The complex test structures of LBFs have attracted scientific interest for a long time. Environmental constraints, like hydrodynamic energy, light penetration and nutrient influx, influence test morphology ( Hohenegger, 2004 Briguglio & Hohenegger, 2009 Hohenegger, 2011). Therefore, they are restricted to the photic zone of warm-temperate to tropic carbonate environments ( Hallock, Röttger & Wetmore, 1991). The nummulitid foraminifer Heterostegina depressa belongs to the non-taxonomic (paraphyletic) group of larger benthic foraminifera (LBF), which are characterized by their symbiosis with phototrophic microalgae. Furthermore, peaks in reproduction could be linked to monsoon wet seasons (=“rainy seasons”) and winter rains. 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. CBR and DIR were inverted to estimate the ‘birthdate’ of all investigated individuals. Based on these values, the natural chamber building rate (CBR) or diameter increase rate (DIR) could be estimated using the Michaelis-Menten function. For each month, mean and standard deviations of the components were used to calculate the maximum chamber number and maximum test diameter. The monthly frequency distributions of chamber numbers and test diameters have been decomposed in normally distributed components. Live populations were dried and investigated by microCT. All samples were collected at 20 and 50 m water depths using SCUBA. depressa were calculated based on 17 monthly samplings at fixed stations. An averaged chamber building rate and longevity of H. depressa populations from Sesoko Jima, NW Okinawa, Japan. A recently developed method, the natural laboratory (sensu Hohenegger), has been applied on H. 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. Growth estimation of the larger foraminifer Heterostegina depressa by means of population dynamics. Cite this article Eder W, Woeger J, Kinoshita S, Hohenegger J, Briguglio A. For attribution, the original author(s), title, publication source (PeerJ) and either DOI or URL of the article must be cited. Licence This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, reproduction and adaptation in any medium and for any purpose provided that it is properly attributed. 2 Dipartimento di Scienze della terra, dell’ambiente e della vita (DISTAV), Università degli Studi di Genova, Genova, Italy DOI 10.7717/peerj.6096 Published Accepted Received Academic Editor Kenneth De Baets Subject Areas Marine Biology, Paleontology, Population Biology Keywords Growth estimation, Chamber building rate, Natural laboratory, Carbonate producer Copyright © 2019 Eder et al.
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