Growth estimation of the larger foraminifer Heterostegina depressa by means of population dynamics

Author(s)
Wolfgang Eder, Julia Wöger, Shunichi Kinoshita, Johann Hohenegger, Antonino Briguglio
Abstract

In Heterostegina depressa, the flagship species of laboratory investigations of larger benthic foraminifera (LBF) since the 70’s, the timing of reproduction, longevity and natural chamber building rates are still understudied. A recently developed method, the natural laboratory (sensu Hohenegger), has been applied on H. depressa populations from Sesoko Jima, NW Okinawa, Japan. An averaged chamber building rate and longevity of H. depressa were calculated based on 17 monthly samplings at fixed stations. All samples were collected at 20 and 50 m water depths using SCUBA. Live populations were dried and investigated by microCT. The monthly frequency distributions of chamber numbers and test diameters have been decomposed in normally distributed components. For each month, mean and standard deviations of the components were used to calculate the maximum chamber number and maximum test diameter. Based on these values, the natural chamber building rate (CBR) or diameter increase rate (DIR) could be estimated using the Michaelis-Menten function. CBR and DIR were inverted to estimate the ‘birthdate’ of all investigated individuals. Based on frequencies of these ‘birthdates’, main reproduction events could be detected and compared to the reproduction timing of other subtropical and tropical LBF taxa. Furthermore, peaks in reproduction could be linked to monsoon wet seasons (=“rainy seasons”) and winter rains.

Organisation(s)
Department of Palaeontology
External organisation(s)
Università degli Studi di Genova
Journal
PeerJ
Volume
6
No. of pages
34
ISSN
2167-8359
DOI
https://doi.org/10.7717/peerj.6096
Publication date
01-2019
Peer reviewed
Yes
Austrian Fields of Science 2012
105118 Palaeontology
Keywords
ASJC Scopus subject areas
General Agricultural and Biological Sciences, General Biochemistry,Genetics and Molecular Biology, General Neuroscience
Portal url
https://ucrisportal.univie.ac.at/en/publications/d4e6164d-91b3-42f8-896d-806cfd05ca9c