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Freeman, Natalie M.; Lovenduski, Nicole S.. |
Widespread ocean acidification is occurring as the ocean absorbs anthropogenic carbon dioxide from the atmosphere, threatening marine ecosystems, particularly the calcifying plankton that provide the base of the marine food chain and play a key role within the global carbon cycle. We use satellite estimates of particulate inorganic carbon (PIC), surface chlorophyll, and sea surface temperature to provide a first estimate of changing calcification rates throughout the Southern Ocean. From 1998 to 2014 we observe a 4% basin-wide reduction in summer calcification, with approximate to 9% reductions in large regions (approximate to 1 x 10(6) km(2)) of the Pacific and Indian sectors. Southern Ocean trends are spatially heterogeneous and primarily driven by... |
Tipo: Text |
Palavras-chave: Southern Ocean; Calcification; Particulate inorganic carbon; Carbonate ion; Antarctic polar front. |
Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00292/40371/38941.pdf |
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Landschuetzer, Peter; Ilyina, Tatiana; Lovenduski, Nicole S.. |
We use a neural network-based estimate of the sea surface partial pressure of CO2 (pCO(2)) derived from measurements assembled within the Surface Ocean CO2 Atlas to investigate the dominant modes of pCO(2) variability from 1982 through 2015. Our analysis shows that detrended and deseasonalized sea surface pCO(2) varies substantially by region and the respective frequencies match those from the major modes of climate variability (Atlantic Multidecadal Oscillation, Pacific Decadal Oscillation, multivariate ENSO index, Southern Annular Mode), suggesting a climate modulated air-sea exchange of CO2. We find that most of the regional pCO(2) variability is driven by changes in the ocean circulation and/or changes in biology, whereas the North Atlantic variability... |
Tipo: Text |
Palavras-chave: Ocean; CO2; Variability; Carbon; Climate; Observations. |
Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00675/78733/80972.pdf |
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Mckinley, Galen A.; Fay, Amanda R.; Eddebbar, Yassir A.; Gloege, Lucas; Lovenduski, Nicole S.. |
The ocean has absorbed the equivalent of 39% of industrial‐age fossil carbon emissions, significantly modulating the growth rate of atmospheric CO2 and its associated impacts on climate. Despite the importance of the ocean carbon sink to climate, our understanding of the causes of its interannual‐to‐decadal variability remains limited. This hinders our ability to attribute its past behavior and project its future. A key period of interest is the 1990s, when the ocean carbon sink did not grow as expected. Previous explanations of this behavior have focused on variability internal to the ocean or associated with coupled atmosphere/ocean modes. Here, we use an idealized upper ocean box model to illustrate that two external forcings are sufficient to explain... |
Tipo: Text |
Palavras-chave: Carbon cycle; Ocean carbon sink; Forced; Internal. |
Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00676/78775/80950.pdf |
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Lovenduski, Nicole S.; Fay, Amanda R.; Mckinley, Galen A.. |
We use output from a hindcast simulation (1958-2007) of an ocean biogeochemical and ecological model to inform an observational strategy for detection of a weakening Southern Ocean CO2 sink from surface ocean pCO(2) data. Particular emphasis is placed on resolving disparate conclusions about the Southern Ocean CO2 sink that have been drawn from surface ocean pCO(2) observation studies in the past. We find that long-term trends in Delta pCO(2)(pCO(2)(oc) - pCO(2)(atm)) can be used as a proxy for changes in the strength of the CO2 sink but must be interpreted with caution, as they are calculated from small differences in the oceanic and atmospheric pCO(2) trends. Large interannual, decadal, and multidecadal variability in Delta pCO(2) persists throughout the... |
Tipo: Text |
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Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00383/49430/49842.pdf |
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Fay, Amanda R.; Lovenduski, Nicole S.; Mckinley, Galen A.; Munro, David R.; Sweeney, Colm; Gray, Alison R.; Landschuetzer, Peter; Stephens, Britton B.; Takahashi, Taro; Williams, Nancy. |
The Southern Ocean is highly under-sampled for the purpose of assessing total carbon uptake and its variability. Since this region dominates the mean global ocean sink for anthropogenic carbon, understanding temporal change is critical. Underway measurements of pCO(2) collected as part of the Drake Passage Time-series (DPT) program that began in 2002 inform our understanding of seasonally changing air-sea gradients in pCO(2), and by inference the carbon flux in this region. Here, we utilize available pCO(2) observations to evaluate how the seasonal cycle, interannual variability, and long-term trends in surface ocean pCO(2) in the Drake Passage region compare to that of the broader subpolar Southern Ocean. Our results indicate that the Drake Passage is... |
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Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00673/78488/80826.pdf |
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