Long-term trend of CO<sub>2</sub> and ocean acidification in the surface water of the Ulleung Basin, the East/Japan Sea inferred from the underway observational data
Anthropogenic carbon is responsible for both global warming and ocean acidification. Efforts are underway to understand the role of ocean in a high CO<sub>2</sub> world on a global context. However, marginal seas received little attention despite their significant contribution to biogeoc...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2014-05-01
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| Series: | Biogeosciences |
| Online Access: | http://www.biogeosciences.net/11/2443/2014/bg-11-2443-2014.pdf |
| Summary: | Anthropogenic carbon is responsible for both global warming and ocean
acidification. Efforts are underway to understand the role of ocean in a high
CO<sub>2</sub> world on a global context. However, marginal seas received little
attention despite their significant contribution to biogeochemical cycles.
Here we report the CO<sub>2</sub> increase and ocean acidification in the surface
waters of the Ulleung Basin (UB) of the East/Japan Sea, and possible causes
are discussed. Fourteen observations of surface <i>f</i>CO<sub>2</sub> were made in the
period from 1995 to 2009. The contribution of temperature variation to the
seasonality of <i>f</i>CO<sub>2</sub> was almost equivalent to the non-thermal effect in
the UB. However, the difference of relative contribution with the season
makes two seasonal peaks of <i>f</i>CO<sub>2</sub> in the surface water of the UB.
Non-thermal effect contributed to the surface <i>f</i>CO<sub>2</sub> drawdown in summer,
whereas the surface <i>f</i>CO<sub>2</sub> elevation in winter. The decadal trend of
<i>f</i>CO<sub>2</sub> increment was estimated by harmonic analysis. The estimated rates
of increase of <i>f</i>CO<sub>2</sub> were 1.8 ± 0.4 μatm yr<sup>−1</sup> for
the atmosphere and 2.7 ± 1.1 μatm yr<sup>−1</sup> for the surface
water. The ocean acidification trend, calculated from total alkalinity and
<i>f</i>CO<sub>2</sub>, was estimated to be −0.03 ± 0.02 pH units decade<sup>−1</sup>.
These rates seem to be higher than observations at most other ocean
time-series sites during the same period of time. Sustained observations are
required to understand more accurate trend in this area. |
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| ISSN: | 1726-4170 1726-4189 |