Aquatic and Terrestrial Plant Contributions to Sedimentary Plant Waxes in a Modern Arctic Lake Setting

Abstract

The Arctic is the fastest-warming region on Earth, with mean annual temperatures expected to increase 10°C by the end of the century under the most extreme scenarios (IPCC, 2021). Arctic precipitation is also expected to increase as local evaporation from newly ice-free seas and poleward moisture transport increase (Bintanja & Andry, 2017) (Singh et al., 2017). This rapid climate change is exacerbated by positive feedbacks primarily linked to decreasing albedo (Holland & Bitz, 2003). Records of past Arctic climate change, including water cycle change, can provide crucial long-term perspectives to understand how this region will respond to future climate change.

Mid- and long-chain leaf wax δ2H values in modern plants and lake sediments from mid-latitude North America

“…The lower εapp values in aquatic plants compared to angiosperms and gymnosperms is consistent with previous findings (Chikaraishi and Naraoka, 2003;Duan et al, 2014;Aichner et al, 2017;Dion-Kirschner et al, 2020). Mosses are another possible contributor to the sedimentary n-C23 pool as they have been shown to primarily synthesize mid-chain n-alkanes (Sachse et al, 2006;Nichols et al, 2009;Bush and McInerney, 2013;Hollister et al, 2022). Although we did not sample mosses in this study, moss εC39/MAP values have been shown to be more positive than those of terrestrial plants (Sachse et al, 2006).…”

In the Weeds: Aquatic Plant Biomarker Sources to Arctic Lake Sediments

“…The contrasting results from Hollister et al (2022) and Dion-Kirschner et al (2020) highlight the variability of plant wax production, transport, and deposition in high latitude lakes. Continued efforts to fingerprint the sources n-alkyl compounds, and to build a mechanistic understanding of biomarker and isotope systematics, will support applications of the dual-biomarker isotope method for reconstructing past changes in Arctic humidity and precipitation seasonality.…”

“…The contrasting results from Hollister et al. (2022) and Dion‐Kirschner et al. (2020) highlight the variability of plant wax production, transport, and deposition in high latitude lakes.…”

“…By incorporating δ 2 H wax and δ 13 C wax into the analysis, they were able to distinguish the plant sources more clearly. Hollister et al (2022) combine their geochemical results with vegetation mapping in and around the lake to gain a mechanistic understanding of the sources, transport, and deposition of the plant waxes. The authors propose that a combination of factors explain the aquatic origin of mid-chain n-alkyl compounds at Qaupat Lake (Figure 1).…”

“…In addition to the ongoing lipid fingerprinting addressed by Hollister et al. (2022), the dual‐biomarker proxy system will profit from research on how leaf water and lake water δ 2 H signatures relate to climatic parameters in the Arctic (Anderson et al., 2013; Cluett et al., 2021; Cluett & Thomas, 2020; Tondu et al., 2013). Previous high‐latitude paleoclimate studies diverge on whether lake water 2 H‐enrichment outpaces leaf water 2 H‐enrichment under arid conditions (Balascio et al., 2013, 2016), or vice versa (Kjellman et al., 2020; Thomas et al., 2018; Zhao et al., 2022).…”