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| Titel |
Small-scale spatial structure in plankton distributions |
| VerfasserIn |
A. Tzella, P. H. Haynes |
| 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 ; 4, no. 2 ; Nr. 4, no. 2 (2007-03-02), S.173-179 |
| Datensatznummer |
250001616
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| Publikation (Nr.) |
 copernicus.org/bg-4-173-2007.pdf |
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| Zusammenfassung |
| The observed filamental nature of plankton populations suggests that stirring
plays an important role in determining their spatial structure. If diffusive
mixing is neglected, the various interacting biological species within a
fluid parcel are determined by the parcel time history. The induced spatial
structure has been shown to be a result of competition between the time
evolution of the biological processes involved and the stirring induced by
the flow as measured, for example, by the rate of divergence of the distance
of neighbouring fluid parcels. In the work presented here we examine a simple
biological model based on delay-differential equations, previously seen in
Abraham (1998), including nutrients, phytoplankton and zooplankton, coupled
to a strain flow. Previous theoretical investigations made on a differential
equation model (Hernández-Garcia et al., 2002) imply that the latter two should
share the same small-scale structure. The generalisation from differential
equations to delay-differential equations, associated with the addition of a
maturation time to the zooplankton growth, should not make a difference,
provided sufficiently small spatial scales are considered. However, this
theoretical prediction is in contradiction with the results of
Abraham (1998), where the phytoplankton and zooplankton structures remain
uncorrelated at all length scales. A new set of numerical experiments is
performed here which show that these two regimes coexist. On larger scales,
there is a decoupling of the spatial structure of the zooplankton
distribution on the one hand, and the phytoplankton and nutrient on the
other. On the other hand, at small enough length scales, the phytoplankton
and zooplankton share the same spatial structure as expected by the theory
involving no maturation time. |
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