Inferring Phytoplankton, Terrestrial Plant and Bacteria Bulk δ¹³C Values from Compound Specific Analyses of Lipids and Fatty Acids.
Inferring Phytoplankton, Terrestrial Plant and Bacteria Bulk δ¹³C Values from Compound Specific Analyses of Lipids and Fatty Acids.
复制标题
从脂质和脂肪酸的化合物特定分析中推断出浮游植物，陆生植物和细菌的大量Δ³C值。
DOI：
10.1371/journal.pone.0133974
复制
发表时间：
2015
期刊：
影响因子：
3.7
通讯作者：
Brett MT
中科院分区：
文献类型：
--
作者：
Taipale SJ;Peltomaa E;Hiltunen M;Jones RI;Hahn MW;Biasi C;Brett MT
水生生态学中的稳定同位素混合模型需要浮游植物和细菌等食物网末端成员的δ 13 C值，但很少能够直接测量这些值。因此，迫切需要改进的方法来估算混合悬浮物中浮游植物、细菌和陆源碎屑的δ 13 C比值。我们确定了脂质、磷脂和生物标志物脂肪酸的δ 13 C值，并使用这些值计算了8种浮游植物、5种细菌分类群和3种陆地有机物（2棵树和1棵草）的全细胞δ 13 C值的同位素差异。浮游植物的脂质含量（9.5±4.0%）高于细菌（7.3±0.8%）和陆地物质（3.9±1.7%）。结果表明，浮游植物、细菌和陆源物质的δ 13 C值符合系统发育分类，总脂、磷脂和脂肪酸的δ 13 C值之间具有较强的相关性。在浮游植物中，绿藻和蓝藻的生物标志物脂肪酸与总生物量之间的同位素差平均为-10.7 1. 1 ‰，隐藻、硅藻和硅藻的生物标志物脂肪酸与总生物量之间的同位素差平均为-6.1 1. 7 ‰。对于异养细菌以及I型和II型甲烷氧化细菌，我们的结果显示，生物标志物脂肪酸和总生物量之间的δ 13 C差异分别为-1.3 1. 3 ‰、-8.0 4. 4 ‰和-3.4 1. 4 ‰。对于陆地物质，同位素差异平均为-6.6 1. 2 ‰。基于这些结果，总脂质和生物标志物脂肪酸的δ 13 C值可以用于确定大量浮游植物、细菌或陆生物质的δ 13 C值，其不确定度为± 1.4‰（即，所有样品的同位素差异的合并SD）。我们的结论是，当特定化合物的稳定同位素分析变得更广泛，δ 13 C值的测定选定的生物标志物脂肪酸加上建立同位素差异，提供了一个有前途的方法来确定特定类群的散装δ 13 C值的浮游植物，细菌，和陆地碎屑嵌入混合悬浮物。
Stable isotope mixing models in aquatic ecology require δ13C values for food web end members such as phytoplankton and bacteria, however it is rarely possible to measure these directly. Hence there is a critical need for improved methods for estimating the δ13C ratios of phytoplankton, bacteria and terrestrial detritus from within mixed seston. We determined the δ13C values of lipids, phospholipids and biomarker fatty acids and used these to calculate isotopic differences compared to the whole-cell δ13C values for eight phytoplankton classes, five bacterial taxa, and three types of terrestrial organic matter (two trees and one grass). The lipid content was higher amongst the phytoplankton (9.5±4.0%) than bacteria (7.3±0.8%) or terrestrial matter (3.9±1.7%). Our measurements revealed that the δ13C values of lipids followed phylogenetic classification among phytoplankton (78.2% of variance was explained by class), bacteria and terrestrial matter, and there was a strong correlation between the δ13C values of total lipids, phospholipids and individual fatty acids. Amongst the phytoplankton, the isotopic difference between biomarker fatty acids and bulk biomass averaged -10.7±1.1‰ for Chlorophyceae and Cyanophyceae, and -6.1±1.7‰ for Cryptophyceae, Chrysophyceae and Diatomophyceae. For heterotrophic bacteria and for type I and type II methane-oxidizing bacteria our results showed a -1.3±1.3‰, -8.0±4.4‰, and -3.4±1.4‰ δ13C difference, respectively, between biomarker fatty acids and bulk biomass. For terrestrial matter the isotopic difference averaged -6.6±1.2‰. Based on these results, the δ13C values of total lipids and biomarker fatty acids can be used to determine the δ13C values of bulk phytoplankton, bacteria or terrestrial matter with ± 1.4‰ uncertainty (i.e., the pooled SD of the isotopic difference for all samples). We conclude that when compound-specific stable isotope analyses become more widely available, the determination of δ13C values for selected biomarker fatty acids coupled with established isotopic differences, offers a promising way to determine taxa-specific bulk δ13C values for the phytoplankton, bacteria, and terrestrial detritus embedded within mixed seston.