A largely invariant marine dissolved organic carbon reservoir across Earth's history

Marine dissolved organic carbon (DOC), the largest pool of reduced carbon in the oceans, plays an important role in the global carbon cycle and contributes to the regulation of atmospheric oxygen and carbon dioxide abundances. Despite its importance in global biogeochemical cycles, the long-term history of the marine DOC reservoir is poorly constrained. Nonetheless, significant changes to the size of the oceanic DOC reservoir through Earth’s history have been commonly invoked to explain changes to ocean chemistry, carbon cycling, and marine ecology. Here, we present a revised view of the evolution of marine DOC concentrations using a mechanistic carbon cycle model that can reproduce DOC concentrations in both oxic and anoxic modern environments. We use this model to demonstrate that the overall size of the marine DOC reservoir has likely undergone very little variation through Earth’s history, despite major changes in the redox state of the ocean–atmosphere system and the nature and efficiency of the biological carbon pump. A relatively static marine DOC reservoir across Earth’s history renders it unlikely that major changes in marine DOC concentrations have been responsible for driving massive repartitioning of surface carbon or the large carbon isotope excursions observed in Earth’s stratigraphic record and casts doubt on previously hypothesized links between marine DOC levels and the emergence and radiation of early animals.

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Phanerozoic Oxygen

10.23943/princeton/9780691145020.003.0011 ◽

2017 ◽

Author(s):

Donald Eugene Canfield

Keyword(s):

Oxygen Consumption ◽

Organic Carbon ◽

Sea Level ◽

Time Scale ◽

Atmospheric Oxygen ◽

Sea Level Change ◽

Oxygen Production ◽

Level Change ◽

History Of ◽

Geologic Processes

This chapter discusses the modeling of the history of atmospheric oxygen. The most recently deposited sediments will also be the most prone to weathering through processes like sea-level change or uplift of the land. Thus, through rapid recycling, high rates of oxygen production through the burial of organic-rich sediments will quickly lead to high rates of oxygen consumption through the exposure of these organic-rich sediments to weathering. From a modeling perspective, rapid recycling helps to dampen oxygen changes. This is important because the fluxes of oxygen through the atmosphere during organic carbon and pyrite burial, and by weathering, are huge compared to the relatively small amounts of oxygen in the atmosphere. Thus, all of the oxygen in the present atmosphere is cycled through geologic processes of oxygen liberation (organic carbon and pyrite burial) and consumption (weathering) on a time scale of about 2 to 3 million years.

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Characterization of bacterioplankton communities and quantification of organic carbon pools off the Galapagos Archipelago under contrasting environmental conditions

PeerJ ◽

10.7717/peerj.5984 ◽

2018 ◽

Vol 6 ◽

pp. e5984 ◽

Cited By ~ 4

Author(s):

Nataly Carolina Guevara Campoverde ◽

Christiane Hassenrück ◽

Pier Luigi Buttigieg ◽

Astrid Gärdes

Keyword(s):

Organic Carbon ◽

Carbon Cycle ◽

Dissolved Organic Carbon ◽

Bacterial Communities ◽

Carbon Pools ◽

Aggregate Formation ◽

Galapagos Archipelago ◽

Carbon Concentrations ◽

Bacterioplankton Communities

Bacteria play a crucial role in the marine carbon cycle, contributing to the production and degradation of organic carbon. Here, we investigated organic carbon pools, aggregate formation, and bacterioplankton communities in three contrasting oceanographic settings in the Galapagos Archipelago. We studied a submarine CO2 vent at Roca Redonda (RoR), an upwelling site at Bolivar Channel (BoC) subjected to a weak El Niño event at the time of sampling in October 2014, as well as a site without volcanic or upwelling influence at Cowley Islet (CoI). We recorded physico-chemical parameters, and quantified particulate and dissolved organic carbon, transparent exopolymeric particles, and the potential of the water to form larger marine aggregates. Free-living and particle-attached bacterial communities were assessed via 16S rRNA gene sequencing. Both RoR and BoC exhibited temperatures elevated by 1–1.5 °C compared to CoI. RoR further experienced reduced pH between 6.8 and 7.4. We observed pronounced differences in organic carbon pools at each of the three sites, with highest dissolved organic carbon concentrations at BoC and RoR, and highest particulate organic carbon concentrations and aggregate formation at BoC. Bacterioplankton communities at BoC were dominated by opportunistic copiotrophic taxa, such as Alteromonas and Roseobacter, known to thrive in phytoplankton blooms, as opposed to oligotrophic taxa dominating at CoI, such as members of the SAR11 clade. Therefore, we propose that bacterial communities were mainly influenced by the availability of organic carbon at the investigated sites. Our study provides a comprehensive characterization of organic carbon pools and bacterioplankton communities, highlighting the high heterogeneity of various components of the marine carbon cycle around the Galapagos Archipelago.

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The Seasonal Flux and Fate of Dissolved Organic Carbon Through Bacterioplankton in the Western North Atlantic

Frontiers in Microbiology ◽

10.3389/fmicb.2021.669883 ◽

2021 ◽

Vol 12 ◽

Author(s):

Nicholas Baetge ◽

Michael J. Behrenfeld ◽

James Fox ◽

Kimberly H. Halsey ◽

Kristina D. A. Mojica ◽

...

Keyword(s):

Organic Carbon ◽

Dissolved Organic Carbon ◽

North Atlantic ◽

Phytoplankton Bloom ◽

North Atlantic Ocean ◽

Net Primary Production ◽

Deep Ocean ◽

Carbon Demand ◽

Carbon Pump ◽

Biological Carbon Pump

The oceans teem with heterotrophic bacterioplankton that play an appreciable role in the uptake of dissolved organic carbon (DOC) derived from phytoplankton net primary production (NPP). As such, bacterioplankton carbon demand (BCD), or gross heterotrophic production, represents a major carbon pathway that influences the seasonal accumulation of DOC in the surface ocean and, subsequently, the potential vertical or horizontal export of seasonally accumulated DOC. Here, we examine the contributions of bacterioplankton and DOM to ecological and biogeochemical carbon flow pathways, including those of the microbial loop and the biological carbon pump, in the Western North Atlantic Ocean (∼39–54°N along ∼40°W) over a composite annual phytoplankton bloom cycle. Combining field observations with data collected from corresponding DOC remineralization experiments, we estimate the efficiency at which bacterioplankton utilize DOC, demonstrate seasonality in the fraction of NPP that supports BCD, and provide evidence for shifts in the bioavailability and persistence of the seasonally accumulated DOC. Our results indicate that while the portion of DOC flux through bacterioplankton relative to NPP increased as seasons transitioned from high to low productivity, there was a fraction of the DOM production that accumulated and persisted. This persistent DOM is potentially an important pool of organic carbon available for export to the deep ocean via convective mixing, thus representing an important export term of the biological carbon pump.

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Globally Carbon Cycle and Measurement of Dissolved Organic Carbon in Sea Water.

Journal of Environmental Chemistry ◽

10.5985/jec.4.1 ◽

1994 ◽

Vol 4 (1) ◽

pp. 1-18

Author(s):

Yoshimi SUZUKI ◽

Hiroshi ITO

Keyword(s):

Organic Carbon ◽

Carbon Cycle ◽

Dissolved Organic Carbon ◽

Sea Water

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Minimal Evidence of Permafrost Carbon in Siberia’s Kolyma River

Eos ◽

10.1029/2021eo163244 ◽

2021 ◽

Vol 102 ◽

Author(s):

Terri Cook

Keyword(s):

Climate Change ◽

Organic Carbon ◽

Carbon Cycle ◽

Dissolved Organic Carbon ◽

Arctic Rivers ◽

New Research ◽

Minimal Evidence ◽

Kolyma River

New research finds that Arctic rivers currently transport limited permafrost-derived dissolved organic carbon, which has implications for understanding the region’s changing carbon cycle—and its potential to accelerate climate change.

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Carbon cycle perturbation and mercury anomalies in terrestrial Oceanic Anoxic Event 1b from Jiuquan Basin, NW China

Geological Society London Special Publications ◽

10.1144/sp521-2021-149 ◽

2022 ◽

pp. SP521-2021-149

Author(s):

Xiangdong Zhao ◽

Daran Zheng ◽

He Wang ◽

Yanan Fang ◽

Naihua Xue ◽

...

Keyword(s):

Organic Carbon ◽

Carbon Cycle ◽

Central Italy ◽

Lacustrine Sediments ◽

Terrestrial Ecosystem ◽

Western Tethys ◽

Oceanic Anoxic Event ◽

Anoxic Event ◽

Carbon Reservoir ◽

Global Carbon

AbstractThe Oceanic Anoxic Event (OAE) 1b is well documented in western Tethys, however, records in Eurasia are still lacking. Here, we carried out high-resolution organic carbon isotope (δ13Corg), total organic carbon (TOC) contents and mercury (Hg) concentrations analysis of the lacustrine sediments from the Xiagou and Zhonggou formations in the Hanxiagou section, Jiuquan Basin, northwestern China. The lacustrine δ13Corg curve presents three stages of negative excursions above the basalt layer dated at 112.4 ± 0.3 Ma in the lowermost Zhonggou Formation. The three negative δ13Corg excursions, well corresponded with the three subevents (Kilian, Paquier, and Leenhardt) of the OAE1b in Poggio le Guaine (central Italy), Vocontian Basin (SE France) and St Rosa Canyon (NE Mexico) sections, supporting the record of the terrestrial OAE 1b in the Jiuquan Basin. Five mercury enrichment (ME) intervals in Hg/TOC ratios were recognized, indicating that the pulsed volcanism from the southern Kerguelen Plateau likely triggered the OAE 1b. However, the decoupling between NIE shifts and mercury enrichments signifying other carbon reservoir (with no link to mercury) probably contributed to the global carbon cycle perturbation during the OAE 1b period. Our results provide direct evidence to link the OAE 1b and terrestrial ecosystem in the Eurasia.

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Watershed dissolved organic carbon transport: a modeling approach combining water travel times and reactivity continuum

10.5194/egusphere-egu2020-9033 ◽

2020 ◽

Author(s):

Giulia Grandi ◽

Enrico Bertuzzo

Keyword(s):

Organic Carbon ◽

Carbon Cycle ◽

Dissolved Organic Carbon ◽

Transport Model ◽

Terrestrial Ecosystems ◽

Riverine Ecosystems ◽

Doc Concentration ◽

Tightly Coupled ◽

Reactivity Continuum ◽

Carbon Degradation

<p>Although their contribution was neglected in the past, inland waters play a significant role in the carbon cycle and affect CO<sub>2</sub> global balance. Streams and rivers are now considered not only as pipelines but as active reactors able to collect and transform carbon from terrestrial ecosystems trough drainage, erosion, deposition and respiration. Quantifying the transfer of carbon from the terrestrial to the riverine ecosystems is thus of crucial importance to fully appreciate carbon cycle at the watershed, regional and global scales. Such transfer is largely controlled by the processes occurring in the critical zone where the carbon and water cycles are tightly coupled. Previous studies investigated how hydrological drivers can affect Dissolved Organic Carbon (DOC) concentration in streams highlighting an hysteretic and unsteady behavior for the DOC-discharge relationship. In this study, we focus on the drainage flux from hillslopes to stream and river networks during rainfall events combining a transport model for water and a model of carbon degradation in soil. Using high-frequency records of chloride and DOC in Plynlimon catchments (UK), we employ the recently developed StorAge Selection (SAS) theory to evaluate water travel time and its partition as evapotranspiration, discharge and storage. We combine this approach with the reactivity continuum &#160;theory to model &#160;carbon degradation along the flow paths using a gamma-distribution as probability density function of the quality. The developed model can thus predict not only the flux of DOC released from hillslopes but also its quality (i.e. lability). We also show how the variability of the DOC-discharge relationship can partially be explained by hydrological fluctuations.</p>

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Authigenic Carbonate and the History of the Global Carbon Cycle

Science ◽

10.1126/science.1229578 ◽

2013 ◽

Vol 339 (6119) ◽

pp. 540-543 ◽

Cited By ~ 236

Author(s):

Daniel P. Schrag ◽

John. A. Higgins ◽

Francis A. Macdonald ◽

David T. Johnston

Keyword(s):

Carbon Cycle ◽

Carbon Isotope ◽

Atmospheric Oxygen ◽

Carbon Isotopic Composition ◽

Minor Component ◽

Authigenic Carbonate ◽

Carbon Isotopic ◽

History Of ◽

A Minor ◽

Global Carbon

We present a framework for interpreting the carbon isotopic composition of sedimentary rocks, which in turn requires a fundamental reinterpretation of the carbon cycle and redox budgets over Earth's history. We propose that authigenic carbonate, produced in sediment pore fluids during early diagenesis, has played a major role in the carbon cycle in the past. This sink constitutes a minor component of the carbon isotope mass balance under the modern, high levels of atmospheric oxygen but was much larger in times of low atmospheric O2or widespread marine anoxia. Waxing and waning of a global authigenic carbonate sink helps to explain extreme carbon isotope variations in the Proterozoic, Paleozoic, and Triassic.

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First pan-Arctic assessment of dissolved organic carbon in lakes of the permafrost region

Biogeosciences ◽

10.5194/bg-18-3917-2021 ◽

2021 ◽

Vol 18 (12) ◽

pp. 3917-3936

Author(s):

Lydia Stolpmann ◽

Caroline Coch ◽

Anne Morgenstern ◽

Julia Boike ◽

Michael Fritz ◽

...

Keyword(s):

Climate Change ◽

Organic Carbon ◽

Soil Organic Carbon ◽

Carbon Cycle ◽

Dissolved Organic Carbon ◽

Significant Relationship ◽

Global Carbon Cycle ◽

Doc Concentration ◽

Global Carbon ◽

Permafrost Regions

Abstract. Lakes in permafrost regions are dynamic landscape components and play an important role for climate change feedbacks. Lake processes such as mineralization and flocculation of dissolved organic carbon (DOC), one of the main carbon fractions in lakes, contribute to the greenhouse effect and are part of the global carbon cycle. These processes are in the focus of climate research, but studies so far are limited to specific study regions. In our synthesis, we analyzed 2167 water samples from 1833 lakes across the Arctic in permafrost regions of Alaska, Canada, Greenland, and Siberia to provide first pan-Arctic insights for linkages between DOC concentrations and the environment. Using published data and unpublished datasets from the author team, we report regional DOC differences linked to latitude, permafrost zones, ecoregions, geology, near-surface soil organic carbon contents, and ground ice classification of each lake region. The lake DOC concentrations in our dataset range from 0 to 1130 mg L−1 (10.8 mg L−1 median DOC concentration). Regarding the permafrost regions of our synthesis, we found median lake DOC concentrations of 12.4 mg L−1 (Siberia), 12.3 mg L−1 (Alaska), 10.3 mg L−1 (Greenland), and 4.5 mg L−1 (Canada). Our synthesis shows a significant relationship between lake DOC concentration and lake ecoregion. We found higher lake DOC concentrations at boreal permafrost sites compared to tundra sites. We found significantly higher DOC concentrations in lakes in regions with ice-rich syngenetic permafrost deposits (yedoma) compared to non-yedoma lakes and a weak but significant relationship between soil organic carbon content and lake DOC concentration as well as between ground ice content and lake DOC. Our pan-Arctic dataset shows that the DOC concentration of a lake depends on its environmental properties, especially on permafrost extent and ecoregion, as well as vegetation, which is the most important driver of lake DOC in this study. This new dataset will be fundamental to quantify a pan-Arctic lake DOC pool for estimations of the impact of lake DOC on the global carbon cycle and climate change.

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