Publication Date:
2023-07-13
Description:
Facing the ongoing intensification of the hydrological cycle, stable isotopes of O and H in streams and precipitation are cardinal tools to identify and assess the factors controlling catchment resilience to climate change. However, progress is stymied by the uncertainty related to the spatial and temporal variability of these tracers, mostly due to the limited availability of long-term historical observations. Here, we propose two complementary innovative approaches for reconstructing pre-instrumental δ〈sup〉18〈/sup〉O series in precipitation and stream water.First, we conjecture that oxygen isotopes inside the mineral structures of freshwater bivalve shells hold promising potential to extend limited stream water isotope records. Certain species can live up to 200 years (e.g., Margaritifera Margaritifera), and nearly 1200 species inhabit a large variety of river systems and lakes around the globe. Proof-of-concept work has already shown that shell-extracted δ〈sup〉18〈/sup〉O values closely mirror the variance of the measured stream water δ〈sup〉18〈/sup〉O – both showing a strong damping of the precipitation signal. Building on this, shell δ〈sup〉18〈/sup〉O chronologies were generated from three recently collected individuals collected from the Our River (L) extending back to the 1960s, comprising over 3000 samples. Our second conjecture, which we focus on here, states that precipitation δ〈sup〉18〈/sup〉O series may be reconstructed from historical atmospheric circulation data. Based on a 6 year-worth sub-daily resolution isotope dataset collected at the meteorological station in Belvaux (L) from 2017 to 2022, we built a multiple linear regression model explaining almost 50 percent of the sub-daily variance, and closely matching the monthly δ〈sup〉18〈/sup〉O signal.
Language:
English
Type:
info:eu-repo/semantics/conferenceObject
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