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Extraordinary slow degradation of dissolved organic carbon (DOC) in a cold marginal sea.

Kim TH, Kim G, Lee SA, Dittmar T - Sci Rep (2015)

Bottom Line: In general, DOC introduced into the deep ocean undergoes a significant degradation over a centennial time scale (i.e., ~50 μM to ~34 μM in the North Atlantic and Mediterranean Sea).The degradation rate in this sea is estimated to be 0.04 μmol C kg(-1) yr(-1), which is 2-3 times lower than that in the North Atlantic and Mediterranean Sea.Since the source of DOC in the deep EJS is found to be of marine origin on the basis of δ(13)C-DOC signatures, this slow degradation rate seems to be due to low temperature (<1 °C) in the entire deep water column.

View Article: PubMed Central - PubMed

Affiliation: School of Earth and Environmental Sciences/RIO, Seoul National University, Seoul, 151-747, Republic of Korea.

ABSTRACT
Dissolved organic carbon (DOC) is the largest organic carbon reservoir in the ocean, and the amount of carbon in this reservoir rivals that in atmospheric CO2. In general, DOC introduced into the deep ocean undergoes a significant degradation over a centennial time scale (i.e., ~50 μM to ~34 μM in the North Atlantic and Mediterranean Sea). However, we here show that high concentrations of DOC (58 ± 4 μM) are maintained almost constantly over 100 years in the entire deep East/Japan Sea (EJS). The degradation rate in this sea is estimated to be 0.04 μmol C kg(-1) yr(-1), which is 2-3 times lower than that in the North Atlantic and Mediterranean Sea. Since the source of DOC in the deep EJS is found to be of marine origin on the basis of δ(13)C-DOC signatures, this slow degradation rate seems to be due to low temperature (<1 °C) in the entire deep water column. This observational result suggests that the storage capacity of DOC in the world ocean is very sensitive to global warming and slowdown of global deep-water overturning.

No MeSH data available.


Transectional contours of dissolved organic carbon (DOC) and apparent oxygen utilization (AOU) in the East/Japan Sea.Distributions of DOC and AOU in the East/Japan Sea during May 8 to 22, 2007 and May 28 to June 2, 2007. Red lines indicate distributions of DOC reported by Kim and Kim (ref. 23).
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f3: Transectional contours of dissolved organic carbon (DOC) and apparent oxygen utilization (AOU) in the East/Japan Sea.Distributions of DOC and AOU in the East/Japan Sea during May 8 to 22, 2007 and May 28 to June 2, 2007. Red lines indicate distributions of DOC reported by Kim and Kim (ref. 23).

Mentions: The concentrations of DOC in the deep layer of the EJS in May 2007 decreased slightly from the north (59 ± 3 μM) to the south (55 ± 2 μM) along the deep-sea current flows, which was associated with biological degradation reflected in apparent oxygen utilization (AOU) (Fig. 3). Considering the fact that these DOC profiles include the entire East Sea through several cruises, including the southwestern EJS stations23, over the last 10 years, the DOC concentrations in the deep EJS were remarkably stable, and neither systematic nor significant differences were observed among the stations.


Extraordinary slow degradation of dissolved organic carbon (DOC) in a cold marginal sea.

Kim TH, Kim G, Lee SA, Dittmar T - Sci Rep (2015)

Transectional contours of dissolved organic carbon (DOC) and apparent oxygen utilization (AOU) in the East/Japan Sea.Distributions of DOC and AOU in the East/Japan Sea during May 8 to 22, 2007 and May 28 to June 2, 2007. Red lines indicate distributions of DOC reported by Kim and Kim (ref. 23).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4561884&req=5

f3: Transectional contours of dissolved organic carbon (DOC) and apparent oxygen utilization (AOU) in the East/Japan Sea.Distributions of DOC and AOU in the East/Japan Sea during May 8 to 22, 2007 and May 28 to June 2, 2007. Red lines indicate distributions of DOC reported by Kim and Kim (ref. 23).
Mentions: The concentrations of DOC in the deep layer of the EJS in May 2007 decreased slightly from the north (59 ± 3 μM) to the south (55 ± 2 μM) along the deep-sea current flows, which was associated with biological degradation reflected in apparent oxygen utilization (AOU) (Fig. 3). Considering the fact that these DOC profiles include the entire East Sea through several cruises, including the southwestern EJS stations23, over the last 10 years, the DOC concentrations in the deep EJS were remarkably stable, and neither systematic nor significant differences were observed among the stations.

Bottom Line: In general, DOC introduced into the deep ocean undergoes a significant degradation over a centennial time scale (i.e., ~50 μM to ~34 μM in the North Atlantic and Mediterranean Sea).The degradation rate in this sea is estimated to be 0.04 μmol C kg(-1) yr(-1), which is 2-3 times lower than that in the North Atlantic and Mediterranean Sea.Since the source of DOC in the deep EJS is found to be of marine origin on the basis of δ(13)C-DOC signatures, this slow degradation rate seems to be due to low temperature (<1 °C) in the entire deep water column.

View Article: PubMed Central - PubMed

Affiliation: School of Earth and Environmental Sciences/RIO, Seoul National University, Seoul, 151-747, Republic of Korea.

ABSTRACT
Dissolved organic carbon (DOC) is the largest organic carbon reservoir in the ocean, and the amount of carbon in this reservoir rivals that in atmospheric CO2. In general, DOC introduced into the deep ocean undergoes a significant degradation over a centennial time scale (i.e., ~50 μM to ~34 μM in the North Atlantic and Mediterranean Sea). However, we here show that high concentrations of DOC (58 ± 4 μM) are maintained almost constantly over 100 years in the entire deep East/Japan Sea (EJS). The degradation rate in this sea is estimated to be 0.04 μmol C kg(-1) yr(-1), which is 2-3 times lower than that in the North Atlantic and Mediterranean Sea. Since the source of DOC in the deep EJS is found to be of marine origin on the basis of δ(13)C-DOC signatures, this slow degradation rate seems to be due to low temperature (<1 °C) in the entire deep water column. This observational result suggests that the storage capacity of DOC in the world ocean is very sensitive to global warming and slowdown of global deep-water overturning.

No MeSH data available.