Isotopic analyses ( 18 O, 13 C, 14 C) of two meromictic lakes in the Canadian Arctic Archipelago1

• Published in: Limnology and Oceanography
• Main Authors: Pagé, P., Ouellet, M., Hillaire‐Marcel, C., Dickman, M.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 1984
• Subjects: Aquatic Science; Oceanography; Arctic; Canadian Arctic Archipelago; Arctic Archipelago; permafrost
• Online Access: http://dx.doi.org/10.4319/lo.1984.29.3.0564; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.4319%2Flo.1984.29.3.0564; https://aslopubs.onlinelibrary.wiley.com/doi/pdf/10.4319/lo.1984.29.3.0564

Meromictic Lakes Garrow and Sophia in the Canadian Arctic Archipelago were sampled to establish the origin and age of their waters by isotopic studies. The δ smow 18 O values reflect the permanent stratification of the waters in both lakes. The mixolimnia contain waters with an isotopic signal between ‒13.16 and ‒21.98‰, coherent with the values for precipitation in these high latitudes. The short residence time of the water in this layer makes it possible to record episodic variations of the freshwater inputs to the lakes. In the chemoclines, the δ 18 O values increase to ‒10‰ concomitantly with a rise in chloride content to 42 g·liter ‒1 . This corresponds to a conservative mixing of surficial and deep waters. In the monimolimnia, hypersaline waters (up to 2.5 times the salinity of seawater) show negative δ 18 O values (ca. ‒8‰). These waters result from brine production during permafrost growth in the watershed, according to a Rayleigh process. The brines drained toward the deepest part of each lake, after postglacial uplift, and became isolated. 14 C dating of total inorganic carbon in the Lake Garrow monimolimnion gave an age of 2,580 ± 260 years b.p. In Lake Sophia, the deep waters exhibit recent 14 C activity (121.4% modern carbon) that suggests recent infiltration of seawater into the lake basin.