Potential effects of reduced riverine inorganic particle loading on water quality in the Oslofjord region

Summary

A model investigation was carried out of the potential impacts of reduced riverine inorganic particle loading in the Oslofjord region. Some significant improvements in water clarity, particularly in the Glomma estuary, were projected by the model for a 100% reduction in inorganic particle loading. This was partly offset by an intensification of phytoplankton blooms, due to more light availability, although this did not strongly impact bottom water dissolved oxygen levels. More focused modelling and observational work is recommended before any large-scale implementation of particle reduction measures, in view of the risks of exacerbating eutrophication and potential harmful algal blooms, and a potential need for concurrent reductions in nutrient loading to minimize these risks.