Growth of<i> Heterostegina depressa</i> under natural and laboratory conditions

Autor(en)
Wolfgang Eder, Antonino Briguglio, Johann Hohenegger
Abstrakt

The use of micro-computed tomography (μCT) provides a unique opportunity to look inside the shells of larger benthic foraminifera to investigate their structure by measuring linear and volumetric parameters. For this study, gamonts/schizonts and agamonts of the species Heterostegina depressa d'Orbigny were examined by μCT; each single chamber's volume was digitally measured. This approach enables cell growth to be recognised in terms of chamber volume sequence, which progressively increases until reproduction occurs. This sequence represents the ontogeny of the foraminiferal cell and has been used here to investigate controlling factors potentially affecting the process of chamber formation. This is manifested as instantaneous or periodic deviations of the realised chamber volumes derived from modelled growth functions. The results obtained on naturally grown specimens show oscillations in chamber volumes which can be modelled by sums of sinusoidal functions. A set of functions with similar periods in all investigated specimens points to lunar and tidal cycles.To determine whether such cyclic signals are genuine and not the effects of a theoretical model, the same analysis was conducted on specimens held in a closed laboratory facility, as they should not be affected by natural environmental effects. Surprisingly, similar cyclicities were observed in such samples. However, a solely genetic origin of these cycles couldn't be verified either. Therefore, detailed analysis on the phase equality of these growth oscillations have been done. This approach is pivotal for proving that the oscillatory patterns discovered in LBF are indeed genuine signals, and on how chamber growth might be influenced by tidal currents or lunar months.

Organisation(en)
Institut für Paläontologie
Externe Organisation(en)
Universiti Brunei Darussalam (UBD)
Journal
Marine Micropaleontology
Band
122
Seiten
27-43
Anzahl der Seiten
17
ISSN
0377-8398
DOI
https://doi.org/10.1016/j.marmicro.2015.11.005
Publikationsdatum
01-2016
Peer-reviewed
Ja
ÖFOS 2012
105118 Paläontologie
Schlagwörter
ASJC Scopus Sachgebiete
Oceanography, Palaeontology
Link zum Portal
https://ucris.univie.ac.at/portal/de/publications/growth-of-heterostegina-depressa-under-natural-and-laboratory-conditions(68b96ac6-097f-48da-b1e9-608e04eedf32).html