Picture: Jökulsárlón glaciers Iceland. Credit: Jeremy Goldberg (Unsplash)
The Arctic is warming at a rate almost twice that of the global average, resulting in a fast decrease in Arctic sea ice. At the same time, there has been an increase in primary production (biomass production) in the Arctic Ocean over the past two decades due to the decrease in sea-ice cover, which led to increased light availability for phytoplankton and ice algae. This has strong implications for global biogeochemical cycles and how much the Arctic Ocean will mitigate the increase in global greenhouse gases by acting as a sink for atmospheric carbon dioxide.
However, predicting how much primary production will further increase in the Arctic Ocean in coming decades depends on the interplay between the increase in light for primary producers, as the sea ice extent and thickness decrease, and the availability of food in the form of nutrients, such as nitrate, phosphate, and silica. Future trends in Arctic primary production also depend on changes in storm frequency, wind, freshwater flows, ocean stratification, water mixing with lower latitudes and possible changes in the chemical composition of these waters.
In this study, the researchers analysed data collected over more than three decades in the Western Eurasian Basin of the Arctic Ocean (1980–2016). They concluded that the nutrient concentrations of the various waters found in this area have not changed significantly, except for the surface waters, where there is a decreasing trend in silica concentration. This trend is consistent with the reported increase in primary production. The study provides a baseline for the nutrient composition of the waters found in the Western Eurasian Basin to be able to better follow their changes in the future.
- Paper: Duarte, P., Meyer, A., & Moreau, S. (2021). Nutrients in water masses in the Atlantic sector of the Arctic Ocean: Temporal trends, mixing and links with primary production. Journal of Geophysical Research: Oceans, 126, e2021JC017413. https://doi.org/10.1029/2021JC017413