Regimes of primary production and their drivers in Alpine streams

Marta Boix Canadell, Lluís Gómez-Gener, Amber J. Ulseth, Mélanie Clémençon, Stuart N. Lane, Tom J. Battin

Research output: Contribution to journalArticlepeer-review

14 Scopus citations

Abstract

Primary production is a fundamental ecosystem process that influences nutrient and carbon cycling, and trophic structure in streams. The magnitude and timing of gross primary production (GPP) are typically controlled by hydrology, light, nutrient availability and grazers. Estimates of GPP and its drivers in high-mountain streams remain elusive at present. We estimated GPP in streams typical for high-mountain catchments, namely a glacier-fed, groundwater-fed (krenal) and a snowmelt-fed (nival) stream. Using high-resolution sensor data over 2 years in combination with numerical simulations of stream hydraulics, we studied the periods of GPP characteristic for these streams, as well as their major drivers. Favourable windows for GPP were constrained to periods at the onset of the snowmelt and its recession, when photosynthetic active radiation at the streambed and streambed stability facilitated GPP. During these windows of opportunity, GPP was higher in the nival stream (3.7 ± 3.4 g O2 m−2 day−1), followed by the glacier-fed (1.5 ± 1.6 g O2 m−2 day−1) and the krenal streams (0.6 ± 0.6 g O2 m−2 day−1). GPP was largely controlled by photosynthetic active radiation at the stream bottom, however, we were not able to establish an unequivocal relationship between flow-induced bed movement and GPP. Our results highlight the capacity of primary producers to exploit the discrete and relatively predictable windows of opportunities in high-mountain streams. We propose that climate-driven change in snow and glacier melt reduction may ameliorate stream environmental conditions, thereby enhancing the potential autochthonous organic matter supply within the catchment.

Original languageEnglish (US)
Pages (from-to)1449-1463
Number of pages15
JournalFreshwater Biology
Volume66
Issue number8
DOIs
StatePublished - Aug 2021
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2021 John Wiley & Sons Ltd.

Keywords

  • ecosystem metabolism
  • global warming
  • high-mountain streams
  • hydrological regimes
  • streambed disturbance

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