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| Titel |
Seasonal dynamics of Pseudocalanus minutus elongatus and Acartia spp. in the southern Baltic Sea (Gdańsk Deep) – numerical simulations |
| VerfasserIn |
L. Dzierzbicka-Glowacka, L. Bielecka, S. Mudrak |
| 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 ; 3, no. 4 ; Nr. 3, no. 4 (2006-12-18), S.635-650 |
| Datensatznummer |
250001170
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| Publikation (Nr.) |
 copernicus.org/bg-3-635-2006.pdf |
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| Zusammenfassung |
A population dynamics model for copepods is presented, describing the seasonal
dynamics of Pseudocalanus minutus elongatus and Acartia spp. in the
southern Baltic Sea (Gdańsk Deep). The copepod model was coupled with
a one-dimensional physical and biological upper layer model for
nutrients (total inorganic nitrogen, phosphate), phytoplankton,
microzooplankton, and an early juvenile of herring as a predator.
In this model, mesozooplankton (herbivorous copepods)
has been introduced as an animal having definite patterns of growth in
successive stages, reproduction and mortality. The populations are
represented by 6 cohorts in different developmental stages, thus assuming
that recruitment of the next generation occurs after a fixed period of
adult life. The copepod model links trophic processes and population
dynamics, and simulates individual growth within cohorts and the changes
in biomass between cohorts.
The simulations of annual cycles of copepods contain one complete generation
of Pseudocalanus and two generations
of Acartia in the whole column water, and
indicate the importance of growth in the older stages of 6 cohorts of each species,
to arrive at a total population biomass. The peaks of copepods' biomass
are larger at the turn of June and July for Pseudocalanus and smaller in July for
Acartia, lagging that of phytoplankton by ca. two mouths, due to the growth of
cohorts in successive stages and egg production by females.
The numerical results show that the investigated species could not be the
main factor limiting the spring phytoplankton bloom in the Gdańsk Deep,
because the initial development was slow for Acartia and
faster for Pseudocalanus, but the main development formed after the bloom,
in both cases. The phytoplankton bloom is very important in the diet of the adults
of the copepods, but it is not particularly important for the youngest part of new generation
(early nauplii). However, the simulated microzooplankton biomass was enough
high to conclude, in our opinion, that, in this case, it was a major cause
in limiting phytoplankton bloom. The model presented here is a next step in understanding how the population
dynamics of a dominant species in the southern Baltic Sea interact with
the environment. |
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