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| Titel |
Seasonal variations in concentration and lability of dissolved organic carbon in Tokyo Bay |
| VerfasserIn |
A. Kubo, M. Yamamoto-Kawai, J. Kanda |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 12, no. 1 ; Nr. 12, no. 1 (2015-01-15), S.269-279 |
| Datensatznummer |
250117771
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| Publikation (Nr.) |
 copernicus.org/bg-12-269-2015.pdf |
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| Zusammenfassung |
| Concentrations of recalcitrant and bioavailable dissolved organic carbon
(DOC) and their seasonal variations were investigated at three stations in
Tokyo Bay, Japan, and in two freshwater sources flowing into the bay. On
average, recalcitrant DOC (RDOC), as a remnant of DOC after 150 days of
bottle incubation, accounted for 78% of the total DOC in Shibaura sewage
treatment plant (STP) effluent, 67% in the upper Arakawa River water,
66% in the lower Arakawa River water, and 78% in surface bay water.
Bioavailable DOC (BDOC) concentrations, defined as DOC minus RDOC, were lower
than RDOC at all stations. In freshwater environments, RDOC concentrations
were almost constant throughout the year. In the bay, RDOC was higher during
spring and summer than in autumn and winter because of freshwater input and
biological production. The relative concentration of RDOC in the bay derived
from phytoplankton, terrestrial, and open-oceanic waters was estimated to be
8–10, 21–32, and 59–69%, respectively, based on multiple regression
analysis of RDOC, salinity, and chl a. In addition, comparison with
previous data from 1972 revealed that concentrations of RDOC and BDOC have
decreased by 33 and 74% at freshwater sites and 39 and 76% in Tokyo
Bay, while the ratio of RDOC to DOC has increased. The change in DOC
concentration and composition was probably due to increased amounts of STP
effluent entering the system. Tokyo Bay exported mostly RDOC to the open
ocean because of the remineralization of BDOC. |
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