Constellation, le dépôt institutionnel de l'Université du Québec à Chicoutimi

Hidden stores of organic matter in northern lake ice : Selective retention of terrestrial particles, phytoplankton and labile carbon

Imbeau Elise, Vincent Warwick F., Wauthy Maxime, Cusson Mathieu et Rautio Milla. (2021). Hidden stores of organic matter in northern lake ice : Selective retention of terrestrial particles, phytoplankton and labile carbon. Journal of Geophysical Research: Biogeosciences, 126, (8), e2020JG006233.

[img]
Prévisualisation
PDF - Version publiée
1MB

URL officielle: http://dx.doi.org/doi:10.1029/2020JG006233

Résumé

Around 50% of the world's lakes freeze seasonally, but the duration of ice-cover is shortening each year and this is likely to have broad limnological consequences. We sampled freshwater ice and the underlying water in 19 boreal and polar lakes to evaluate whether lake ice contains an inoculum of algae, nutrients, and carbon that may contribute to lake ecosystem productivity. Boreal and Arctic lakes differed in ice duration (6 vs. >10 months), thickness (70 vs. 190 cm), and quality (predominantly snow ice vs. black ice), but in all lakes, there were consistent differences in biological and biogeochemical composition between ice and water. Particulate fractions were often more retained while most dissolved compounds were excluded from the ice; for example, the ice had more terrestrial particulate carbon, measured as fatty acid biomarkers (averages of 1.1 vs. 0.3 µg L−1) but lower dissolved organic carbon (2.2 vs. 5.7 mg C L−1) and inorganic phosphorus concentrations (4.0 vs. 7.5 µg C L−1) than the underlying water. The boreal ice further had three times higher chlorophyll-a, than the water (0.9 vs. 0.3 µg L−1). Of the dissolved fractions, the contribution of protein-like compounds was higher in the ice, and this in all lakes. These labile compounds would become available to planktonic microbes when the ice melts. Our results show that freshwater ice has an underestimated role in storage and transformation in the biogeochemical carbon cycle of ice-covered lake ecosystems.

Type de document:Article publié dans une revue avec comité d'évaluation
ISSN:2169-8953
Volume:126
Numéro:8
Pages:e2020JG006233
Version évaluée par les pairs:Oui
Date:2021
Identifiant unique:10.1029/2020JG006233
Sujets:Sciences naturelles et génie > Sciences appliquées > Eau et environnement
Sciences naturelles et génie > Sciences naturelles > Biologie et autres sciences connexes
Sciences naturelles et génie > Sciences naturelles > Chimie
Département, module, service et unité de recherche:Départements et modules > Département des sciences fondamentales
Mots-clés:ice lake, lacustrine environment, lake ecosystem, phytoplankton, ice cover, carbon cycle, dissolved organic carbon
Déposé le:27 avr. 2022 23:38
Dernière modification:27 avr. 2022 23:38
Afficher les statistiques de telechargements

Éditer le document (administrateurs uniquement)

Creative Commons LicenseSauf indication contraire, les documents archivés dans Constellation sont rendus disponibles selon les termes de la licence Creative Commons "Paternité, pas d'utilisation commerciale, pas de modification" 2.5 Canada.

Bibliothèque Paul-Émile-Boulet, UQAC
555, boulevard de l'Université
Chicoutimi (Québec)  CANADA G7H 2B1
418 545-5011, poste 5630