Nutrient inputs from rivers and coastal erosion are of crucial importance for marine ecosystems in the Arctic Ocean
In the Arctic Ocean, primary production by phytoplankton sustains a unique ecosystem. The availability of nutrients represents a limiting factor of this phytoplankton growth. So far, it was largely believed that these nutrients stem largely from other parts of the global ocean, such as the Atlantic or Pacific Ocean. Not well known is the role of the nutrients from land that enter the Arctic Ocean via rivers and through the erosion of coastal soils. In a study published today in Nature Communications, an international team of scientists from the IPSL in Paris, the Université Libre de Bruxelles, the ETH Zürich, and the University of Bern provides an estimate of terrestrial nutrient inputs, with riverine fluxes being based on observations at the six largest Arctic rivers and erosion fluxes being based on satellite images of the Arctic coastline and measurements of the nutrient content in these eroding soils. With a state-of-the-art high-resolution ocean-biogeochemical model, it was estimated that terrigenous nutrients sustain 28-51 % of the total Arctic Ocean productivity. This study suggests a much more prominent imprint of terrestrial inputs on the Arctic Ocean ecosystem.
Reference :
Jens Terhaar, Ronny Lauerwald, Pierre Regnier, Nicolas Gruber & Laurent Bopp, Around one third of current Arctic Ocean primary production sustained by rivers and coastal erosion, Nature Communications, 8th January 2020, 10.1038/s41467-020-20470-z.
