Taxon-specific hydrogen isotope signals in cultures and mesocosms facilitate ecosystem and hydroclimate reconstruction

Phytoplankton play a key role in biogeochemical cycles, impacting atmospheric and aquatic chemistry, food webs, and water quality. However, it remains challenging to reconstruct changes in algal community composition throughout the geologic past, as existing proxies are suitable only for a subset of taxa and/or influenced by degradation. Here, we investigate if compound-specific hydrogen isotope ratios (δ2H values) of common algal lipids can serve as (paleo)ecological indicators. First, we grew 20 species of algae – representing cyanobacteria, diatoms, dinoflagellates, green algae, and cryptomonads – in batch cultures under identical conditions and measured δ2H values of their lipids. Despite identical source water δ2H values, lipid δ2H values ranged from -455 ‰ to -52 ‰, and clustered according to taxonomic groups and chemical compound classes. In particular, green algae synthesized fatty acids with higher δ2H values than other taxa, cyanobacteria synthesized phytol with relatively low..., 20 species of phytoplankton were cultured under identical conditions in batch cultures. Biomass was filtered from cultured water. Mesocosm experiments were conducted in large-volume experimental ponds. Algal biomass was filtered from the water at three time points from each of the 20 experimental ponds. From both sample sets, lipids were extracted and purified, derivatized (methylated or acetylated) and compound-specific hydrogen isotope ratios of fatty acids, phytol, and sterols were measured by gas chromatography - isotope ratio mass spectrometry (GC-IRMS). Resulted lipid δ2H values are corrected for hydrogen added during derivatization. The isotopic composition of filtered water was determined by cavity ring-down spectroscopy., , # Data from: Taxon-specific hydrogen isotope signals in cultures and mesocosms facilitate ecosystem and hydroclimate reconstruction

[https://doi.org/10.5061/dryad.nvx0k6f0v ](https://doi.org/10.5061/dryad.nvx0k6f0v)

This data set contains hydrogen isotope ratios, expressed as d2H values, of algal lipids from two experiments: (1) batch cultures of different algal species under identical laboratory conditions and (2) large-volume mesocosms.

## Description of the data and file structure

File list: 

1. Algal_Culture_d2H.csv (results from batch cultures)
2. Pond_d2H.csv (results from large volume mesocosms)

Variable list:

* Species: Genus and species of cultured algae
* Group: Algal taxonomic group used for classifying and plotting data
* Class: Taxonomic class
* Number Replicate Cultures: Total number of replicate batch cultures
* d2H C16:0 FA: d2H value of C16:0 fatty acid (hexadecanoic acid; palmitic acid), expressed in per mil relative to Vienna Standard Mean Ocean Water (VSMOW)....

浮游植物在生物地球化学循环中发挥关键作用，可影响大气与水体化学、食物网结构及水环境质量。然而，重建地质历史时期藻类群落组成的变化仍颇具挑战，因现有代用指标仅适用于部分类群，且易受降解作用影响。本研究探讨常见藻类脂质的化合物特异性氢同位素比值（δ²H值）能否作为（古）生态指示物。
首先，我们在相同实验条件下的批量培养体系中培养了20种藻类，涵盖蓝细菌、硅藻、甲藻、绿藻及隐藻，并测定了其脂质的δ²H值。尽管所有实验的水源δ²H值一致，藻类脂质的δ²H值却分布于-455‰至-52‰之间，且按照类群与化合物类别聚类。具体而言，绿藻合成的脂肪酸δ²H值高于其他类群，蓝细菌合成的植醇δ²H值相对较低……本次研究共培养了20种浮游植物，均置于相同条件下的批量培养体系中。从培养水体中过滤收集藻类生物量。
本研究开展了大体积实验池塘的中型实验生态系统实验，从20个实验池塘的水体中分别于三个时间点过滤收集藻类生物量。从上述两组样本中，我们均提取并纯化了脂质，对其进行衍生化（甲基化或乙酰化），并通过气相色谱-同位素比值质谱法（GC-IRMS）测定了脂肪酸、植醇及固醇的化合物特异性氢同位素比值。所得脂质δ²H值已针对衍生化过程中引入的氢进行校正。过滤水体的同位素组成通过腔环衰荡光谱法测定。
# 数据来源：基于培养体系与中型实验生态系统的类群特异性氢同位素信号助力生态系统与水文气候重建
https://doi.org/10.5061/dryad.nvx0k6f0v
本数据集包含两类实验中藻类脂质的氢同位素比值（以δ²H值表示）：（1）相同实验室条件下不同藻类物种的批量培养实验；（2）大体积中型实验生态系统实验。
## 数据与文件结构说明
文件列表：
1. Algal_Culture_d2H.csv（批量培养实验结果）
2. Pond_d2H.csv（大体积中型实验生态系统实验结果）
变量列表：
* 物种：培养藻类的属名与种名
* 类群：用于数据分类与绘图的藻类分类类群
* 纲：分类学纲级单元
* 重复培养数：批量培养的总重复次数
* δ²H C16:0 FA：C16:0脂肪酸（十六烷酸，又称棕榈酸）的δ²H值，以相对于维也纳标准平均海水（VSMOW）的千分比表示……