Abstract
Abstract. The stable isotope composition of lacustrine sediments is routinely used to infer Late Holocene changes in precipitation over Scandinavia and, ultimately, atmospheric circulation dynamics in the North Atlantic realm. However, such archives only provide a low temporal resolution (ca. 15 years), precluding the ability to identify changes on inter-annual and quasi-decadal timescales. Here, we present a new, high-resolution reconstruction using shells of freshwater pearl mussels, Margaritifera margaritifera, from three streams in northern Sweden. We present seasonally to annually resolved, calendar-aligned stable oxygen and carbon isotope data from 10 specimens, covering the time interval from 1819 to 1998. The bivalves studied formed their shells near equilibrium with the oxygen isotope signature of ambient water and, thus, reflect hydrological processes in the catchment as well as changes, albeit damped, in the isotope signature of local atmospheric precipitation. The shell oxygen isotopes were significantly correlated with the North Atlantic Oscillation index (up to 56 % explained variability), suggesting that the moisture that winter precipitation formed from originated predominantly in the North Atlantic during NAO+ years but in the Arctic during NAO− years. The isotope signature of winter precipitation was attenuated in the stream water, and this damping effect was eventually recorded by the shells. Shell stable carbon isotope values did not show consistent ontogenetic trends, but rather oscillated around an average that ranged from ca. −12.00 to −13.00 ‰ among the streams studied. Results of this study contribute to an improved understanding of climate dynamics in Scandinavia and the North Atlantic sector and can help to constrain eco-hydrological changes in riverine ecosystems. Moreover, long isotope records of precipitation and streamflow are pivotal to improve our understanding and modeling of hydrological, ecological, biogeochemical and atmospheric processes. Our new approach offers a much higher temporal resolution and superior dating control than data from existing archives.
Highlights
Multi-decadal records of δ18O signals in precipitation and stream water are important for documenting climate change impacts on river systems (Rank et al, 2017), improving the mechanistic understanding of water flow and quality controlling processes (Darling and Bowes, 2016), and testing Earth hydrological and land surface models (Reckerth et al, 2017; Risi et al, 2016; see Tetzlaff et al, 2014)
Schöne et al.: Freshwater pearl mussels as long-term, high-resolution stream water isotope recorders ies, the temporal changes in the oxygen isotope signatures of meteoric water are encoded in biogenic tissues and abiogenic minerals formed in rivers and lakes (e.g., Teranes and McKenzie, 2001; Leng and Marshall, 2004)
Many studies have determined the oxygen isotope composition of diatoms, ostracods, authigenic carbonate and aquatic cellulose preserved in lacustrine sediments to reconstruct Late Holocene changes in precipitation over Scandinavia and, atmospheric circulation dynamics in the North Atlantic realm (e.g., Hammarlund et al, 2002; Andersson et al, 2010; Rosqvist et al, 2004, 2013)
Summary
Multi-decadal records of δ18O signals in precipitation and stream water are important for documenting climate change impacts on river systems (Rank et al, 2017), improving the mechanistic understanding of water flow and quality controlling processes (Darling and Bowes, 2016), and testing Earth hydrological and land surface models (Reckerth et al, 2017; Risi et al, 2016; see Tetzlaff et al, 2014). Many studies have determined the oxygen isotope composition of diatoms, ostracods, authigenic carbonate and aquatic cellulose preserved in lacustrine sediments to reconstruct Late Holocene changes in precipitation over Scandinavia and, atmospheric circulation dynamics in the North Atlantic realm (e.g., Hammarlund et al, 2002; Andersson et al, 2010; Rosqvist et al, 2004, 2013) With their short residence times of a few months (Rosqvist et al, 2013), the hydrologically connected, through-flow lakes of northern Scandinavia are an ideal region for this type of study. While sediment records are still of vital importance for century-scale and millennial-scale variations, new approaches are needed for finer-scale resolution on the 1–100-year timescale
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
