Radiocarbon age of different photoreactive fractions of freshwater dissolved organic matter

Ishikawa, Naoto F.; Butman, David; Raymond, Peter A.

doi:10.1016/j.orggeochem.2019.06.006

Cited by 6 publications

(5 citation statements)

References 30 publications

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“…Organic carbon also makes up a significant part of the oceanic carbon pool and can be divided into two main components: DOC (< 0.8µm in size) and POC (> 0.8µm in size) 237 . Studies using radiocarbon measurements of POC and DOC provide detailed insights into biogeochemical cycling in the ocean [238][239][240][241][242] . POC is produced in the surface ocean and is responsible for transporting carbon to the deep ocean and sediments; it retains the 14 C signature of the surface ocean [243][244][245] .…”

Section: [H2] Ocean Environmentmentioning

confidence: 99%

Radiocarbon dating

Hajdas

Ascough

Garnett

et al. 2021

Nat Rev Methods Primers

128

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Radiocarbon dating uses the decay of a radioactive isotope of carbon ( 14 C) to measure time and date objects containing carbon-bearing material. With a half-life of 5,700 ± 30 years, detection of 14 C is a useful tool for determining the age of a specimen formed over the last 55,000 years. In this Primer, we outline key advances in 14 C measurement and instrument capacity, as well as optimal sample selection and preparation. We discuss data processing,

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Section: [H2] Ocean Environmentmentioning

confidence: 99%

Radiocarbon dating

Hajdas

Ascough

Garnett

et al. 2021

Nat Rev Methods Primers

128

View full text Add to dashboard Cite

show abstract

“…However, compound-specific 13 C analysis is an effective approach for discerning the source and fate of different DOM subcomponents, such as black carbon (Wagner et al, 2019). Similarly, 14 C measurements on different DOC molecular fractions has revealed that the apparent age and lability is not evenly distributed throughout the marine DOM pool (Follett et al, 2014;Close, 2019;Ishikawa et al, 2019). Thus, targeted isotopic analyses are needed to unveil drivers of DOM accumulation and apparent recalcitrance in the interior ocean.…”

Section: New Isotopic Approaches For Probing the Origin And Fate Of Oceanic Docmentioning

confidence: 99%

Soothsaying DOM: A Current Perspective on the Future of Oceanic Dissolved Organic Carbon

et al. 2020

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“…First, sunlight might completely oxidize relatively older DOC, leaving behind relatively younger DOC for microbes to respire. Studies exposing DOC from marine and lower‐latitude freshwaters to high doses of UV light have found that younger DOC is preferentially oxidized to CO 2 by sunlight (Beaupré & Druffel, 2012; Beaupré et al., 2007; Ishikawa et al., 2019). However, for permafrost DOC exposed to environmentally‐relevant, lower doses of UV and visible light, the age of the DOC completely oxidized to CO 2 by light has been shown to be similar to the age of the bulk permafrost DOC (≤70‰, or ≤930 years, different from the bulk DOC; Bowen et al., 2020b).…”

Section: Discussionmentioning

confidence: 99%

Controls on the Respiration of Ancient Carbon Draining From Permafrost Soils Into Sunlit Arctic Surface Waters

Rieb,

Polik,

Ward

et al. 2024

JGR Biogeosciences

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The thawing of ancient organic carbon stored in arctic permafrost soils, and its oxidation to carbon dioxide (CO2, a greenhouse gas), is predicted to amplify global warming. However, the extent to which organic carbon in thawing permafrost soils will be released as CO2 is uncertain. A critical unknown is the extent to which dissolved organic carbon (DOC) from thawing permafrost soils is respired to CO2 by microbes upon export of freshly thawed DOC to both dark bottom waters and sunlit surface waters. In this study, we quantified the radiocarbon age and 13C composition of CO2 produced by microbial respiration of DOC that was leached from permafrost soils and either kept in the dark or exposed to ultraviolet and visible wavelengths of light. We show that permafrost DOC most labile to microbial respiration was as old or older (ages 4,000–11,000 a BP) and more 13C‐depleted than the bulk DOC in both dark and light‐exposed treatments, likely indicating respiration of old, 13C‐depleted lignin and lipid fractions of the permafrost DOC pool. Light exposure either increased, decreased, or had no effect on the magnitude of microbial respiration of old permafrost DOC relative to respiration in the dark, depending on both the extent of DOC oxidation during exposure to light and the wavelength of light. Together, these findings suggest that photochemical changes affecting the lability of permafrost DOC during sunlight exposure are an important control on the magnitude of microbial respiration of permafrost DOC in arctic surface waters.

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Radiocarbon age of different photoreactive fractions of freshwater dissolved organic matter

Cited by 6 publications

References 30 publications

Radiocarbon dating

Radiocarbon dating

Soothsaying DOM: A Current Perspective on the Future of Oceanic Dissolved Organic Carbon

Controls on the Respiration of Ancient Carbon Draining From Permafrost Soils Into Sunlit Arctic Surface Waters

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