Nutrient uptake controls and limitation dynamics in north-east Greenland streams

Research output: Contribution to journalArticlepeer-review

Authors

Colleges, School and Institutes

External organisations

  • Department of Atmospheric Environment and Aquatic Ecosystem
  • Shinshu University
  • Aarhus Universitet
  • Institute of Arctic Biology
  • University of Fairbanks; Institute of Arctic Biology; Fairbanks Alaska 99611 USA

Abstract

Permafrost thaw induced by climate change will cause increased release of nutrients and organic matter from the active layer to Arctic streams and, with increased water temperature, will potentially enhance algal biomass and nutrient uptake. Although essential for accurately predicting the response of Arctic streams to environmental change, knowledge of nutrient release on current Arctic in-stream processing is limited. Addressing this research gap, we quantified nutrient uptake of short-term releases of NO3, PO43- and NH4+ during peak snowmelt season in five streams of contrasting physiochemical characteristics (from unstable, highly turbid to highly stable, clear-water systems) in north-east Greenland to elucidate the major controls driving nutrient dynamics. Releases were plus or minus acetate to evaluate uptake dynamics with and without a dissolved organic carbon source. To substantiate limiting nutrients to algal biomass, nutrient-diffusing substrates were installed in the five streams for 16 days with NH4+, PO43- or NH4+ + PO43- on organic and inorganic substrates. Observed low uptake rates were due to a combination of low nutrient and DOC concentrations, combined with low water temperature and primary producer biomass, and substantial variation occurred between streams. N was found to be the primary limiting nutrient for biofilm, whilst streams displayed widespread PO43- limitation. This research has important implications for future changes in nutrient processing and export in Arctic streams, which are predicted to include increased nutrient uptake rates due to increased nutrient availability, warmer water temperatures and increased concentration of labile carbon. These changes could have ecosystem and landscape-wide impacts.

Details

Original languageEnglish
Article number1440107
JournalPolar Research
Volume37
Issue number1
Publication statusPublished - 19 Mar 2018

Keywords

  • Arctic, biofilm, biogeochemistry, climate change, freshwater, river