scholarly journals Factors Regulating Nitrification in the Arctic Ocean: Potential Impact of Sea Ice Reduction and Ocean Acidification

2019 ◽  
Vol 33 (8) ◽  
pp. 1085-1099 ◽  
Author(s):  
Takuhei Shiozaki ◽  
Minoru Ijichi ◽  
Amane Fujiwara ◽  
Akiko Makabe ◽  
Shigeto Nishino ◽  
...  
Keyword(s):  
Sea Ice ◽  
Ocean Acidification ◽  
Arctic Ocean ◽  
The Arctic ◽  
The Arctic Ocean ◽  
Potential Impact ◽  
Sea Ice Reduction

scholarly journals Impact of rapid sea-ice reduction in the Arctic Ocean on the rate of ocean acidification

2012 ◽  
Vol 9 (6) ◽  
pp. 2365-2375 ◽  
Author(s):  
A. Yamamoto ◽  
M. Kawamiya ◽  
A. Ishida ◽  
Y. Yamanaka ◽  
S. Watanabe
Keyword(s):  
Sea Ice ◽  
Arctic Ocean ◽  
Reduction Rate ◽  
Co2 Concentration ◽  
The Arctic ◽  
Saturation State ◽  
Aragonite Saturation ◽  
The Arctic Ocean ◽  
Arctic Surface ◽  
Sea Ice Reduction

Abstract. The largest pH decline and widespread undersaturation with respect to aragonite in this century due to uptake of anthropogenic carbon dioxide in the Arctic Ocean have been projected. The reductions in pH and aragonite saturation state in the Arctic Ocean have been caused by the melting of sea ice as well as by an increase in the concentration of atmospheric carbon dioxide. Therefore, future projections of pH and aragonite saturation in the Arctic Ocean will be affected by how rapidly the reduction in sea ice occurs. The observed recent Arctic sea-ice loss has been more rapid than projected by many of the climate models that contributed to the Intergovernmental Panel on Climate Change Fourth Assessment Report. In this study, the impact of sea-ice reduction rate on projected pH and aragonite saturation state in the Arctic surface waters was investigated. Reductions in pH and aragonite saturation were calculated from the outputs of two versions of an Earth system model with different sea-ice reduction rates under similar CO2 emission scenarios. The newer model version projects that Arctic summer ice-free condition will be achieved by the year 2040, and the older version predicts ice-free condition by 2090. The Arctic surface water was projected to be undersaturated with respect to aragonite in the annual mean when atmospheric CO2 concentration reaches 513 (606) ppm in year 2046 (2056) in new (old) version. At an atmospheric CO2 concentration of 520 ppm, the maximum differences in pH and aragonite saturation state between the two versions were 0.1 and 0.21 respectively. The analysis showed that the decreases in pH and aragonite saturation state due to rapid sea-ice reduction were caused by increases in both CO2 uptake and freshwater input. Thus, the reductions in pH and aragonite saturation state in the Arctic surface waters are significantly affected by the difference in future projections for sea-ice reduction rate. Our results suggest that the future reductions in pH and aragonite saturation state could be significantly faster than previously projected if the sea-ice reduction in the Arctic Ocean keeps its present pace.

scholarly journals Impact of rapid sea-ice reduction in the Arctic Ocean on the rate of ocean acidification

2011 ◽  
Vol 8 (5) ◽  
pp. 10617-10644
Author(s):  
A. Yamamoto ◽  
M. Kawamiya ◽  
A. Ishida ◽  
Y. Yamanaka ◽  
S. Watanabe
Keyword(s):  
Sea Ice ◽  
Arctic Ocean ◽  
Surface Waters ◽  
Co2 Concentration ◽  
The Arctic ◽  
Saturation State ◽  
Aragonite Saturation ◽  
The Arctic Ocean ◽  
Arctic Surface ◽  
Sea Ice Reduction

Abstract. The largest pH decline and widespread undersaturation with respect to aragonite in this century due to uptake of anthropogenic carbon dioxide in the Arctic Ocean have been projected. The reductions in pH and aragonite saturation state have been caused primarily by an increase in the concentration of atmospheric carbon dioxide. However, in a previous study, simulations with and without warming showed that these reductions in the Arctic Ocean also advances due to the melting of sea ice caused by global warming. Therefore, future projections of pH and aragonite saturation in the Arctic Ocean will be affected by how rapidly the reduction in sea ice occurs. In this study, the impact of sea-ice reduction rate on projected pH and aragonite saturation state in the Arctic surface waters was investigated. Reductions in pH and aragonite saturation were calculated from the outputs of two versions of an earth system model (ESM) with different sea-ice reduction rates under similar CO2 emission scenarios. The newer model version projects that Arctic summer ice-free condition will be achieved by the year 2040, and the older version predicts ice-free condition by 2090. The Arctic surface water was projected to be undersaturated with respect to aragonite in the annual mean when atmospheric CO2 concentration reached 480 (550) ppm in year 2040 (2048) in new (old) version. At an atmospheric CO2 concentration of 520 ppm, the maximum differences in pH and aragonite saturation state between the two versions were 0.08 and 0.15, respectively. The analysis showed that the decreases in pH and aragonite saturation state due to rapid sea-ice reduction were caused by increases in both CO2 uptake and freshwater input. Thus, the reductions in pH and aragonite saturation state in the Arctic surface waters are significantly affected by the difference in future projections for sea-ice reduction rate. The critical CO2 concentration, at which the Arctic surface waters become undersaturated with respect to aragonite on annual mean bias, would be lower by 70 ppm in the version with the rapid sea-ice reduction.

Low frequency sound absorption in the Arctic Ocean: Potential impact of ocean acidification

2014 ◽  
Vol 135 (4) ◽  
pp. 2306-2306 ◽  
Author(s):  
David Browning ◽  
Peter D. Herstein ◽  
Peter M. Scheifele ◽  
Raymond W. Hasse
Keyword(s):  
Ocean Acidification ◽  
Arctic Ocean ◽  
Sound Absorption ◽  
Low Frequency ◽  
The Arctic ◽  
Frequency Sound ◽  
The Arctic Ocean ◽  
Potential Impact

Enhancement/reduction of biological pump depends on ocean circulation in the sea-ice reduction regions of the Arctic Ocean

2011 ◽  
Vol 67 (3) ◽  
pp. 305-314 ◽  
Author(s):  
Shigeto Nishino ◽  
Takashi Kikuchi ◽  
Michiyo Yamamoto-Kawai ◽  
Yusuke Kawaguchi ◽  
Toru Hirawake ◽  
...  
Keyword(s):  
Sea Ice ◽  
Arctic Ocean ◽  
Ocean Circulation ◽  
The Arctic ◽  
Biological Pump ◽  
The Arctic Ocean ◽  
Sea Ice Reduction

scholarly journals The Arctic Ocean marine carbon cycle: evaluation of air-sea CO<sub>2</sub> exchanges, ocean acidification impacts and potential feedbacks

2009 ◽  
Vol 6 (4) ◽  
pp. 6695-6747 ◽  
Author(s):  
N. R. Bates ◽  
J. T. Mathis
Keyword(s):  
Gas Exchange ◽  
Carbon Cycle ◽  
Sea Ice ◽  
Ocean Acidification ◽  
Arctic Ocean ◽  
Surface Waters ◽  
The Arctic ◽  
Subsurface Water ◽  
Phytoplankton Primary Production ◽  
The Arctic Ocean

Abstract. At present, although seasonal sea-ice cover mitigates atmosphere-ocean gas exchange, the Arctic Ocean takes up carbon dioxide (CO2) on the order of −65 to −175 Tg C year−1, contributing 5–14% to the global balance of CO2 sinks and sources. Because of this, the Arctic Ocean is an important influence on the global carbon cycle, with the marine carbon cycle and atmosphere-ocean CO2 exchanges sensitive to Arctic Ocean and global climate change feedbacks. In the near-term, further sea-ice loss and increases in phytoplankton growth rates are expected to increase the uptake of CO2 by Arctic surface waters, although mitigated somewhat by surface warming in the Arctic. Thus, the capacity of the Arctic Ocean to uptake CO2 is expected to alter in response to environmental changes driven largely by climate. These changes are likely to continue to modify the physics, biogeochemistry, and ecology of the Arctic Ocean in ways that are not yet fully understood. In surface waters, sea-ice melt, river runoff, cooling and uptake of CO2 through air-sea gas exchange combine to decrease the calcium carbonate (CaCO3) mineral saturation states (Ω) of seawater that is counteracted by seasonal phytoplankton primary production (PP). Biological processes drive divergent trajectories for Ω in surface and subsurface waters of Arctic shelves with subsurface water experiencing undersaturation with respect to aragonite and calcite. Thus, in response to increased sea-ice loss, warming and enhanced phytoplankton PP, the benthic ecosystem of the Arctic shelves are expected to be negatively impacted by the biological amplification of ocean acidification. This in turn reduces the ability of many species to produce CaCO3 shells or tests with profound implications for Arctic marine ecosystems.

scholarly journals Anomalous sea-ice reduction in the Eurasian Basin of the Arctic Ocean during summer 2010

Polar Science ◽  
2012 ◽  
Vol 6 (1) ◽  
pp. 39-53 ◽  
Author(s):  
Yusuke Kawaguchi ◽  
Jennifer K. Hutchings ◽  
Takashi Kikuchi ◽  
James H. Morison ◽  
Richard A. Krishfield
Keyword(s):  
Sea Ice ◽  
Arctic Ocean ◽  
The Arctic ◽  
The Arctic Ocean ◽  
Eurasian Basin ◽  
Sea Ice Reduction

scholarly journals The Arctic Ocean marine carbon cycle: evaluation of air-sea CO<sub>2</sub> exchanges, ocean acidification impacts and potential feedbacks

2009 ◽  
Vol 6 (11) ◽  
pp. 2433-2459 ◽  
Author(s):  
N. R. Bates ◽  
J. T. Mathis
Keyword(s):  
Gas Exchange ◽  
Carbon Cycle ◽  
Sea Ice ◽  
Ocean Acidification ◽  
Arctic Ocean ◽  
Surface Waters ◽  
Environmental Changes ◽  
The Arctic ◽  
Phytoplankton Primary Production ◽  
The Arctic Ocean

Abstract. At present, although seasonal sea-ice cover mitigates atmosphere-ocean gas exchange, the Arctic Ocean takes up carbon dioxide (CO2) on the order of −66 to −199 Tg C year−1 (1012 g C), contributing 5–14% to the global balance of CO2 sinks and sources. Because of this, the Arctic Ocean has an important influence on the global carbon cycle, with the marine carbon cycle and atmosphere-ocean CO2 exchanges sensitive to Arctic Ocean and global climate change feedbacks. In the near-term, further sea-ice loss and increases in phytoplankton growth rates are expected to increase the uptake of CO2 by Arctic Ocean surface waters, although mitigated somewhat by surface warming in the Arctic. Thus, the capacity of the Arctic Ocean to uptake CO2 is expected to alter in response to environmental changes driven largely by climate. These changes are likely to continue to modify the physics, biogeochemistry, and ecology of the Arctic Ocean in ways that are not yet fully understood. In surface waters, sea-ice melt, river runoff, cooling and uptake of CO2 through air-sea gas exchange combine to decrease the calcium carbonate (CaCO3) mineral saturation states (Ω) of seawater while seasonal phytoplankton primary production (PP) mitigates this effect. Biological amplification of ocean acidification effects in subsurface waters, due to the remineralization of organic matter, is likely to reduce the ability of many species to produce CaCO3 shells or tests with profound implications for Arctic marine ecosystems

Aragonite Undersaturation in the Arctic Ocean: Effects of Ocean Acidification and Sea Ice Melt

Science ◽  
2009 ◽  
Vol 326 (5956) ◽  
pp. 1098-1100 ◽  
Author(s):  
M. Yamamoto-Kawai ◽  
F. A. McLaughlin ◽  
E. C. Carmack ◽  
S. Nishino ◽  
K. Shimada
Keyword(s):  
Sea Ice ◽  
Ocean Acidification ◽  
Arctic Ocean ◽  
The Arctic ◽  
Ice Melt ◽  
The Arctic Ocean
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