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Rock snot and lake mud: exploring the history of recent blooms of Didymosphenia geminata using information contained in lake sediments.

Lavery, J. Michelle; Kurek, Joshua; Rühland, Kathleen M.; Gillis, Carole-Anne; Pisaric, Michael F. J.; Smol, John P. (2014). Rock snot and lake mud: exploring the history of recent blooms of Didymosphenia geminata using information contained in lake sediments. Canadian Young Scientist Journal , vol. 2014 , nº 3. p. 32-41. DOI: 10.13034/cysj-2014-019.

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Résumé

Ecosystem managers have often considered the nuisance diatom species, Didymosphenia geminata (didymo) as being introduced to the natural environment through human activities; however, observations from early 20th-century surveys challenge this characterization. We use diatoms preserved in lake sediment cores to investigate the history of didymo blooms from Gaspésie, Quebec. Relative abundances of diatoms were examined from the dated sediments of Lac Humqui and Lac au Saumon (a lake with an inflowing river currently supporting blooms). Didymo was observed throughout the Lac au Saumon core, demonstrating that it has been present in the region well before the first reports of blooms in 2006. Lac Humqui diatom assemblages experienced a shift in composition with declines in benthic taxa (attached to substrates) and increases in planktonic (free floating) diatoms that began ∼1970. Strong relationships between this diatom shift, and increases in regional air temperatures and earlier river ice-out dates were consistent with the expected effects of climate warming on aquatic systems. Our paleolimnological evidence shows that climate warming, rather than human introduction, likely plays an important role in triggering didymo blooms.

Type de document: Article
Mots-clés libres: paleolimnology; climate Change; freshwater; diatoms; rivers
Centre: Centre Eau Terre Environnement
Date de dépôt: 17 avr. 2018 19:40
Dernière modification: 17 avr. 2018 19:40
URI: http://espace.inrs.ca/id/eprint/4262

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