Deep roots of Carex aquatilis have greater ammonium uptake capacity than shallow roots in peatlands following permafrost thaw

Lucas J. Albano, Merritt R. Turetsky, Michelle C. Mack, Evan S. Kane

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

Aims: Climate warming in northern ecosystems is triggering widespread permafrost thaw, during which deep soil nutrients, such as nitrogen, could become available for biological uptake. Permafrost thaw shift frozen organic matter to a saturated state, which could impede nutrient uptake. We assessed whether soil nitrogen can be accessed by the deep roots of vascular plants in thermokarst bogs, potentially allowing for increases in primary productivity. Methods: We conducted an ammonium uptake experiment on Carex aquatilis Wahlenb. roots excavated from thermokarst bogs in interior Alaska. Ammonium uptake capacity was compared between deep and shallow roots. We also quantified differences in root ammonium uptake capacity and plant size characteristics (plant aboveground and belowground biomass, maximum shoot height, and maximum root length) between the actively-thawing margin and the centre of each thermokarst bog as a proxy for time-following-thaw. Results: Deep roots had greater ammonium uptake capacity than shallow roots, while rooting depth, but not belowground biomass, was positively correlated with aboveground biomass. Although there were no differences in aboveground biomass between the margin and centre, our findings suggest that plants can benefit from investing in the acquisition of resources near the vertical thaw front. Conclusions: Our results suggest that deep roots of C. aquatilis can contribute to plant nitrogen uptake and are therefore able to tolerate anoxic conditions in saturated thermokarst bogs. This work furthers our understanding of how subarctic and wetland plants respond to warming and how enhanced plant biomass production might help offset ecosystem carbon release with future permafrost thaw.

Original languageEnglish (US)
Pages (from-to)261-272
Number of pages12
JournalPlant and Soil
Volume465
Issue number1-2
DOIs
StatePublished - Aug 2021

Keywords

  • Ammonium uptake
  • Boreal
  • Carex aquatilis
  • Peatland
  • Permafrost carbon
  • Thermokarst

ASJC Scopus subject areas

  • Soil Science
  • Plant Science

Fingerprint

Dive into the research topics of 'Deep roots of Carex aquatilis have greater ammonium uptake capacity than shallow roots in peatlands following permafrost thaw'. Together they form a unique fingerprint.

Cite this