Continental shelves as a variable but increasing global sink for atmospheric carbon dioxide

Laruelle, Goulven Gildas; Cai, Wei‐Jun; Hu, Xinping; Gruber, Nicolas; Mackenzie, Fred T.; Regnier, Pierre

doi:10.1038/s41467-017-02738-z

Cited by 161 publications

(202 citation statements)

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“…Laruelle et al () summarized two main mechanisms which have been described in the literature to explain the evolution of the continental shelf CO 2 sink. One mechanism relies on the timescales of air–water and shelf–open ocean exchanges of CO 2 , the other on the stimulation of the biological pump.…”

Section: Resultsmentioning

confidence: 99%

“…It should be noted, however, that the summer trend (or annual mean trend) in the NAW region may be different from the value determined in this study. Laruelle et al (2018) summarized two main mechanisms which have been described in the literature to explain the evolution of the continental shelf CO 2 sink. One mechanism relies on the timescales of air-water and shelf-open ocean exchanges of CO 2 , the other on the stimulation of the biological pump.…”

Section: Journal Of Geophysical Research: Biogeosciencesmentioning

confidence: 99%

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Trends of Ocean Acidification and pCO₂ in the Northern North Sea, 2003–2015

et al. 2019

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For continental shelf regions, the long‐term trend in sea surface carbon dioxide (CO2) partial pressure (pCO2) and rates of ocean acidification are not accurately known. Here, we investigate the decadal trend of observed wintertime pCO2 as well as computed wintertime pH and aragonite saturation state (Ωar) in the northern North Sea, using the first decade long monthly underway data from a voluntary observing ship covering the period 2004–2015. We also evaluate how seawater CO2 chemistry, in response to physical and biological processes, drives variations in the above parameters on seasonal and interannual timescales. In the northern North Sea, pCO2, pH, and Ωar are subject to strong seasonal variations with mean wintertime values of 375 ± 11 μatm, 8.17 ± 0.01, and 1.96 ± 0.05. Dissolved inorganic carbon is found to be the primary driver of both seasonal and interannual changes while total alkalinity and sea surface temperature have secondary effects that reduce the changes produced by dissolved inorganic carbon. Average interannual variations during winter are around 3%, 0.1%, and 2% for pCO2, pH, and Ωar, respectively and slightly larger in the eastern part of the study area (Skagerrak region) than in the western part (North Atlantic Water region). Statistically significant long‐term trends were found only in the North Atlantic Water region with mean annual rates of 2.39 ± 0.58 μatm/year, −0.0024 ± 0.001 year‐1, and −0.010 ± 0.003 year‐1 for pCO2, pH, and Ωar, respectively. The drivers of the observed trends as well as reasons for the lack of statistically significant trends in the Skagerrak region are discussed.

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Section: Resultsmentioning

confidence: 99%

Section: Journal Of Geophysical Research: Biogeosciencesmentioning

confidence: 99%

Trends of Ocean Acidification and pCO₂ in the Northern North Sea, 2003–2015

et al. 2019

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“…A complete attribution analysis of the F CO 2 seasonality on the global coastal regions is thus a goal that should be reachable in the near future. Moreover, long‐term trends and the interannual variability of global coastal CO 2 fluxes still remain poorly constrained (Laruelle et al, ). Coastal regions are subject to large interannual variations driven by riverine loading changes or climatic events such as the El Niño cycle.…”

Section: Concluding Remarks and Directions For Future Researchmentioning

confidence: 99%

The Spatiotemporal Dynamics of the Sources and Sinks of CO₂ in the Global Coastal Ocean

Roobaert

Laruelle

Landschützer

et al. 2019

Global Biogeochemical Cycles

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In contrast to the open ocean, the sources and sinks for atmospheric carbon dioxide (CO2) in the coastal seas are poorly constrained and understood. Here we address this knowledge gap by analyzing the spatial and temporal variability of the coastal air‐sea flux of CO2 (FCO2) using a recent high‐resolution (0.25°) monthly climatology for coastal sea surface partial pressure in CO2 (pCO2). Coastal regions are characterized by CO2 sinks at temperate and high latitudes and by CO2 sources at low latitude and in the tropics, with annual mean CO2 flux densities comparable in magnitude and pattern to those of the adjacent open ocean with the exception of river‐dominated systems. The seasonal variations in FCO2 are large, often exceeding 2 mol C m−2 year−1, a magnitude similar to the variations exhibited across latitudes. The majority of these seasonal variations stems from the air‐sea pCO2 difference, although changes in wind speed and sea ice cover can also be significant regionally. Globally integrated, the coastal seas act currently as a CO2 sink of −0.20 ± 0.02 Pg C year−1, with a more intense uptake occurring in summer because of the disproportionate influence of high‐latitude shelves in the Northern Hemisphere. Combined with estimates of the carbon sinks in the open ocean and the Arctic, this gives for the global ocean, averaged over the 1998 to 2015 period an annual net CO2 uptake of −1.7 ± 0.3 Pg C year−1.

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Section: Introductionmentioning

confidence: 99%

“…Globally, the uptake of CO 2 by shelf seas is thought to have increased over the last two decades as the difference between air and shelf water pCO 2 has increased (Laruelle et al, 2018). This trend may be driven by faster shelf-edge exchange and increased primary production due to anthropogenic nutrient inputs (Laruelle et al, 2018). Over longer timescales, coastal oceans may have shifted from pre-industrial CO 2 sources to modern CO 2 sinks due to increasing atmospheric CO 2 and increased nutrient inputs (Bauer et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

Carbon on the Northwest European Shelf: Contemporary Budget and Future Influences

et al. 2020

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A carbon budget for the northwest European continental shelf seas (NWES) was synthesized using available estimates for coastal, pelagic and benthic carbon stocks and flows. Key uncertainties were identified and the effect of future impacts on the carbon budget were assessed. The water of the shelf seas contains between 210 and 230 Tmol of carbon and absorbs between 1.3 and 3.3 Tmol from the atmosphere annually. Offshelf transport and burial in the sediments account for 60-100 and 0-40% of carbon outputs from the NWES, respectively. Both of these fluxes remain poorly constrained by observations and resolving their magnitudes and relative importance is a key research priority. Pelagic and benthic carbon stocks are dominated by inorganic carbon. Shelf sediments contain the largest stock of carbon, with between 520 and 1600 Tmol stored in the top 0.1 m of the sea bed. Coastal habitats such as salt marshes and mud flats contain large amounts of carbon per unit area but their total carbon stocks are small compared to pelagic and benthic stocks due to their smaller spatial extent. The large pelagic stock of carbon will continue to increase due to the rising concentration of atmospheric CO 2 , with associated pH decrease. Pelagic carbon stocks and flows are also likely to be significantly affected by increasing acidity and temperature, and circulation changes but the net impact is uncertain. Benthic carbon stocks will be affected by increasing temperature and acidity, and decreasing oxygen concentrations, although the net impact of these interrelated changes on carbon stocks is uncertain and a major knowledge gap. The impact of bottom trawling on benthic carbon stocks Frontiers in Marine Science | www.frontiersin.org 1 March 2020 | Volume 7 | Article 143Legge et al.Carbon on the Northwest European Shelf is unique amongst the impacts we consider in that it is widespread and also directly manageable, although its net effect on the carbon budget is uncertain. Coastal habitats are vulnerable to sea level rise and are strongly impacted by management decisions. Local, national and regional actions have the potential to protect or enhance carbon storage, but ultimately global governance, via controls on emissions, has the greatest potential to influence the long-term fate of carbon stocks in the northwestern European continental shelf.

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Continental shelves as a variable but increasing global sink for atmospheric carbon dioxide

Cited by 161 publications

References 58 publications

Trends of Ocean Acidification and pCO₂ in the Northern North Sea, 2003–2015

Trends of Ocean Acidification and pCO₂ in the Northern North Sea, 2003–2015

The Spatiotemporal Dynamics of the Sources and Sinks of CO₂ in the Global Coastal Ocean

Carbon on the Northwest European Shelf: Contemporary Budget and Future Influences

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Continental shelves as a variable but increasing global sink for atmospheric carbon dioxide

Cited by 161 publications

References 58 publications

Trends of Ocean Acidification and pCO2 in the Northern North Sea, 2003–2015

Trends of Ocean Acidification and pCO2 in the Northern North Sea, 2003–2015

The Spatiotemporal Dynamics of the Sources and Sinks of CO2 in the Global Coastal Ocean

Carbon on the Northwest European Shelf: Contemporary Budget and Future Influences

Contact Info

Product

Resources

About

Trends of Ocean Acidification and pCO₂ in the Northern North Sea, 2003–2015

Trends of Ocean Acidification and pCO₂ in the Northern North Sea, 2003–2015

The Spatiotemporal Dynamics of the Sources and Sinks of CO₂ in the Global Coastal Ocean