Deepened snow increases late thaw biogeochemical pulses in mesic low arctic tundra

Kate M. Buckeridge*, Paul Grogan

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Pulses of plant-available nutrients to the soil solution are expected to occur during the dynamic winter-spring transition in arctic tundra. Our aims were to quantify the magnitude of these potential nutrient pulses, to understand the sensitivity of these pulses to winter conditions, and to characterize and integrate the environmental and biogeochemical dynamics of this period. To test the hypotheses that snow depth, temperature and soil water-and not snow nutrient content-are important controls on winter and spring biogeochemistry, we sampled soil from under ambient and deepened snow every 3 days from late winter to spring, in addition to the snowpack at the start of thaw. Soil and microbial biogeochemical dynamics were divided into distinct phases that correlated with steps in soil temperature and soil water. Soil solution and microbial pools of C, N and P fluctuated with strong peaks and declines throughout the thaw, especially under deepened snow. Snowpack nutrient accumulation was negligible relative to these biogeochemical peaks. All nutrient and microbial peaks declined simultaneously at the end of snowmelt and so this decline was delayed by 15 days under deepened snow. The timing of these nutrient pulses is critical for plant species nutrient availability and landscape nutrient budgets. This detailed and statistically-based characterisation of the winter-spring transition in terms of environmental and biogeochemical variables should provide a useful foundation for future biogeochemical process-based studies of thaw, and indicate that spring thaw and possibly growing season biogeochemical dynamics are sensitive to present and future variability in winter snow depth.

Original languageEnglish
Pages (from-to)105-121
Number of pages17
JournalBiogeochemistry
Volume101
Issue number1-3
DOIs
Publication statusPublished - Dec 2010
Event6th International Symposium on Ecosystem Behavior - Helsinki, Finland
Duration: 29 Jun 20093 Jul 2009

Keywords

  • Nitrogen
  • Phosphorus
  • Carbon
  • Low arctic birch hummock tundra
  • Spring thaw
  • Snow depth
  • DISSOLVED ORGANIC-MATTER
  • CARBON-DIOXIDE EXCHANGE
  • BIRCH HUMMOCK TUNDRA
  • MICROBIAL BIOMASS
  • ALPINE ECOSYSTEM
  • NITROGEN UPTAKE
  • DISCONTINUOUS PERMAFROST
  • BIOLOGICAL PROCESSES
  • BOREAL FOREST
  • SOIL

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