Laboratory growth capacity of an invasive cyanobacterium (Microcystis aeruginosa) on organic substrates from surface waters of permafrost peatlands

• Published in: Environmental Science: Processes & Impacts
• Main Authors: Payandi-Rolland, Dahédrey, Shirokova, Liudmila, Larieux, Julien, Bénézeth, Pascale, Pokrovsky, Oleg
• Other Authors: Géosciences Environnement Toulouse (GET), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France-Centre National de la Recherche Scientifique (CNRS), Tomsk State University Tomsk
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2023
• Subjects: thermokarst lake; moss; lichen; growth; proliferation; laboratory experiment; [SDV.MP.BAC]Life Sciences [q-bio]/Microbiology and Parasitology/Bacteriology; [SDV.EE.BIO]Life Sciences [q-bio]/Ecology; environment/Bioclimatology; permafrost; Thermokarst
• Online Access: https://hal.science/hal-04189443; https://hal.science/hal-04189443/document; https://hal.science/hal-04189443/file/EM-ART-11-2022-000456_Revised-HAL.pdf; https://doi.org/10.1039/d2em00456a

International audience Within a global warming trend, invasive cyanobacteria, abundant in tropical and temperate regions, can migrate northward and colonize thermokarst lakes in permafrost-affected territories. Towards a better understanding of the cyanobacterial proliferation mechanism in those lakes, we performed laboratory growth of typical invasive cyanobacteria, Microcystis aeruginosa, onto various organic-rich solutions representative of permafrost peatlands. Aqueous leachates of lichen, moss and peat were the most favorable substrates for massive growth. The growth in the presence of all organic substrates produced a rise in solution pH by two units and a sizable (30-50%) decrease in the concentration of dissolved organic carbon. The observed increase of dissolved organic carbon aromaticity degree likely reflected preferential cyanobacterial uptake of aliphatic, optically transparent organic substances. Cyanobacterial growth over a bloom period can create a carbon sink (uptake of 2.5 and 8.3 g C-CO2 m-2 d-1) that can offset the net heterotrophic status of thermokarst lakes in the permafrost peatlands, thus switching the lake status from C source to C sink. Therefore, predictions of the future carbon exchanges with the atmosphere in surface waters of permafrost peatlands require explicit accounting for the possibility of invasive cyanobacterial growth.