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KEY MESSAGE

This core indicator evaluates average oxygen debt below the halocline that separates deep water from the surface water. Oxygen debt is applied in the Bornholm Basin, Gdansk basin, Western Gotland Basin, Eastern Gotland Basin, Northern Baltic Proper and Gulf of Finland. Oxygen debt values below the threshold value have not been achieved in any of these sub-basins.

Oxygen debt below the halocline has increased in all basins since the early 1900's.

 

Oxygen debt 2018 2.jpg

Key message figure 1. Status assessment results based on evaluation of the indicator 'Oxygen debt'. The assessment is carried out using open sea areas of Scale 4 HELCOM assessment units (defined in the HELCOM Monitoring and Assessment Strategy Annex 4). See Results section below for details. Click here to access interactive maps at the HELCOM Map and Data Service: Oxygen debt.

 

The confidence of the presented oxygen debt status estimate is high in all the sub-basins where the indicator was applied.

 

RELEVANCE OF THE CORE INDICATOR

Organic matter deposition to bottom waters increases along with increasing eutrophication. This leads to increasing oxygen consumption and a subsequent decrease in bottom oxygen concentration.

 

POLICY RELEVANCE OF THE CORE INDICATOR

  BSAP Segment and ObjectivesMSFD Descriptors and Criteria
Primary linkA Baltic Sea unaffected by eutrophication

D5 Human-induced eutrophication

- D5C5 The concentration of dissolved oxygen is not reduced, due to nutrient enrichment, to levels that indicate adverse effects on benthic habitats (including on associated biota and mobile species) or other eutrophication effects.

Secondary link 
Other relevant legislation: EU Water Framework Directive ‚Äč

 

CITE THIS INDICATOR

HELCOM (2018). Oxygen debt. HELCOM core indicator report. Online. [Date Viewed], [Web link].

ISSN 2343-2543

 

DOWNLOAD FULL INDICATOR REPORT

Oxygen debt HELCOM core indicator 2018 (pdf)