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| Titel |
Regional and temporal variability of sinking organic matter in the subtropical northeast Atlantic Ocean: a biomarker diagnosis |
| VerfasserIn |
I. J. Alonso-González, J. Arístegui, C. Lee, A. Calafat |
| 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. 7 ; Nr. 7, no. 7 (2010-07-06), S.2101-2115 |
| Datensatznummer |
250004891
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| Publikation (Nr.) |
 copernicus.org/bg-7-2101-2010.pdf |
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| Zusammenfassung |
| Sinking particles through the pelagic ocean have been traditionally
considered the most important vehicle by which the biological pump
sequesters carbon in the ocean interior. Nevertheless, regional scale
variability in particle flux is a major outstanding issue in oceanography.
Here, we have studied the regional and temporal variability of total
particulate organic matter fluxes, as well as chloropigment and total
hydrolyzed amino acid (THAA) compositions and fluxes in the Canary Current
region, between 20–30° N, during two contrasting periods: August 2006,
characterized by warm and stratified waters, but also intense winds which
enhanced eddy development south of the Canary Islands, and February 2007,
characterized by colder waters, less stratification and higher productivity.
We found that the eddy-field generated south of the Canary Islands enhanced
by >2 times particulate organic carbon (POC) export with respect to
stations (FF; far-field) outside the eddy-field influence. We also observed
flux increases of one order of magnitude in chloropigment and 2 times in
THAA in the eddy-field relative to FF stations. Principal Components
Analysis (PCA) was performed to assess changes in particulate organic matter
composition between stations. At eddy-field stations, higher chlorophyll
enrichment reflected "fresher" material, while at FF stations a higher
proportion of pheophytin indicated greater degradation due to microbes and
microzooplankton. PCA also suggests that phytoplankton community structure,
particularly the dominance of diatoms versus carbonate-rich plankton, is the
major factor influencing the POC export within the eddy field. In February,
POC export fluxes were the highest ever reported for this area, reaching
values of ~15 mmol C m−2 d−1 at 200 m depth. Compositional
changes in pigments and THAA indicate that the source of sinking particles
varies zonally and meridionally and suggest that sinking particles were more
degraded at near-coastal stations relative to open ocean stations. |
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