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| Titel |
Growth, chamber building rate and reproduction time of Palaeonummulites venosus under natural conditions. |
| VerfasserIn |
Shunichi Kinoshita, Wolfgang Eder, Julia Wöger, Johann Hohenegger, Antonino Briguglio |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250146553
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| Publikation (Nr.) |
 EGU/EGU2017-10581.pdf |
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| Zusammenfassung |
| Investigations on Palaeonummulites venosus using the natural laboratory approach for
determining chamber building rate, test diameter increase rate, reproduction time and
longevity is based on the decomposition of monthly obtained frequency distributions based
on chamber number and test diameter into normal-distributed components. The shift of the
component parameters ‘mean’ and ‘standard deviation’ during the investigation
period of 15 months was used to calculate Michaelis-Menten functions applied to
estimate the averaged chamber building rate and diameter increase rate under natural
conditions.
The individual dates of birth were estimated using the inverse averaged chamber building
rate and the inverse diameter increase rate fitted by the individual chamber number or the
individual test diameter at the sampling date. Distributions of frequencies and densities (i.e.
frequency divided by sediment weight) based on chamber building rate and diameter increase
rate resulted both in a continuous reproduction through the year with two peaks, the stronger
in May /June determined as the beginning of the summer generation (generation1) and the
weaker in November determined as the beginning of the winter generation (generation 2).
This reproduction scheme explains the existence of small and large specimens in the same
sample.
Longevity, calculated as the maximum difference in days between the individual’s
birth date and the sampling date seems to be round about one year, obtained by
both estimations based on the chamber building rate and the diameter increase rate. |
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