Organic carbon budget for the Gulf of Bothnia

In this perspective article, I argue that dissolved organic carbon occupies a central role in the functioning of lake ecosystems, comparable in importance to that played by nutrients. Because lakes receive so much dissolved organic carbon from the terrestrial landscape, its accumulation in water bodies usually represents the largest pool of lacustrine organic matter within the water column. The transformation of even a small fraction of this external carbon by the microbial community can alter significantly the metabolic balance of lake ecosystems, simultaneously releasing carbon dioxide to the atmosphere and burying organic carbon in lake sediments. At the landscape level, even if they occupy a small fraction of the landscape, lakes play a surprisingly important role in the regional carbon budget, particularly when considered at the appropriate temporal scale.

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The carbon budget of the Baltic Sea

Biogeosciences ◽

10.5194/bg-8-3219-2011 ◽

2011 ◽

Vol 8 (11) ◽

pp. 3219-3230 ◽

Cited By ~ 63

Author(s):

K. Kuliński ◽

J. Pempkowiak

Keyword(s):

Organic Carbon ◽

Baltic Sea ◽

Carbon Budget ◽

The Other ◽

Minor Importance ◽

The Baltic Sea ◽

Sources And Sinks ◽

The North ◽

The North Sea ◽

The Baltic

Abstract. This paper presents the results of a comprehensive study of the Baltic Sea carbon budget. The Baltic Sea is very much influenced by terrestrial carbon input. Rivers are the largest carbon source, and their input amounts to 10.90 Tg C yr−1 (Tg = 1012 g) with a 37.5% contribution of organic carbon. On the other hand, carbon is effectively exported from the Baltic to the North Sea (7.67 Tg C yr−1) and is also buried in bottom sediments (2.73 Tg C yr−1). The other sources and sinks of carbon are of minor importance. The net CO2 emission (1.05 Tg C yr−1) from the Baltic to the atmosphere was calculated as the closing term of the carbon budget presented here. There is a net loss of organic carbon, which indicates that the Baltic Sea is heterotrophic.

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An organic carbon budget for coastal Southern California determined by estimates of vertical nutrient flux, net community production and export

Deep Sea Research Part I Oceanographic Research Papers ◽

10.1016/j.dsr.2016.07.003 ◽

2016 ◽

Vol 116 ◽

pp. 49-76 ◽

Cited By ~ 11

Author(s):

William Z. Haskell ◽

Maria G. Prokopenko ◽

Douglas E. Hammond ◽

Rachel H.R. Stanley ◽

William M. Berelson ◽

...

Keyword(s):

Organic Carbon ◽

Southern California ◽

Carbon Budget ◽

Nutrient Flux ◽

Net Community Production ◽

Community Production

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Reviews and syntheses: Hidden forests, the role of vegetated coastal habitats in the ocean carbon budget

Biogeosciences ◽

10.5194/bg-14-301-2017 ◽

2017 ◽

Vol 14 (2) ◽

pp. 301-310 ◽

Cited By ~ 80

Author(s):

Carlos M. Duarte

Keyword(s):

Carbon Sequestration ◽

Organic Carbon ◽

Primary Production ◽

Deep Sea ◽

Carbon Budget ◽

Net Primary Production ◽

Global Ocean ◽

Coastal Habitats ◽

Global Carbon Budget ◽

Global Carbon

Abstract. Vegetated coastal habitats, including seagrass and macroalgal beds, mangrove forests and salt marshes, form highly productive ecosystems, but their contribution to the global carbon budget remains overlooked, and these forests remain hidden in representations of the global carbon budget. Despite being confined to a narrow belt around the shoreline of the world's oceans, where they cover less than 7 million km2, vegetated coastal habitats support about 1 to 10 % of the global marine net primary production and generate a large organic carbon surplus of about 40 % of their net primary production (NPP), which is either buried in sediments within these habitats or exported away. Large, 10-fold uncertainties in the area covered by vegetated coastal habitats, along with variability about carbon flux estimates, result in a 10-fold bracket around the estimates of their contribution to organic carbon sequestration in sediments and the deep sea from 73 to 866 Tg C yr−1, representing between 3 % and 1∕3 of oceanic CO2 uptake. Up to 1∕2 of this carbon sequestration occurs in sink reservoirs (sediments or the deep sea) beyond these habitats. The organic carbon exported that does not reach depositional sites subsidizes the metabolism of heterotrophic organisms. In addition to a significant contribution to organic carbon production and sequestration, vegetated coastal habitats contribute as much to carbonate accumulation as coral reefs do. While globally relevant, the magnitude of global carbon fluxes supported by salt-marsh, mangrove, seagrass and macroalgal habitats is declining due to rapid habitat loss, contributing to loss of CO2 sequestration, storage capacity and carbon subsidies. Incorporating the carbon fluxes' vegetated coastal habitats' support into depictions of the carbon budget of the global ocean and its perturbations will improve current representations of the carbon budget of the global ocean.

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Impact of dust deposition on carbon budget: a tentative assessment from a mesocosm approach

Biogeosciences ◽

10.5194/bg-11-5621-2014 ◽

2014 ◽

Vol 11 (19) ◽

pp. 5621-5635 ◽

Cited By ~ 27

Author(s):

C. Guieu ◽

C. Ridame ◽

E. Pulido-Villena ◽

M. Bressac ◽

K. Desboeufs ◽

...

Keyword(s):

Organic Carbon ◽

Atmospheric Deposition ◽

Mediterranean Sea ◽

Particulate Organic Carbon ◽

Dry Deposition ◽

Wet Deposition ◽

Carbon Budget ◽

Net Primary Production ◽

Saharan Dust ◽

Dust Deposition

Abstract. By bringing new nutrients and particles to the surface ocean, atmospheric deposition impacts biogeochemical cycles. The extent to which those changes are modifying the carbon balance in oligotrophic environments such as the Mediterranean Sea that receives important Saharan dust fluxes is unknown. The DUNE (DUst experiment in a low Nutrient, low chlorophyll Ecosystem) project provides the first attempt to evaluate the changes induced in the carbon budget of a large body of oligotrophic waters after simulated Saharan dust wet or dry deposition events, allowing us to measure (1) the metabolic fluxes while the particles are sinking and (2) the particulate organic carbon export. Here we report the results for the three distinct artificial dust seeding experiments simulating wet or dry atmospheric deposition onto large mesocosms (52 m3) that were conducted in the oligotrophic waters of the Mediterranean Sea in the summers of 2008 and 2010. Although heterotrophic bacteria were found to be the key players in the response to dust deposition, net primary production increased about twice in case of simulated wet deposition (that includes anthropogenic nitrogen). The dust deposition did not produce a shift in the metabolic balance as the tested waters remained net heterotrophic (i.e., net primary production to bacteria respiration ratio <1) and in some cases the net heterotrophy was even enhanced by the dust deposition. The change induced by the dust addition on the total organic carbon pool inside the mesocosm over the 7 days of the experiments, was a carbon loss dominated by bacteria respiration that was at least 5–10 times higher than any other term involved in the budget. This loss of organic carbon from the system in all the experiments was particularly marked after the simulation of wet deposition. Changes in biomass were mostly due to an increase in phytoplankton biomass but when considering the whole particulate organic carbon pool it was dominated by the organic carbon aggregated to the lithogenic particles still in suspension in the mesocosm at the end of the experiment. Assuming that the budget is balanced, the dissolved organic carbon (DOC) pool was estimated by the difference between the total organic carbon and the particulate organic carbon (POC) pool. The partitioning between dissolved and particulate organic carbon was dominated by the dissolved pool with a DOC consumption over 7 days of ∼1 μmol C L−1 d−1 (dry deposition) to ∼2–5 μmol C L−1 d−1 (wet deposition). This consumption in the absence of any allochthonous inputs in the closed mesocosms meant a small <10% decrease of the initial DOC stock after a dry deposition but a ∼30–40% decrease of the initial DOC stock after wet deposition. After wet deposition, the tested waters, although dominated by heterotrophy, were still maintaining a net export (corrected from controls) of particulate organic carbon (0.5 g in 7 days) even in the absence of allochthonous carbon inputs. This tentative assessment of the changes in carbon budget induced by a strong dust deposition indicates that wet deposition by bringing new nutrients has higher impact than dry deposition in oligotrophic environments. In the western Mediterranean Sea, the mineral dust deposition is dominated by wet deposition and one perspective of this work is to extrapolate our numbers to time series of deposition during similar oligotrophic conditions to evaluate the overall impact on the carbon budget at the event and seasonal scale in the surface waters of the northwestern Mediterranean Sea. These estimated carbon budgets are also highlighting the key processes (i.e., bacterial respiration) that need to be considered for an integration of atmospheric deposition in marine biogeochemical modeling.

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Towards an improved organic carbon budget for the western Barents Sea shelf

Climate of the Past ◽

10.5194/cp-10-569-2014 ◽

2014 ◽

Vol 10 (2) ◽

pp. 569-587 ◽

Cited By ~ 9

Author(s):

I. Pathirana ◽

J. Knies ◽

M. Felix ◽

U. Mann

Keyword(s):

Organic Carbon ◽

Sea Ice ◽

Primary Productivity ◽

Carbon Budget ◽

Barents Sea ◽

Carbon Accumulation ◽

The Arctic ◽

Sediment Surface ◽

Organic Facies ◽

Facies Modelling

Abstract. There is generally a lack of knowledge on how marine organic carbon accumulation is linked to vertical export and primary productivity patterns in the Arctic Ocean. Despite the fact that annual primary production in the Arctic has increased as a consequence of shrinking sea ice, its effect on flux, preservation, and accumulation of organic carbon is still not well understood. In this study, a multi-proxy geochemical and organic-sedimentological approach is coupled with organic facies modelling, focusing on regional calculations of carbon cycling and carbon burial on the western Barents Shelf between northern Scandinavia and Svalbard. OF-Mod 3-D, an organic facies modelling software tool, is used to reconstruct and quantify the marine and terrestrial organic carbon fractions and to make inferences about marine primary productivity changes across the marginal ice zone (MIZ). By calibrating the model against an extensive set of sediment surface samples, we improve the Holocene organic carbon budget for ice-free and seasonally ice-covered areas in the western Barents Sea. The results show that higher organic carbon accumulation rates in the MIZ are best explained by enhanced surface water productivity compared to ice-free regions, implying that shrinking sea ice may reveal a significant effect on the overall organic carbon storage capacity of the western Barents Sea shelf.

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Estimation of atmospheric total organic carbon (TOC) – paving the path towards carbon budget closure

Atmospheric Chemistry and Physics ◽

10.5194/acp-19-459-2019 ◽

2019 ◽

Vol 19 (1) ◽

pp. 459-471 ◽

Cited By ~ 6

Author(s):

Mingxi Yang ◽

Zoë L. Fleming

Keyword(s):

Carbon Dioxide ◽

Organic Carbon ◽

Total Organic Carbon ◽

Organic Compounds ◽

Carbon Budget ◽

Dimethyl Sulfide ◽

Anthropogenic Activity ◽

Heated Sample ◽

Diurnal Variability ◽

Marine Air

Abstract. The atmosphere contains a rich variety of reactive organic compounds, including gaseous volatile organic carbon (VOCs), carbonaceous aerosols, and other organic compounds at varying volatility. Here we present a novel and simple approach to measure atmospheric non-methane total organic carbon (TOC) based on catalytic oxidation of organics in bulk air to carbon dioxide. This method shows little sensitivity towards humidity and near 100 % oxidation efficiencies for all VOCs tested. We estimate a best-case hourly precision of 8 ppb C during times of low ambient variability in carbon dioxide, methane, and carbon monoxide (CO). As proof of concept of this approach, we show measurements of TOC+CO during August–September 2016 from a coastal city in the southwest United Kingdom. TOC+CO was substantially elevated during the day on weekdays (occasionally over 2 ppm C) as a result of local anthropogenic activity. On weekends and holidays, with a mean (standard error) of 102 (8) ppb C, TOC+CO was lower and showed much less diurnal variability. TOC+CO was significantly lower when winds were coming off the Atlantic Ocean than when winds were coming off land if we exclude the weekday daytime. By subtracting the estimated CO from TOC+CO, we constrain the mean (uncertainty) TOC in Atlantic-dominated air masses to be around 23 (±≥8) ppb C during this period. A proton-transfer-reaction mass spectrometer (PTR-MS) was deployed at the same time, detecting a large range of organic compounds (oxygenated VOCs, biogenic VOCs, aromatics, dimethyl sulfide). The total speciated VOCs from the PTR-MS, denoted here as Sum(VOC), amounted to a mean (uncertainty) of 12 (±≤3) ppb C in marine air. Possible contributions from a number of known organic compounds present in marine air that were not detected by the PTR-MS are assessed within the context of the TOC budget. Finally, we note that the use of a short, heated sample tube can improve the transmission of organics to the analyzer, while operating our system alternately with and without a particle filter should enable a better separation of semi-volatile and particulate organics from the VOCs within the TOC budget. Future concurrent measurements of TOC, CO, and a more comprehensive range of speciated VOCs would enable a better characterization and understanding of the atmospheric organic carbon budget.

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