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

作者：K. Hollister, Elizabeth K. Thomas, Martha K. Raynolds, Helga Bültmann, Jonathan H. Raberg, Gifford H. Miller, Julio Sepúlveda · 发表于：Journal of Geophysical Research Biogeosciences · 年份：2022 · DOI：10.1029/2022jg006903 · 被引用次数：33 · 研究领域：Climate change and permafrost、Geology and Paleoclimatology Research、Hydrocarbon exploration and reservoir analysis

Abstract Sedimentary plant wax δ 2 H values are common proxies for hydrology, a poorly constrained variable in the Arctic. However, it can be difficult to distinguish plant waxes derived from aquatic versus terrestrial plants, causing uncertainty in climate interpretations. We test the hypothesis that Arctic lake sediment mid‐ and long‐chain plant waxes derive from aquatic and terrestrial plants, respectively. We compare n ‐alkanoic acid and n ‐alkane chain‐length distributions and n ‐alkanoic acid δ 2 H and δ 13 C values of the 29 most abundant modern plant taxa to those for soils, water filtrates, and lake sediments in the Qaupat Lake (QPT) catchment, Nunavut, Canada. Chain length distributions are variable among terrestrial plants, but similar and dominated by mid‐chain waxes among submerged/floating aquatic plants. Sedimentary wax distributions are similar to those in submerged/floating aquatic plants and to Salix spp., which are among the most abundant terrestrial plants in the QPT catchment. Mid‐chain n‐ alkanoic acid δ 2 H values are similar in sediments and submerged/floating aquatic plants, but 50‰ lower than Salix spp. In contrast, sedimentary long‐chain n ‐alkanoic acid δ 2 H values fall between those for submerged/floating aquatic plants and Salix spp. We therefore infer that mid‐chain waxes in QPT are primarily from aquatic plants, whereas long‐chain waxes are from a mix of terrestrial and aquatic plants. In Arctic lakes like QPT, terrestrial wax transport via le...