Cycling of black carbon in the ocean

Coppola, Alysha I.; Druffel, Ellen R. M.

doi:10.1002/2016gl068574

Cited by 106 publications

(180 citation statements)

References 41 publications

(70 reference statements)

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“…Our results are comparable to those reported in earlier studies. Surface seawater was reported to contain 2.6% and 0.9% of DBC from the Gulf of Mexico and the Atlantic Ocean [ Dittmar, ] and 4.2 ± 1.0% DBC in the northeast Pacific [ Coppola and Druffel , ]. Also, using the SPE and BPCA methods, Wagner et al [] reported that 3.2–6.6% of the riverine DOC pool was DBC in the Cache La Poudre River in the Colorado Rocky Mountains (USA).…”

Section: Resultsmentioning

confidence: 99%

Two black carbon pools transported by the Changjiang and Huanghe Rivers in China

Wang

Druffel

et al. 2016

Global Biogeochemical Cycles

112

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Major rivers play important roles in transporting large amounts of terrestrial organic matter from land to the ocean each year, and the organic matter carried by rivers contains a significant fraction of black carbon (BC). A recent study estimated that 0.027 Gt of BC is transported in the dissolved phase by rivers each year, which accounts for ~10% of the global flux of dissolved organic carbon. The relative sources of this large amount of riverine dissolved black carbon (DBC) from biomass burning (young, modern 14C) and fossil fuel (old, 14C free) combustion are not known. We present radiocarbon measurements of BC in both dissolved and particulate phases transported by the Changjiang and Huanghe Rivers, the two largest rivers in China, during 2015. We show that two, distinct BC pools (young and old) were carried by the rivers. The DBC pool was much younger than the particulate BC (PBC) pool. Mass balance calculations indicate that most (78–85%) of the DBC in the Changjiang and Huanghe Rivers was derived from biomass burning, and only 15–22% was from fossil fuel combustion. In contrast, PBC from biomass burning and fossil fuel combustion were approximately equal in these two rivers. Export of PBC and DBC by the rivers are decoupled, and fluxes of PBC were 4.1 and 6.7 times higher than DBC in the Changjiang and Huanghe Rivers, respectively. The 14C age differences of the two BC pools suggest that BC derived from biomass burning and fossil fuel combustion are mobilized in different phases and on different time scales in these rivers.

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Section: Resultsmentioning

confidence: 99%

Two black carbon pools transported by the Changjiang and Huanghe Rivers in China

Wang

Druffel

et al. 2016

Global Biogeochemical Cycles

112

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“…Oceanic DBC is generally more radiocarbon depleted (Δ 14 C age: 18,000–23,000 yr; Ziolkowski and Druffel ; Coppola and Druffel ) than the bulk DOC (Δ 14 C age: 4000–6000 yr; Druffel et al ). Previous studies observed anomalously high DOC concentrations in the deep Southern Ocean (Druffel and Bauer ; Follett et al ), especially in the Indian Ocean Sector adjacent to Prydz Bay (Bercovici and Hansell ).…”

Section: Discussionmentioning

confidence: 99%

Transport of dissolved black carbon from the Prydz Bay Shelf, Antarctica to the deep Southern Ocean

Fang

Yang

Chen

et al. 2018

Limnology & Oceanography

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Dissolved black carbon (DBC) is one of the largest pools of molecularly identifiable carbon in the ocean. In the deep ocean, DBC appears to persist for millennia, whereas it can be rapidly degraded by sunlight in surface waters. In Antarctica, the downward transport of dense shelf water (DSW) exports a massive volume of water to the deep Southern Ocean each year. If this sinking DSW is enriched in DBC, it may allow a route for DBC to escape degradation by sunlight in the surface ocean and become sequestered in the deep waters of the global ocean. To investigate this possibility, we quantified dissolved organic carbon (DOC), DBC, and ancillary properties in the waters of an Antarctic shelf sea (Prydz Bay) and adjacent waters. DBC concentrations in Prydz Bay DSW (1.2 ± 0.3 μmol L−1) were elevated compared to those in circumpolar deep water (0.49 ± 0.07 μmol L−1). The water column distribution of DBC in Prydz Bay suggested that sediments were the main source of DBC in DSW. A mixing model incorporating seawater oxygen isotopes (H2δ18O) indicated that Prydz Bay DSW transported DBC and DOC into the deep Southern Ocean. We estimate that the downward transport of DSW from Prydz Bay could contribute 4–9% (66–150 Gg yr−1) and 2–4% (3700–8500 Gg yr−1) to the DBC and DOC concentrations in Antarctic Bottom Water, respectively. Thus, the downward transport of DBC along the Antarctic shelf/slope is likely a significant source of DBC to the deep waters of the Southern and Global Ocean.

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“…To our knowledge, this study is the first to report compound‐specific δ 13 C values for DBC in riverine and oceanic waters. Although previous studies have performed BPCA‐specific radiocarbon (Δ 14 C) measurements on pooled BPCAs derived from marine DBC, stable carbon isotopic compositions were not reported (Ziolkowski and Druffel ; Coppola and Druffel ). Carbon isotopes have been used to assess the dynamic sources and processing of DOC in aquatic systems and have revealed the differences in reactivity and cycling of subcomponents within the bulk DOC pool (Bauer et al ; Raymond and Bauer ).…”

Section: Discussion and Recommendationsmentioning

confidence: 99%

“…Using BPCA‐specific measurements, ancient ( 14 C‐depleted) DBC was found to exist in marine surface waters (∼ 4800 14 C yr old) and in the deep ocean (∼ 23,000 14 C yr old; Coppola and Druffel ). Dual isotopic analyses have been successfully employed to resolve and quantify the sources of bulk DOC in aquatic systems (Raymond and Bauer ; Bauer ), and a similar approach could be taken to track movement, degradation, and fate of BC in the environment.…”

Section: Discussion and Recommendationsmentioning

confidence: 99%

Online quantification and compound‐specific stable isotopic analysis of black carbon in environmental matrices via liquid chromatography‐isotope ratio mass spectrometry

Wagner

Brandes

Goranov

et al. 2017

Limnology & Ocean Methods

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Black carbon (BC) is derived from the burning of biomass, a considerable portion of organic matter across terrestrial and marine ecosystems, and a major contributor to global carbon cycles. The benzenepolycarboxylic acid method, which converts condensed aromatic BC structures to molecular markers (BPCAs), has been widely adopted for environmental BC assessments. We present a novel analytical method for the online separation, quantification, and determination of compound‐specific stable carbon isotopes of individual BPCAs via high performance liquid chromatography‐stable carbon isotope ratio mass spectrometry (HPLC‐C‐IRMS). To assess δ13C values of environmental BC, the HPLC‐C‐IRMS method was applied to a variety of samples (soil, char, aerosol, and dissolved organic matter). The method reliably measured amounts and δ13C values of benzenepentacarboxylic acid (B5CA) and mellitic acid (B6CA) over a range of 8.3–130 μmol‐C of organic matter oxidized. BPCA‐specific δ13C values deviated from bulk OC δ13C values for different sample types. However, the stable carbon isotopic composition of B5CA and B6CA was found to be generally correlated with that of bulk organic carbon. The stable isotopic compositions of environmental samples covered a wide dynamic range, indicating BC‐specific δ13C values will be useful for tracking BC sources and processing. For instance, the BPCAs derived from marine dissolved organic matter (DOM) were enriched in 13C relative to BPCAs from riverine DOM, suggesting rivers are not the only source of dissolved black carbon to the oceans.

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Cycling of black carbon in the ocean

Cited by 106 publications

References 41 publications

Two black carbon pools transported by the Changjiang and Huanghe Rivers in China

Two black carbon pools transported by the Changjiang and Huanghe Rivers in China

Transport of dissolved black carbon from the Prydz Bay Shelf, Antarctica to the deep Southern Ocean

Online quantification and compound‐specific stable isotopic analysis of black carbon in environmental matrices via liquid chromatography‐isotope ratio mass spectrometry

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