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| Titel |
Long-term trends in ocean plankton production and particle export between 1960–2006 |
| VerfasserIn |
C. Laufkötter, M. Vogt, N. Gruber |
| 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 ; 10, no. 11 ; Nr. 10, no. 11 (2013-11-18), S.7373-7393 |
| Datensatznummer |
250085421
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| Publikation (Nr.) |
 copernicus.org/bg-10-7373-2013.pdf |
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| Zusammenfassung |
| We analyse long-term trends in marine primary and particle export production
and their link to marine phytoplankton community composition for the period
1960–2006 using a hindcast simulation of the Biogeochemical Elemental
Cycling Model coupled to the ocean component of the Community Climate System
Model. In our simulation, global primary and export production decrease
significantly over the last 50 yr, by 6.5% and 8% respectively. These
changes are associated with an 8.5% decrease in small phytoplankton
biomass and 5% decrease in zooplankton biomass. Diatom biomass decreases
globally by 3%, but with strong temporal and spatial variability.
The strongest decreases in primary and export production occur in the western
Pacific, where enhanced stratification leads to stronger nutrient limitation
and a decrease in total phytoplankton. The concurrent decrease in diatom
fraction and in zooplankton biomass causes a lower export efficiency in this
region. Substantial phytoplankton composition changes also occur in the
Southern Ocean and North Atlantic, although these are masked in part by a
high degree of interannual variability. In these regions, stronger wind
stress enhances mixing, reducing the biomass of small phytoplankton, while
diatoms profit from higher nutrient inputs and lower grazing pressure. The
relative fraction of diatoms correlates positively with the export efficiency
(r = 0.8, p < 0.05) in most areas except for the North Pacific and
Antarctic Circumpolar Current, where the correlation is negative (r = –0.5,
p < 0.05). However, the long-term trends in global export efficiency are
ultimately driven by the reduction in small phytoplankton and particularly
decreases in coccolithophore biomass. The diagnosed trends point toward a
substantial sensitivity of marine primary production and export to climatic
variations and trends. |
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