientific journal PNAS.

Certain mesenchymal stem/stromal cells from the bone marrow of adults are considered extremely promising for skeletal tissue regeneration. These adult stem...

Im Focus: Like a wedge in a hinge

Researchers lay groundwork to tailor drugs for new targets in cancer therapy

In the fight against cancer, scientists are developing new drugs to hit tumor cells at so far unused weak points. Such a “sore spot” is the protein complex...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

IWOLIA: A conference bringing together German Industrie 4.0 and French Industrie du Futur

09.04.2018 | Event News

 
Latest News

Scientists re-create brain neurons to study obesity and personalize treatment

20.04.2018 | Health and Medicine

Spider silk key to new bone-fixing composite

20.04.2018 | Materials Sciences

Clear as mud: Desiccation cracks help reveal the shape of water on Mars

20.04.2018 | Earth Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>