Efficient protection of the Baltic Sea needs a revision of phosphorus metric

Abstract

Eutrophication of the Baltic Sea is driven by phosphorus and nitrogen. While the anthropogenic point source loads of both nutrients have decreased markedly, further reductions are needed. This is true particularly for phosphorus, as highlighted by its stringent abatement targets in HELCOM’s Baltic Sea Action Plan. To meet the targets, more results need to be achieved in non-point source abatement, specifically from agricultural sources. The growing pressure for phosphorus abatement from agriculture may lead to environmentally and economically inefficient outcomes unless we account for the variability in how different forms of phosphorus respond to abatement measures, and how these forms contribute to eutrophication. The precautionary and efficiency improving way to advance policies is to either replace or supplement the Total Phosphorus metric with a metric more accurate in reflecting the biologically available phosphorus. This policy fix becomes more important as the relative share of agricultural emissions of total pollution increases.

Managing multi-functional peri-urban landscapes: Impacts of horse-keeping on water quality

“…Horse farms in peri-urban areas can thus be considered as nutrient hot-spots, as most of the fodder is imported to the catchment, the manure is seldom recycled within the catchment, and intense trampling contributes to increased nutrient losses from the soil. To prevent further accumulation and losses of nutrients, the recycling of manure and human sewage need to be more efficient (McCrackin et al 2018a ; Svanbäck et al 2019 ; Pihlainen et al 2020 ), and to enhance the efficiency in environmental and economic outcomes, abatement work should focus on the dissolved and thus biologically available P (Iho et al 2023 ).…”