Rapid decrease of the Labrador Sea’s influence on black spruce ecosystems with distance inland

• Published in: Communications Earth & Environment
• Main Authors: Julien Larose, Étienne Boucher, Anne de Vernal, Ignacio Hermoso de Mendoza, Fabio Gennaretti, Aliénor Lavergne, Laia Andreu-Hayles, Robert D. Field
• Format: Article in Journal/Newspaper
• Language: English
• Published: Nature Portfolio 2024
• Subjects: Geology; QE1-996.5; Environmental sciences; GE1-350; Canada; Labrador Sea; Northwest Atlantic
• Online Access: https://doi.org/10.1038/s43247-024-01271-4; https://doaj.org/article/ac74c99cb2314da6bff1ee9f8ab04520

Abstract In eastern Canada, Black spruce (Picea mariana Mill. B.S.P.) grows in a wide variety of climates, from maritime-oceanic conditions near the Labrador Sea, to more continental climates, inland. Along this gradient, timing and provenance of heat and moisture that support growth are uncertain, weakening our capacity to predict the response of boreal ecosystems to climate variability. Here, we measured the stable oxygen isotopic composition of black spruce tree-ring cellulose at three sites in eastern Canada and provide evidence of a rapid decrease of Labrador Sea’s influence on adjacent ecosystems. Our results report a landwards decrease in the oxygen isotope composition of both tree-ring cellulose (δ 18O T R C ) and precipitation water (δ 18O p ). We also reveal a rapid landwards decoupling between δ 18O T R C variability (1950-2013), maximum temperature and Sea Surface Temperature variations over the Northwest Atlantic. Thus, despite their apparent ecological homogeneity, eastern Canada’s black spruce ecosystems rely on heterogeneous sources of heat and moisture.