Work

Temporal and spatial trends in eutrophication status in the Oslofjord, Norway

Year: 2025

Type: article

Abstract: The eutrophication status of the Oslofjord, Norway, was assessed using 1) existing monitoring data, 2) established assessment criteria, and 3) an updated version of the HELCOM Eutrophication Assessment Tool (HEAT), which is widely employed in Europe. The analysis, covering the period from 1960 to 2023, revealed persistent ‘eutrophication problem areas’ in specific regions of the Oslofjord, particularly in inner areas and those situated downstream of large catchments and urban centres. This assessment demonstrated that the Oslofjord has been classified as a ‘eutrophication problem area’ for more than five decades. These findings, including basin- and criteria-specific distance-to-target estimates, provide a foundation for establishing evidence-based nutrient management strategies in the Oslofjord and its upstream catchments. In the absence of reduced nutrient inputs, a significant portion of the Oslofjord will continue to be classified as a ‘problem area’. • Integrated assessment of long-term eutrophication status of heavily impacted fjord • Applies assessment criteria using HELCOM Eutrophication Assessment Tool (HEAT) • Identifies fjord as ‘eutrophication problem area’ for more than five decades • Baseline for managing nutrient enrichment in Oslofjord and upstream catchments

Source: The Science of The Total Environment

DOI: 10.1016/j.scitotenv.2025.179462

Authors: Paula Ramon, Jesper H. Andersen, Ciarán J. Murray, Helene Frigstad

Institution: Norwegian Institute for Water Research

Language: English

Topic: Marine and coastal ecosystems

Subfield: Oceanography

Field: Earth and Planetary Sciences

Domain: Physical Sciences

SDGs: Clean water and sanitation, Life below water

Open Access status: hybrid

Estimated APC paid: $4,250