A global compilation of diatom silica oxygen isotope records from lake sediment – trends and implications for climate reconstruction

oleh: P. Meister, A. Alexandre, H. Bailey, P. Barker, B. K. Biskaborn, E. Broadman, R. Cartier, R. Cartier, B. Chapligin, M. Couapel, J. R. Dean, B. Diekmann, B. Diekmann, P. Harding, P. Harding, A. C. G. Henderson, A. Hernandez, U. Herzschuh, U. Herzschuh, U. Herzschuh, S. S. Kostrova, J. Lacey, M. J. Leng, M. J. Leng, A. Lücke, A. W. Mackay, E. K. Magyari, B. Narancic, B. Narancic, C. Porchier, G. Rosqvist, A. Shemesh, C. Sonzogni, G. E. A. Swann, F. Sylvestre, H. Meyer

Format: Article
Diterbitkan: Copernicus Publications 2024-02-01

Deskripsi

<p>Oxygen isotopes in biogenic silica (<span class="inline-formula"><i>δ</i><sup>18</sup>O<sub>BSi</sub></span>) from lake sediments allow for quantitative reconstruction of past hydroclimate and proxy-model comparison in terrestrial environments. The signals of individual records have been attributed to different factors, such as air temperature (<span class="inline-formula"><i>T</i><sub>air</sub></span>), atmospheric circulation patterns, hydrological changes, and lake evaporation. While every lake has its own local set of drivers of <span class="inline-formula"><i>δ</i><sup>18</sup>O</span> variability, here we explore the extent to which regional or even global signals emerge from a series of paleoenvironmental records. This study provides a comprehensive compilation and combined statistical evaluation of the existing lake sediment <span class="inline-formula"><i>δ</i><sup>18</sup>O<sub>BSi</sub></span> records, largely missing in other summary publications (i.e. PAGES network). For this purpose, we have identified and compiled 71 down-core records published to date and complemented these datasets with additional lake basin parameters (e.g. lake water residence time and catchment size) to best characterize the signal properties. Records feature widely different temporal coverage and resolution, ranging from decadal-scale records covering the past 150 years to records with multi-millennial-scale resolution spanning glacial–interglacial cycles. The best coverage in number of records (<span class="inline-formula"><i>N</i></span> <span class="inline-formula">=</span> 37) and data points (<span class="inline-formula"><i>N</i></span> <span class="inline-formula">=</span> 2112) is available for Northern Hemispheric (NH) extratropical regions throughout the Holocene (roughly corresponding to Marine Isotope Stage 1; MIS 1). To address the different variabilities and temporal offsets, records were brought to a common temporal resolution by binning and subsequently filtered for hydrologically open lakes with lake water residence times <span class="inline-formula">&lt;</span> 100 years. For mid- to high-latitude (<span class="inline-formula">&gt;</span> 45° N) lakes, we find common <span class="inline-formula"><i>δ</i><sup>18</sup>O<sub>BSi</sub></span> patterns among the lake records during both the Holocene and Common Era (CE). These include maxima and minima corresponding to known climate episodes, such as the Holocene Thermal Maximum (HTM), Neoglacial Cooling, Medieval Climate Anomaly (MCA) and the Little Ice Age (LIA). These patterns are in line with long-term air temperature changes supported by previously published climate reconstructions from other archives, as well as Holocene summer insolation changes. In conclusion, oxygen isotope records from NH extratropical lake sediments feature a common climate signal at centennial (for CE) and millennial (for Holocene) timescales despite stemming from different lakes in different geographic locations and hence constitute a valuable proxy for past climate reconstructions.</p>