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| Titel |
Flexible C : N ratio enhances metabolism of large phytoplankton when resource supply is intermittent |
| VerfasserIn |
D. Talmy, J. Blackford, N. J. Hardman-Mountford, L. Polimene, M. J. Follows, R. J. Geider |
| 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. 17 ; Nr. 11, no. 17 (2014-09-12), S.4881-4895 |
| Datensatznummer |
250117591
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| Publikation (Nr.) |
 copernicus.org/bg-11-4881-2014.pdf |
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| Zusammenfassung |
| Phytoplankton cell size influences particle sinking rate, food web
interactions and biogeographical distributions. We present a model
in which the uptake, storage and assimilation of nitrogen and carbon
are explicitly resolved in different-sized phytoplankton cells. In
the model, metabolism and cellular C : N ratio are influenced by
the accumulation of carbon polymers such as carbohydrate and lipid,
which is greatest when cells are nutrient starved, or exposed to
high light. Allometric relations and empirical data sets are used to
constrain the range of possible C : N, and indicate that larger cells
can accumulate significantly more carbon storage compounds than
smaller cells. When forced with extended periods of darkness
combined with brief exposure to saturating irradiance, the model
predicts organisms large enough to accumulate significant carbon
reserves may on average synthesize protein and other functional
apparatus up to five times faster than smaller organisms. The
advantage of storage in terms of average daily protein synthesis
rate is greatest when modeled organisms were previously nutrient
starved, and carbon storage reservoirs saturated. Small organisms
may therefore be at a disadvantage in terms of average daily growth
rate in environments that involve prolonged periods of darkness and
intermittent nutrient limitation. We suggest this mechanism is
a significant constraint on phytoplankton C : N variability and
cell size distribution in different oceanic regimes. |
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