The isotopes and biomarker approaches for identifying eroded organic matter sources in sediments: A review

Li, Chun; Li, Zhongwu; Berhe, Asmeret Asefaw; Hu, Bill X.

doi:10.1016/bs.agron.2020.02.005

Cited by 14 publications

(3 citation statements)

References 209 publications

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“…However, additional factors besides source discrepancy complicate interpretations of the nitrogen isotopic composition of organic matter in lake sediments, such as denitrification DIN in anoxic bottom water, seasonal changes in phytoplankton, and nitrogen fixation [16]. Thus, δ 15 Nassisted δ 13 C in organic matter tracing will provide more reliable results [39]. The nitrogen isotopic compositions (δ 15 N) in the Hulun Lake sediment profile show a large fluctuation range, varying from 5.89 to 7.97‰, with an average value of 7.05‰.…”

Section: N Distribution In Sediment Profilementioning

confidence: 99%

The Sources of Sedimentary Organic Matter Traced by Carbon and Nitrogen Isotopes and Environmental Effects during the Past 60 Years in a Shallow Steppe Lake in Northern China

Gao

Fan

Wang

et al. 2023

Water

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The organic matter of lake sediment plays an important role in paleolimnological reconstruction. Here, we report a detailed study of organic matter components (Corg%, N%, δ13C, δ15N) in a dated sediment core of Hulun Lake in northern China. Multiple mixing models based on the stoichiometric ratios and stable isotopic compositions were applied to quantify the contributions of organic matter sources in lake sediment. The results show that the organic matter in the sediments from Hulun Lake mainly comes from terrestrial organic matter: the proportion of terrestrial organic matter is more than 80%. The results of the SIAR mixing model further reveal that the proportions of terrestrial C3 plants-derived organic matter, soil organic matter, and lake plankton-derived organic matter were 76.0%, 13.9%, and 10.1%, respectively. The organic matter content of lake sediment from terrestrial sources began to increase significantly from 1980 onward, which is consistent with the growth in overgrazing in the Hulun Lake basin. The content of organic matter from endogenous lake-derived sources began to increase significantly after 2000 due to the nutrients gradually becoming concentrated in lake water, indicating that the reduction in rivers’ discharge and the downgrade of the lake water level were the immediate causes of the lake’s environmental deterioration during this period.

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Section: N Distribution In Sediment Profilementioning

confidence: 99%

The Sources of Sedimentary Organic Matter Traced by Carbon and Nitrogen Isotopes and Environmental Effects during the Past 60 Years in a Shallow Steppe Lake in Northern China

Gao

Fan

Wang

et al. 2023

Water

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“…They can be measured in bulk pools (i.e., soil, water, and gas) or in specific compounds (e.g., lignin) after separation, combustion, and/or reduction into target analyte gases (CO 2 , N 2 ), followed by analysis by isotope ratio mass spectrometry or cavity ring down spectroscopy. Bulk analyses integrate all biologic organic matter sources and isotope fractionation process, while analyses of specific compounds contribute information on their origin sources and fates (Benner et al 1987 ; Liu et al 2020 ). For example, δ 13 C values of lignin monomers—a biomarker of vascular plants—were used to quantify relative contribution of river, marsh, and marine sources in offshore sediments (Bianchi et al 1997 ).…”

Section: Carbon Poolsmentioning

confidence: 99%

Practical Guide to Measuring Wetland Carbon Pools and Fluxes

Bansal,

Creed,

Tangen

et al. 2023

Wetlands

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Wetlands cover a small portion of the world, but have disproportionate influence on global carbon (C) sequestration, carbon dioxide and methane emissions, and aquatic C fluxes. However, the underlying biogeochemical processes that affect wetland C pools and fluxes are complex and dynamic, making measurements of wetland C challenging. Over decades of research, many observational, experimental, and analytical approaches have been developed to understand and quantify pools and fluxes of wetland C. Sampling approaches range in their representation of wetland C from short to long timeframes and local to landscape spatial scales. This review summarizes common and cutting-edge methodological approaches for quantifying wetland C pools and fluxes. We first define each of the major C pools and fluxes and provide rationale for their importance to wetland C dynamics. For each approach, we clarify what component of wetland C is measured and its spatial and temporal representativeness and constraints. We describe practical considerations for each approach, such as where and when an approach is typically used, who can conduct the measurements (expertise, training requirements), and how approaches are conducted, including considerations on equipment complexity and costs. Finally, we review key covariates and ancillary measurements that enhance the interpretation of findings and facilitate model development. The protocols that we describe to measure soil, water, vegetation, and gases are also relevant for related disciplines such as ecology. Improved quality and consistency of data collection and reporting across studies will help reduce global uncertainties and develop management strategies to use wetlands as nature-based climate solutions.

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“…The chemical composition and structure of SOM were explored using target and nontarget analyses based on advanced organic mass spectrometry to identify molecular markers and reveal the molecular diversity. − Numerous molecular markers in SOM from different sources have been identified and studied with the help of target analysis. − According to the dynamic characteristics of molecular markers in soils, the behavior and fate of SOM from different sources during soil evolution and its feedbacks to environmental changes can be further estimated. However, limited molecular markers cannot fully reflect the complexity of SOM.…”

Section: Introductionmentioning

confidence: 99%

Advances in Molecular and Microscale Characterization of Soil Organic Matter: Current Limitations and Future Prospects

Huang

Luo

et al. 2022

Environ. Sci. Technol.

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Soil organic matter (SOM) comprises a continuum of organic materials from granular organic debris to small organic molecules and contains more organic carbon than global vegetation and the atmosphere combined. It has remarkable effects on soil ecological functions and the global carbon cycle as well as the fate of pollutants in the terrestrial ecosystem. Therefore, characterization of SOM is an important topic in soil science, ecology, and environmental science. Chemical complexity and spatial heterogeneity are by far the two biggest challenges to our understanding of SOM. Recent developments in analytical techniques and methods provide the opportunity to reveal SOM composition at the molecular level and to observe its distribution in soils at micro-and nanoscales, which have greatly improved our understanding of SOM. This paper reviews the outstanding advances in SOM characterization regarding these two issues from target and nontarget analyses comprising molecular marker analysis, ultrahigh-resolution mass spectrometry analysis, and in situ microscopic imaging techniques such as synchrotron-based spectromicroscopy, nanoscale secondary ion mass spectrometry, and emerging electron and optical microscopic imaging techniques. However, current techniques and methods remain far from unlocking the unknown properties of SOM. We systematically point out the limitations of the current technologies and outline the future prospects for comprehensive characterization of SOM at the molecular level and micro-and nanoscales, paying particular attention to issues of environmental concern.

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The isotopes and biomarker approaches for identifying eroded organic matter sources in sediments: A review

Cited by 14 publications

References 209 publications

The Sources of Sedimentary Organic Matter Traced by Carbon and Nitrogen Isotopes and Environmental Effects during the Past 60 Years in a Shallow Steppe Lake in Northern China

The Sources of Sedimentary Organic Matter Traced by Carbon and Nitrogen Isotopes and Environmental Effects during the Past 60 Years in a Shallow Steppe Lake in Northern China

Practical Guide to Measuring Wetland Carbon Pools and Fluxes

Advances in Molecular and Microscale Characterization of Soil Organic Matter: Current Limitations and Future Prospects

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