Calcification of Calcidiscus leptoporus under nitrogen and phosphorus limitation

Abstract

This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues.Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. The coccolithophore Calcidiscus leptoporus was grown in batch culture under nitrogen (N) as well as phosphorus (P) limitation. Growth rate, particulate inorganic carbon (PIC), particulate organic carbon (POC), particulate organic nitrogen (PON), and particulate organic phosphorus (POP) production were determined and coccolith morphology was analysed. While PON production decreased by 70% under N-limitation and POP production decreased by 65% under P-limitation, growth rate decreased by 33% under N-as well as P-limitation. POC as well as PIC production (calcification rate) increased by 27% relative to the control under P-limitation, and did not change under N-limitation. Coccolith morphology did not change in response to either P or N limitation. While these findings, supported by a literature survey, suggest that coccolith morphogenesis is not hampered by either P or N limitation, calcification rate might be. The latter conclusion is in apparent contradiction to our data. We discuss the reasons for this inference.

Physiology regulates the relationship between coccosphere geometry and growth phase in coccolithophores

“…Mean exponential growth rates for C. braarudii at 15 • C were 0.68 d −1 . These values are well within the ranges reported in other studies carried out at similar temperatures for Calcidiscus (Langer et al, 2006;Buitenhuis et al, 2008;Fiorini et al, 2010Fiorini et al, , 2011Langer et al, 2012;Candelier et al, 2013;Müller et al, 2014) and H. carteri (Stoll et al, 2002;. Exponential growth rates of 0.4-0.5 d −1 signify that roughly half of the culture population undergoes cell division each day.…”

Insight into <i>Emiliania huxleyi</i> coccospheres by focused ion beam sectioning

“…A widely held, but by no means uncontested (Langer et al, 2012;Langer et al, 2013b), notion is that nutrient limitation leads to increased calcification rate, which in turn leads to a higher overall cell density and thus increased sinking rate (Baumann et al, 1978). Indeed, several studies have shown an increase in E. huxleyi's PIC / POC ratio due to nutrient limitation regardless of the calcification rate (Paasche, 1998).…”

On culture artefacts in coccolith morphology

“…These measures ensure robust, unbiased results (Langer et al 2006;Langer and Benner 2009;Langer and Bode 2011;Langer et al 2012). Recently, it was shown that results based on an objective, biometrical malformation index compare well with the classical, subjective categorization (Bach et al 2012).…”