Plants forage for deep nitrogen in the High Arctic
In the High Arctic, plant growth is restricted by the short growing season and limited nutrients. However, as the Arctic continues to warm due to climate change, nutrient availability may increase in both shallow soil layers due to increased decomposition, and in the deep soil due to permafrost thaw. Whether arctic plants can take advantage of these new nutrients depends on when and where in the soil profile these nutrients become available.
A recent study published in Global Change Biology investigates plant nitrogen uptake in a high arctic permafrost ecosystem. The study shows that not only do high arctic plants remain active in autumn, they also take up nitrogen released from thawing permafrost. Plant roots provide an important vertical transport system, e.g. by transporting permafrost-nitrogen from the deep soil to surface soil layers. Yet, plant species differ in terms of where in the soil profile they can take up nitrogen – some plants have shallow root networks and primarily take up nitrogen in the top soil, whereas other plants are able to tap into deep-soil nitrogen pools. In the long term, plant species that can capture deep nitrogen may have a competitive advantage in terms of avoiding competition with microorganisms and accessing permafrost-released nutrients. Such species differences will play an important role in determining how arctic plant communities might shift with future climate change.
Pedersen, E.P., Elberling, B., Michelsen, A. (2020). Foraging deeply: Depth-specific plant nitrogen uptake in response to climate-induced N-release and permafrost thaw in the High Arctic. Global Change Biology, https://doi.org/10.1111/gcb.15306.
Emily Pickering Pedersen
PhD student, Department of Biology, University of Copenhagen
Professor, Department of Biology, University of Copenhagen