Denmark coastal waters face alarming oxygen depletion

Oxygen depletion levels along Danish coasts have reached alarming heights for the third consecutive year. New data from the Agency for Green Area Conversion and Water Environment and Danmarks Naturfredningsforening indicate that more than one-third of Denmark’s 108 coastal waters—specifically 38 areas—have already been affected by oxygen depletion in 2026.

This figure represents an increase compared to the previous two years. Experts and environmental organizations attribute the phenomenon primarily to rising temperatures and nitrogen runoff from agricultural activities. In some regions, such as Aarhus Bugt, the impact is particularly severe, with observations of record-early algae growth.

Local observations highlight the ecological consequences, including significant declines in fish populations. In areas like Helnæs Bugt, local fishers report a drastic reduction in trout numbers. Scientists from Aarhus University note a trend toward rapid establishment of severe oxygen depletion, particularly in the waters surrounding Funen.