Global trends of ocean CO2 sink and ocean acidification: an observation-based reconstruction of surface ocean inorganic carbon variables

Iida, Yosuke; Takatani, Yusuke; Kojima, Atsushi; Ishii, Masao

doi:10.1007/s10872-020-00571-5

Cited by 102 publications

(119 citation statements)

References 89 publications

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“…The integrated air-sea CO 2 flux in each SST regime was calculated by multiplying the mean monthly air-sea CO 2 flux by the numbers of months in each SST regime. The monthly air-sea CO 2 fluxes from April 2014 to May 2019 within the area between 23.5~24.5°N and 132.5~140.5°E were estimated using the p CO 2 diagnostic model 63 . The ocean of the study region acted as CO 2 sink through most periods except for the SST > 28 °C regime (Supplementary Fig.…”

Section: Methodsmentioning

confidence: 99%

Nanomolar phosphate supply and its recycling drive net community production in the subtropical North Pacific

et al. 2021

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Seasonal drawdown of dissolved inorganic carbon (DIC) in the subtropical upper ocean makes a significant contribution to net community production (NCP) globally. Although NCP requires macronutrient supply, surface macronutrients are chronically depleted, and their supply has been unable to balance the NCP demand. Here, we report nanomolar increases in surface nitrate plus nitrite (N+N, ~20 nM) and phosphate (PO4, ~15 nM) from summer to winter in the western subtropical North Pacific. Molar ratios of upward fluxes of DIC:N+N:PO4 to the euphotic zone (< 100 m) were in near-stoichiometric balance with microbial C:N:P ratios (107~243:16~35:1). Comparison of these upward influxes with other atmospheric and marine sources demonstrated that total supply is largely driven by the other sources for C and N (93~96%), but not for P (10%), suggesting that nanomolar upward supply of P and its preferential recycling play a vital role in sustaining the NCP.

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Section: Methodsmentioning

confidence: 99%

Nanomolar phosphate supply and its recycling drive net community production in the subtropical North Pacific

et al. 2021

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“…Monthly-mean fire emissions are used from GFEDv4s (van der Werf et al, 2017) for simulating the CO2 fire tracer. Sea-air CO2 fluxes are taken from an upscaling model of shipboard measurements of pCO2 (referred to here as TT09: Takahashi et al, 2009), and an empirical model of the Japan Meteorological Agency (JMA; Iida et al, 2021) for simulating CO2 ocn tracers. The seasonal cycle for TT09 sea-air exchange flux is stationary, like that of the CASA, over the analysis period, while the JMA oceanic CO2 fluxes vary interannually, as in the case of VISIT.…”

Section: A Priori Co2 Simulationsmentioning

confidence: 99%

Estimated regional CO<sub>2</sub> flux and uncertainty based on an ensemble of atmospheric CO<sub>2</sub> inversions

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Niwa

et al. 2021

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Abstract. Global and regional sources and sinks of carbon across the earth’s surface have been studied extensively using atmospheric carbon dioxide (CO2) observations and chemistry-transport model (ACTM) simulations (top-down/inversion method). However, the uncertainties in the regional flux (+ve: source to the atmosphere; −ve: sink on land/ocean) distributions remain unconstrained mainly due to the lack of sufficient high-quality measurements covering the globe in all seasons and the uncertainties in model simulations. Here, we use a suite of 16 inversion cases, derived from a single transport model (MIROC4-ACTM) but different sets of a priori (bottom-up) terrestrial biosphere and oceanic fluxes, as well as prior flux and observational data uncertainties (50 sites) to estimate CO2 fluxes for 84 regions over the period 2000–2020. The ensemble inversions provide a mean flux field that is consistent with the global CO2 growth rate, land and ocean sink partitioning of −2.9 ± 0.3 (±1σ uncertainty on mean) and −1.6 ± 0.2 PgC yr−1, respectively, for the period 2011–2020 (without riverine export correction), offsetting about 22–33 % and 16–18 % of global fossil-fuel CO2 emissions. Aggregated fluxes for 15 land regions compare reasonably well with the best estimations for (approx. 2000–2009) given by the REgional Carbon Cycle Assessment and Processes (RECCAP), and all regions appeared as a carbon sink over 2011–2020. Interannual variability and seasonal cycle in CO2 fluxes are more consistently derived for different prior fluxes when a greater degree of freedom is given to the inversion system (greater prior flux uncertainty). We have evaluated the inversion fluxes using independent aircraft and surface measurements not used in the inversions, which raises our confidence in the ensemble mean flux rather than an individual inversion. Differences between 5-year mean fluxes show promises and capability to track flux changes under ongoing and future CO2 emission mitigation policies.

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“…Elevated atmospheric, and therefore oceanic, CO 2 concentrations also cause ocean acidification (Doney et al, 2009). This reduction of pH, currently at a global average of about 0.002 pH units per year (Bates et al, 2014;Iida et al, 2021), occurs as CO 2 dissolves in the oceans to form carbonic acid (H 2 CO 3 ), which readily dissociates to bicarbonate (HCO 3 − ), carbonate (CO 3 2− ), and H + . "Impacts of unmitigated ocean acidification are estimated to represent a loss to the world economy of more than US $1 trillion annually by 2100" (Secretariat of the Convention on Biological Diversity, 2014).…”

Section: Introductionmentioning

confidence: 99%

Industry Partnership: Lab on Chip Chemical Sensor Technology for Ocean Observing

et al. 2021

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We introduce for the first time a new product line able to make high accuracy measurements of a number of water chemistry parameters in situ: i.e., submerged in the environment including in the deep sea (to 6,000 m). This product is based on the developments of in situ lab on chip technology at the National Oceanography Centre (NOC), and the University of Southampton and is produced under license by Clearwater Sensors Ltd., a start-up and industrial partner in bringing this technology to global availability and further developing its potential. The technology has already been deployed by the NOC, and with their partners worldwide over 200 times including to depths of ∼4,800 m, in turbid estuaries and rivers, and for up to a year in seasonally ice-covered regions of the arctic. The technology is capable of making accurate determinations of chemical and biological parameters that require reagents and which produce an electrical, absorbance, fluorescence, or luminescence signal. As such it is suitable for a wide range of environmental measurements. Whilst further parameters are in development across this partnership, Nitrate, Nitrite, Phosphate, Silicate, Iron, and pH sensors are currently available commercially. Theses sensors use microfluidics and optics combined in an optofluidic chip with electromechanical valves and pumps mounted upon it to mix water samples with reagents and measure the optical response. An overview of the sensors and the underlying components and technologies is given together with examples of deployments and integrations with observing platforms such as gliders, autonomous underwater vehicles and moorings.

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Global trends of ocean CO2 sink and ocean acidification: an observation-based reconstruction of surface ocean inorganic carbon variables

Cited by 102 publications

References 89 publications

Nanomolar phosphate supply and its recycling drive net community production in the subtropical North Pacific

Nanomolar phosphate supply and its recycling drive net community production in the subtropical North Pacific

Estimated regional CO<sub>2</sub> flux and uncertainty based on an ensemble of atmospheric CO<sub>2</sub> inversions

Industry Partnership: Lab on Chip Chemical Sensor Technology for Ocean Observing

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Global trends of ocean CO2 sink and ocean acidification: an observation-based reconstruction of surface ocean inorganic carbon variables

Cited by 102 publications

References 89 publications

Nanomolar phosphate supply and its recycling drive net community production in the subtropical North Pacific

Nanomolar phosphate supply and its recycling drive net community production in the subtropical North Pacific

Estimated regional CO&lt;sub&gt;2&lt;/sub&gt; flux and uncertainty based on an ensemble of atmospheric CO&lt;sub&gt;2&lt;/sub&gt; inversions

Industry Partnership: Lab on Chip Chemical Sensor Technology for Ocean Observing

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Estimated regional CO<sub>2</sub> flux and uncertainty based on an ensemble of atmospheric CO<sub>2</sub> inversions