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Titel |
An experimental study on the effects of nutrient enrichment on organic carbon persistence in the western Pacific oligotrophic gyre |
VerfasserIn |
J. Liu, N. Jiao, K. Tang |
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 ; 11, no. 18 ; Nr. 11, no. 18 (2014-09-23), S.5115-5122 |
Datensatznummer |
250117606
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Publikation (Nr.) |
copernicus.org/bg-11-5115-2014.pdf |
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Zusammenfassung |
Carbon sequestration in the ocean is of great concern with respect to the
mitigation of global warming. How to hold the fixed organic carbon in the
presence of tremendous numbers of heterotrophic microorganisms in marine
environments is the central issue. We previously hypothesized that excessive
nutrients would ultimately decrease the storage of organic carbon in marine
environments. To test this, a series of in situ nutrient enrichment
incubation experiments were conducted at a site (17.59° N,
127.00° E) within the western Pacific oligotrophic gyre. Five
treatments were employed: glucose (Glu), algal exudation organic material
(EOM), nitrate (N) and phosphate (P), N and P in combination with glucose and
a control with no added nutrients. The results showed that the dissolved
organic carbon consumption rates and bacterial community specific growth
rates were enhanced by inorganic nutrient enrichment treatments during the
initial 48 h incubation. At the end of 14 days of incubation, about
one-third (average 3.3 μmol C kg−1) more organic carbon was respired
in the glucose-enriched incubation with the addition of inorganic nutrients
compared to that without. In contrast, when nutrients were limiting, glucose
could not be efficiently used by the bacteria and thus it remained in the
environment. These results suggest that repletion of inorganic nutrients
could facilitate microbial consumption of organic carbon and thus has a
significant impact on carbon cycling in the environment. |
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