Phylogeny, alkenone profiles and ecology of Isochrysidales subclades in saline lakes: Implications for paleosalinity and paleotemperature reconstructions

doi:10.1016/j.gca.2021.11.001

	Phylogeny, alkenone profiles and ecology of Isochrysidales subclades in saline lakes: Implications for paleosalinity and paleotemperature reconstructions
	Yao, Yuan 5,6,7; Zhao, Jiaju 6; Vachula, Richard S.4; Liao, Sian 3; Li, Gaoyuan 2; Pearson, Emma J.1; Huang, Yongsong 5
刊名	GEOCHIMICA ET COSMOCHIMICA ACTA
	2022-01-15
卷号	317 页码:472-487
关键词	Alkenones Alkenoates Group 2 Isochrysidales Paleosalinity proxy Paleotemperature proxy Saline lakes
ISSN号	0016-7037
DOI	10.1016/j.gca.2021.11.001
通讯作者	Huang, Yongsong(yongsong_huang@brown.edu)
英文摘要	Long-chain alkenones (LCAs) produced by phylogenetically classified Groups 1 and 3 Isochrysidales are increasingly used for paleotemperature and/or paleosalinity reconstructions in oligohaline lakes and marine environments. However, there are considerable difficulties in the paleoenvironmental interpretation of LCAs from Group 2 Isochrysidales thriving in saline lakes. The biggest challenge lies in our poor understanding of the complexity and ecological niches of individual Group 2 subclades in saline lakes. Here, we perform comprehensive analysis of haptophyte-specific 18S rRNA sequences and distributions of LCAs, and long-chain alkenoates (LCEs) in surface sediments and suspended particulate matter (SPM) from 37 saline lakes in northern China. These lakes span a large salinity gradient from 0.5 to 308%. Combined with published genomic data of Group 2 Isochrysidales, our phylogenetic analysis reveals three Group 2 subclades occupying distinct ecological niches: one ice-related bloomer Group 2i and two warm-season bloomers Groups 2w1 and 2w2. Group 2i, the earliest seasonal bloomer, frequently co-occurs with Group 2w1 in sediments from saline lakes with relatively low to intermediate salinity waters, whereas Group 2w2 blooms in hypersaline waters. Based on existing data, C-39:4 methyl alkenone is a chemotaxonomic biomarker for Group 2i. %C-3(7:)4 (relative abundance of C(3)(7:)(4 )to the total C-37 alkenones) values in the three Group subclades follow the order: Group 2i > Group 2w2 > Group 2w1. The %C(37:4 )in sediment cores of saline lakes does not directly record past salinity changes, but instead reflects variable contributions in production by these three subclades. This could indirectly and partially reflect overall salinity changes in some lakes dominated by Groups 2i and 2w1, but can be more complicated in lakes dominated by other assemblages. For our sites, we also demonstrate that direct use of C(37 )alkenone unsaturation indices (U-37(K), U-37(K'), and U-37(K '')) for paleotemperature reconstructions in saline lakes is generally not feasible, except for cases where alkenone-producing Isochrysidales are dominated by one single species/subclade and seasonal production effects can be circumvented. We propose two possible alternative proxies for paleotemperature reconstructions in saline lakes: 1) unsaturation ratios of C-41 and C-42 alkenones, as these compounds are predominantly produced by a limited number of Group 2 species, such as Isochrysis nuda (Liao et al., 2020) 2) C38Et/C36OEt ratio (ratio of C-38 ethyl alkenones and C-36 ethyl alkenoates), which appears to have similar temperature sensitivity for Groups 2w1 and 2w2, in lakes with no Group 2i inputs. Our study provides new insights into the phylogenetic classifications of Group 2 Isochrysidales and their ecological/environmental niches, which are fundamental for more quantitative and rigorous applications of LCAs and LCEs in saline lakes as paleosalinity and paleotemperature proxies. (C) 2021 Elsevier Ltd. All rights reserved.
资助项目	National Natural Science Foundation of China[42073070] ; National Natural Science Foundation of China[41702187] ; U.S. National Science Foundation[EAR-1122749] ; U.S. National Science Foundation[PLR-1503846] ; U.S. National Science Foundation[EAR-1502455] ; U.S. National Science Foundation[EAR-1762431] ; Fundamental Research Funds for the Central Universities[xxj032020004] ; Swiss Federal Institue of Technology
WOS关键词	LONG-CHAIN-ALKENONES ; UNSATURATED ALKENONE ; TEMPERATURE-CHANGES ; GROWTH TEMPERATURE ; DISTRIBUTIONS ; LACUSTRINE ; HAPTOPHYTE ; SEDIMENTS ; CALIBRATION ; QINGHAI
WOS研究方向	Geochemistry & Geophysics
语种	英语
出版者	PERGAMON-ELSEVIER SCIENCE LTD
WOS记录号	WOS:000744072000004
资助机构	National Natural Science Foundation of China ; U.S. National Science Foundation ; Fundamental Research Funds for the Central Universities ; Swiss Federal Institue of Technology
内容类型	期刊论文
源URL	[http://ir.ieecas.cn/handle/361006/17397]
专题	地球环境研究所_古环境研究室
通讯作者	Huang, Yongsong
作者单位	1.Newcastle Univ, Sch Geog Polit & Sociol, Newcastle Upon Tyne NE1 7RU, Tyne & Wear, England 2.China Univ Geosci, State Key Lab Biogeol & Environm Geol, Beijing 100083, Peoples R China 3.Brown Univ, Dept Chem, Providence, RI 02912 USA 4.Coll William & Mary, Dept Geol, Williamsburg, VA 23185 USA 5.Brown Univ, Dept Earth Environm & Planetary Sci, Providence, RI 02912 USA 6.Chinese Acad Sci, Inst Earth Environm, State Key Lab Loess & Quaternary Geol, Xian 710061, Peoples R China 7.Xi An Jiao Tong Univ, Inst Global Environm Change, Xian 710054, Peoples R China
推荐引用方式 GB/T 7714	Yao, Yuan,Zhao, Jiaju,Vachula, Richard S.,et al. Phylogeny, alkenone profiles and ecology of Isochrysidales subclades in saline lakes: Implications for paleosalinity and paleotemperature reconstructions[J]. GEOCHIMICA ET COSMOCHIMICA ACTA,2022,317:472-487.
APA	Yao, Yuan.,Zhao, Jiaju.,Vachula, Richard S..,Liao, Sian.,Li, Gaoyuan.,...&Huang, Yongsong.(2022).Phylogeny, alkenone profiles and ecology of Isochrysidales subclades in saline lakes: Implications for paleosalinity and paleotemperature reconstructions.GEOCHIMICA ET COSMOCHIMICA ACTA,317,472-487.
MLA	Yao, Yuan,et al."Phylogeny, alkenone profiles and ecology of Isochrysidales subclades in saline lakes: Implications for paleosalinity and paleotemperature reconstructions".GEOCHIMICA ET COSMOCHIMICA ACTA 317(2022):472-487.