Effect of light on photosynthetic efficiency of sequestered chloroplasts in intertidal benthic foraminifera (Haynesina germanica and Ammonia tepida)

Type Article
Date 2016
Language English
Author(s) Jauffrais ThierryORCID1, Jesus BrunoORCID2, 3, Metzger Edouard1, Mouget Jean-Luc4, Jorissen FransORCID1, Geslin Emmanuelle1
Affiliation(s) 1 : Univ Angers, UMR CNRS LPG BIAF 6112, Bioindicateurs Actuels & Fossiles, 2 Blvd Lavoisier, F-49045 Angers 1, France.
2 : Univ Nantes, Lab Mer Mol Sante, EA2160, 2 Rue Houssiniere, F-44322 Nantes 3, France.
3 : Campo Grande Univ Lisboa, Fac Sci, BioISI Biosyst & Integrat Sci Inst, P-1749016 Lisbon, Portugal.
4 : Univ Maine, Lab Mer Mol Sante, EA2160, Ave O Messiaen, F-72085 Le Mans 9, France.
Source Biogeosciences (1726-4170) (Copernicus Gesellschaft Mbh), 2016 , Vol. 13 , N. 9 , P. 2715-2726
DOI 10.5194/bg-13-2715-2016
WOS© Times Cited 35
Abstract

Some benthic foraminifera have the ability to incorporate functional chloroplasts from diatoms (kleptoplasty). Our objective was to investigate chloroplast functionality of two benthic foraminifera (Haynesina germanica and Ammonia tepida) exposed to different irradiance levels (0, 25, 70 mot photon m(-2) s(-1)) using spectral reflectance, epifluorescence observations, oxygen evolution and pulse amplitude modulated (PAM) fluorometry (maximum photosystem II quantum efficiency (Fv/Fm) and rapid light curves (RLC)). Our results clearly showed that H. germanica was capable of using its kleptoplasts for more than 1 week while A. tepida showed very limited kleptoplastic ability with maximum photosystem II quantum efficiency (Fv/Fm = 0.4), much lower than H. germanica and decreasing to zero in only 1 day. Only H. germanica showed net oxygen production with a compensation point at 24 mmol photon m(-2) s(-1) and a production up to 1000 pmol 02 cell(-1) day(-1) at 300 mot photon m(-2) s(-1). Haynesina germanica Fv/Fm slowly decreased from 0.65 to 0.55 in 7 days when kept in darkness; however, it quickly decreased to 0.2 under high light. Kleptoplast functional time was thus estimated between 11 and 21 days in darkness and between 7 and 8 days at high light. These results emphasize that studies about foraminifera kleptoplasty must take into account light history. Additionally, this study showed that the kleptoplasts are unlikely to be completely functional, thus requiring continuous chloroplast resupply from foraminifera food source. The advantages of keeping functional chloroplasts are discussed but more information is needed to better understand foraminifera feeding strategies.

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Jauffrais Thierry, Jesus Bruno, Metzger Edouard, Mouget Jean-Luc, Jorissen Frans, Geslin Emmanuelle (2016). Effect of light on photosynthetic efficiency of sequestered chloroplasts in intertidal benthic foraminifera (Haynesina germanica and Ammonia tepida). Biogeosciences, 13(9), 2715-2726. Publisher's official version : https://doi.org/10.5194/bg-13-2715-2016 , Open Access version : https://archimer.ifremer.fr/doc/00457/56899/