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| Titel |
Peruvian upwelling plankton respiration: calculations of carbon flux, nutrient retention efficiency, and heterotrophic energy production |
| VerfasserIn |
T. T. Packard, N. Osma, I. Fernández-Urruzola, L. A. Codispoti, J. P. Christensen, M. Gomez |
| 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 ; 12, no. 9 ; Nr. 12, no. 9 (2015-05-06), S.2641-2654 |
| Datensatznummer |
250117924
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| Publikation (Nr.) |
 copernicus.org/bg-12-2641-2015.pdf |
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| Zusammenfassung |
| Oceanic depth profiles of plankton respiration are described by a power
function, RCO2 = (RCO2)0 (z/z0)b, similar
to the vertical carbon flux profile. Furthermore, because both ocean
processes are closely related, conceptually and mathematically, each can be
calculated from the other. The exponent b, always negative, defines the
maximum curvature of the respiration–depth profile and controls the carbon
flux. When |b| is large, the carbon flux (FC) from the
epipelagic ocean is low and the nutrient retention efficiency (NRE) is high,
allowing these waters to maintain high productivity. The opposite occurs when
|b| is small. This means that the attenuation of respiration in ocean water
columns is critical in understanding and predicting both vertical
FC as well as the capacity of epipelagic ecosystems to retain
their nutrients. The ratio of seawater RCO2 to incoming
FC is the NRE, a new metric that represents nutrient regeneration
in a seawater layer in reference to the nutrients introduced into that layer
via FC. A depth profile of FC is the integral of
water column respiration. This relationship facilitates calculating ocean
sections of FC from water column respiration. In an FC
section and in a NRE section across the Peruvian upwelling system we found an
FC maximum and a NRE minimum extending down to 400 m, 50 km off the
Peruvian coast over the upper part of the continental slope. Finally,
considering the coupling between respiratory electron transport system
activity and heterotrophic oxidative phosphorylation promoted the calculation
of an ocean section of heterotrophic energy production (HEP). It ranged from
250 to 500 J d−1 m−3 in the euphotic zone to less than
5 J d−1 m−3 below 200 m on this ocean section. |
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