Modern Eastern Canadian Arctic Lake Water Isotopes Exhibit Latitudinal Patterns in Inflow Seasonality and Minimal Evaporative Enrichment

作者：Devon Gorbey, Elizabeth K. Thomas, Peter E. Sauer, Martha K. Raynolds, Gifford H. Miller, Megan C. Corcoran, Owen Cowling, Sarah E. Crump, K. Lovell, Jonathan H. Raberg · 发表于：Paleoceanography and Paleoclimatology · 年份：2022 · DOI：10.1029/2021pa004384 · 被引用次数：12 · 研究领域：Climate change and permafrost、Cryospheric studies and observations、Geology and Paleoclimatology Research

Abstract Lacustrine δ 2 H and δ 18 O isotope proxies are powerful tools for reconstructing past climate and precipitation changes in the Arctic. However, robust paleoclimate record interpretations depend on site‐specific lake water isotope systematics, which are poorly described in the eastern Canadian Arctic due to insufficient modern lake water isotope data. We use modern lake water isotopes (δ 18 O and δ 2 H) collected between 1994–1997 and 2017–2021 from a transect of sites spanning a Québec‐to‐Ellesmere Island gradient to evaluate the effects of inflow seasonality and evaporative enrichment on the δ 2 H and δ 18 O composition of lake water. Four lakes near Iqaluit, Nunavut sampled biweekly through three ice‐free seasons reflect mean annual precipitation isotopes with slight evaporative enrichment. In a 23° latitudinal transect of 181 lakes, through‐flowing lake water δ 2 H and δ 18 O fall along local meteoric water lines. Despite variability within each region, we observe a latitudinal pattern: southern lakes reflect mean annual precipitation isotopes, whereas northern lakes reflect summer‐biased precipitation isotopes. This pattern suggests that northern lakes are more fully flushed with summer precipitation, and we hypothesize that this occurs because the ratio of runoff to precipitation increases with latitude as vegetation cover decreases. Therefore, proxy records from through‐flowing lakes in this region should reflect precipitation isotopes with minimal influence o...