摘要
Primary productivity in the Antarctic aquatic environment with simple ecosystems is sensitive to climate and environmental fluctuations.We investigatedδ13C values for n-alkanoic acids derived from phototrophic organisms in a lacustrine sediment core(IIL3)to indicate primary productivity in ponds on Inexpressible Island in the western Ross Sea,Antarctica.Short-chain n-alkanoic acids(C14–C18)were abundant in the IIL3 sediment profile.The carbon isotope ratios of short-chain n-alkanoic acids in the sediment samples and floating microbial mats were similar,indicating that the short-chain n-alkanoic acids in the IIL3 sediment profile predominantly originated from phototrophic organisms.Theδ13C values for the short-chain n-alkanoic acids varied widely through the sediment profile,and 13C-enrichment of n-alkanoic acids was most likely related to high productivity due to carbon-limited conditions caused by enhanced photosynthetic efficiency.Theδ13C values for the n-alkanoic acids changed over the past 3200 years in similar ways to organic proxies for aquatic productivity(n-alkanoic acid and sterol sedimentary fluxes).C16 n-alkanoic acid was enriched in 13C in periods of high aquatic productivity~750–1650 and 3000–3200 a BP but depleted in 13C in periods of relatively low productivity~150–600 and 2500–3000 a BP.The results indicated that carbon isotope ratios of lipids from phototrophic organisms could be used as new proxies to reconstruct paleo-productivity in Antarctic lakes and ponds and therefore improve our understanding of past climate changes.
基金
supported by the National Natural Science Foundation of China (Grant nos. 42276240, 42206243, 41776188)
the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant no. XDB40000000)
the Shanghai Sailing Program (Grant no. 22YF1418800)
the China Postdoctoral Science Foundation (Grant no. 2022M712038)
the Shanghai Frontiers Science Center of Polar Science (SCOPS)
the Chinese Arctic and Antarctic Administration (CAA) for supporting the project
作者简介
Corresponding authors:CHEN Xin,ORCID:0000-0001-8560-8127,E-mail:xinchen1991@sjtu.edu.cn;Corresponding authors:LIU Xiaodong,ORCID:0000-0002-4333-8197,E-mail:ycx@ustc.edu.cn。
