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| Titel |
Ballast minerals and the sinking carbon flux in the ocean: carbon-specific respiration rates and sinking velocity of marine snow aggregates |
| VerfasserIn |
M. H. Iversen, H. Ploug |
| 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 ; 7, no. 9 ; Nr. 7, no. 9 (2010-09-07), S.2613-2624 |
| Datensatznummer |
250004961
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| Publikation (Nr.) |
 copernicus.org/bg-7-2613-2010.pdf |
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| Zusammenfassung |
| Recent observations have shown that fluxes of ballast minerals (calcium
carbonate, opal, and lithogenic material) and organic carbon fluxes are
closely correlated in the bathypelagic zones of the ocean. Hence it has been
hypothesized that incorporation of biogenic minerals within marine
aggregates could either protect the organic matter from decomposition and/or
increase the sinking velocity via ballasting of the aggregates. Here we
present the first combined data on size, sinking velocity, carbon-specific
respiration rate, and composition measured directly in three aggregate
types; Emiliania huxleyi aggregates (carbonate ballasted), Skeletonema costatum aggregates (opal ballasted), and
aggregates made from a mix of both E. huxleyi and S. costatum (carbonate and opal ballasted).
Overall average carbon-specific respiration rate was ~0.13 d−1
and did not vary with aggregate type and size. Ballasting from carbonate
resulted in 2- to 2.5-fold higher sinking velocities than those of aggregates
ballasted by opal. We compiled literature data on carbon-specific
respiration rate and sinking velocity measured in aggregates of different
composition and sources. Compiled carbon-specific respiration rates
(including this study) vary between 0.08 d−1 and 0.20 d−1. Sinking
velocity increases with increasing aggregate size within homogeneous sources
of aggregates. When compared across different particle and aggregate
sources, however, sinking velocity appeared to be independent of particle or
aggregate size. The carbon-specific respiration rate per meter settled varied between
0.0002 m−1 and 0.0030 m−1, and decreased with increasing aggregate size.
It was lower for calcite ballasted aggregates as compared to that of similar sized opal ballasted aggregates. |
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