Global scale production of brGDGTs by benthic marine bacteria: Implication for developing ocean bottom environmental proxies

Xiao, Wenjie; Xu, Yunping; Jiang, Lin; Zeng, Zhiyu; Liu, Yongsheng; Zhang, Hongrui; Zhang, Chuanlun

doi:10.1016/j.gloplacha.2022.103783

Cited by 12 publications

(17 citation statements)

References 52 publications

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“…In environmental brGDGTs, the number of alkyl‐chain methylations correlates strongly with temperature in numerous sample types, including soils (e.g., Naafs, Inglis, et al, 2017 ), peats (e.g., Naafs, Gallego‐Sala, et al, 2017 ), lake sediments (e.g., Martínez‐Sosa et al, 2021 ; Raberg et al, 2021 ), and marine sediments (Xiao et al, 2022 ). These changes in the number of methylations are commonly quantified by calculating indices such as the methylation index of branched tetraethers (MBT; Weijers et al, 2007 ; and MBT′ 5Me De Jonge, Hopmans, et al, 2014 ) or by grouping brGDGTs into the structurally based methylation (Meth) set (Raberg et al, 2021 ) for comparisons with environmental temperatures.…”

Section: Introductionmentioning

confidence: 99%

Production of diverse brGDGTs by Acidobacterium Solibacter usitatus in response to temperature, pH, and O₂ provides a culturing perspective on brGDGT proxies and biosynthesis

et al. 2022

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Branched glycerol dialkyl glycerol tetraethers (brGDGTs) are bacterial membrane lipids that are frequently employed as paleoenvironmental proxies because of the strong empirical correlations between their relative abundances and environmental temperature and pH. Despite the ubiquity of brGDGTs in modern and paleoenvironments, the source organisms of these enigmatic compounds have remained elusive, requiring paleoenvironmental applications to rely solely on observed environmental correlations. Previous laboratory and environmental studies have suggested that the globally abundant bacterial phylum of the Acidobacteria may be an important brGDGT producer in nature. Here, we report on experiments with a cultured Acidobacterium, Solibacter usitatus, that makes a large portion of its cellular membrane (24 ± 9% across all experiments) out of a structurally diverse set of tetraethers including the common brGDGTs Ia, IIa, IIIa, Ib, and IIb. Solibacter usitatus was grown across a range of conditions including temperatures from 15 to 30°C, pH from 5.0 to 6.5, and O2 from 1% to 21%, and demonstrated pronounced shifts in the degree of brGDGT methylation across these growth conditions. The temperature response in culture was in close agreement with trends observed in published environmental datasets, supporting a physiological basis for the empirical relationship between brGDGT methylation number and temperature. However, brGDGT methylation at lower temperatures (15 and 20°C) was modulated by culture pH with higher pH systematically increasing the degree of methylation. In contrast, pH had little effect on brGDGT cyclization, supporting the hypothesis that changes in bacterial community composition may underlie the link between cyclization number and pH observed in environmental samples. Oxygen concentration likewise affected brGDGT methylation highlighting the potential for this environmental parameter to impact paleotemperature reconstruction. Low O2 culture conditions further resulted in the production of uncommon brGDGT isomers that could be indicators of O2 limitation. Finally, the production of brGTGTs (trialkyl tetraethers) in addition to the previously discovered iso‐C15‐based mono‐ and diethers in S. usitatus suggests a potential biosynthetic pathway for brGDGTs that uses homologs of the archaeal tetraether synthase (Tes) enzyme for tetraether synthesis from diethers.

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Section: Introductionmentioning

confidence: 99%

Production of diverse brGDGTs by Acidobacterium Solibacter usitatus in response to temperature, pH, and O₂ provides a culturing perspective on brGDGT proxies and biosynthesis

et al. 2022

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“…The cross-validation results showed that the correct classification probability for different groups reached 83.2% (Supplementary Table 1), indicating the interpretation of discriminant function was effective and robust. Recent studies have found that the degree of cyclization of marine in situ produced brGDGTs increases with rising pH, while the degree of methylation increases with decreasing temperature 40,41 . The results indicate that tuffs display unique brGDGT distribution characteristics, potentially produced under low temperature and slightly high pH conditions.…”

Section: Discussionmentioning

confidence: 99%

Chemolithotrophic biosynthesis of organic carbon associated with volcanic ash in the Mariana Trough, Pacific Ocean

Longman

et al. 2023

Commun Earth Environ

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Volcanic ash is a major component of marine sediment, but its effect on the deep-sea carbon cycle remains enigmatic. Here, we analyzed mineralogical compositions and glycerol dialkyl glycerol tetraether (GDGT) membrane lipids in submarine tuffs from the Mariana Trough, demonstrating a fraction of organic carbon associated with volcanic ash is produced in situ. This likely derives from chemolithotrophic communities supported by alteration of volcanic material. Tuff GDGTs are characterized by enrichment of branched GDGTs, as in chemolithotrophic communities. Scanning electron microscope, Raman spectrum and nano secondary ion mass spectrometry analysis demonstrates organic carbon exists around secondary heamatite veins in the altered mafic minerals, linking mineral alteration to chemolithotrophic biosynthesis. We estimate organic carbon production of between 0.7 − 3.7 × 1011 g if all the chemical energy produced by ash alteration was fully utilized by microorganisms. Therefore, the chemolithotrophic ecosystem maintained by ash alteration likely contributes considerably to organic carbon production in the seafloor.

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“…Figures 4a and 4b show that the >63 μm fractionated sediments exhibit comparatively higher TMBR′ and BIT values, whereas the finer grains (<63 μm fractions) have relatively lower TMBR′ values. The IIIa/IIa ratio is used to discriminate the origin of terrestrial‐ and marine‐derived branched‐GDGTs (Y. Liu et al., 2021; M. Wang et al., 2023; W. Xiao et al., 2016, 2020, 2022). Relatively higher IIIa/IIa ratios are found in the finer grains (Figure 4c).…”

Section: Discussionmentioning

confidence: 99%

“…Biomarker‐based indicators have been applied in the SYS for marine biogeochemical investigations (H. Ge et al., 2014; Y. Jia et al., 2019; Mei et al., 2015; L. Wang et al., 2011; P. Wu et al., 2016; X. Wu et al., 2018; Xing et al., 2009), especially those based on alkenones and iso‐GDGTs (Y. Liu et al., 2021; Tao et al., 2012; W. Xiao et al., 2022; Xing, Tao, et al., 2011; Xing et al., 2015; Y. Zhang et al., 2019; X. Zhao et al., 2013). Our previous studies demonstrated that hydrodynamic processes in the SYS alter the distribution of sedimentary organic matter (R. Bao et al., 2016; R. Bao, van der Voort, et al., 2018; R. Bao, Blattmann, et al., 2019).…”

Section: Introductionmentioning

confidence: 99%

Spatial Discrepancy of Hydrodynamics‐Driven Impacts on Organic Biomarkers Deposition and ′ and TEX₈₆ Temperature Proxies Applications

Xiao

Xing

Chen

et al. 2023

Global Biogeochemical Cycles

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There is evidence that sedimentary organic matter is prone to lateral transport under hydrodynamic processes before its final deposition on the seafloor, restricting the applicability of molecular proxies. In this study, we examine the abundances of marine and terrestrial biomarkers in bulk and the grain‐size fractionated samples (<20, 20–63, and >63 μm fractions) from surface sediments in the South Yellow Sea to decipher the spatial influences of hydrodynamic processes on the biomarker distributions and molecule‐proxies' applications. Our results show that spatial deviations between proxies‐derived sea surface temperature (SST; the U37K ${\mathrm{U}}_{37}^{\mathrm{K}}$′ and TEX86 indexes) and satellite‐derived annual mean SST may result from the lateral transportation of the alkenones and isoprenoid Glycerol Dialkyl Glycerol Tetraethers driven by dominated nearshore coastal currents. We propose a spatial‐SST correction approach to obtain more accurate SST information by removing the hydrodynamically introduced SST bias. Our investigations imply that hydrodynamic processes could be an important factor for controlling the spatial distribution of biomarkers in the ocean, further influencing the applications of biomarker‐based proxies for paleo‐environmental reconstruction. We suggest that this investigation would shed new light on the biogeochemical dynamics of sedimentary organic carbon pump in the shallow ocean, particularly in the passive continental marginal seas with strong hydrodynamic conditions.

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Global scale production of brGDGTs by benthic marine bacteria: Implication for developing ocean bottom environmental proxies

Cited by 12 publications

References 52 publications

Production of diverse brGDGTs by Acidobacterium Solibacter usitatus in response to temperature, pH, and O₂ provides a culturing perspective on brGDGT proxies and biosynthesis

Production of diverse brGDGTs by Acidobacterium Solibacter usitatus in response to temperature, pH, and O₂ provides a culturing perspective on brGDGT proxies and biosynthesis

Chemolithotrophic biosynthesis of organic carbon associated with volcanic ash in the Mariana Trough, Pacific Ocean

Spatial Discrepancy of Hydrodynamics‐Driven Impacts on Organic Biomarkers Deposition and ′ and TEX₈₆ Temperature Proxies Applications

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Global scale production of brGDGTs by benthic marine bacteria: Implication for developing ocean bottom environmental proxies

Cited by 12 publications

References 52 publications

Production of diverse brGDGTs by Acidobacterium Solibacter usitatus in response to temperature, pH, and O2 provides a culturing perspective on brGDGT proxies and biosynthesis

Production of diverse brGDGTs by Acidobacterium Solibacter usitatus in response to temperature, pH, and O2 provides a culturing perspective on brGDGT proxies and biosynthesis

Chemolithotrophic biosynthesis of organic carbon associated with volcanic ash in the Mariana Trough, Pacific Ocean

Spatial Discrepancy of Hydrodynamics‐Driven Impacts on Organic Biomarkers Deposition and ′ and TEX86 Temperature Proxies Applications

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Production of diverse brGDGTs by Acidobacterium Solibacter usitatus in response to temperature, pH, and O₂ provides a culturing perspective on brGDGT proxies and biosynthesis

Production of diverse brGDGTs by Acidobacterium Solibacter usitatus in response to temperature, pH, and O₂ provides a culturing perspective on brGDGT proxies and biosynthesis

Spatial Discrepancy of Hydrodynamics‐Driven Impacts on Organic Biomarkers Deposition and ′ and TEX₈₆ Temperature Proxies Applications