Combined effects of temperature, irradiance and pH on Teleaulax amphioxeia (Cryptophyceae) physiology and feeding ratio for its predator Mesodinium rubrum (Ciliophora)
|Author(s)||Gaillard Sylvain1, Charrier Aurelie2, Malo Florent1, Carpentier Liliane1, Bougaran Gael2, Hégaret Helene3, Réveillon Damien1, Hess Philipp1, Séchet Veronique1|
|Affiliation(s)||1 : IFREMER Laboratoire Phycotoxines rue de l’Ile d’Yeu, F‐44311 Nantes 03, France
2 : IFREMER Laboratoire Physiologie et Biotechnologie des Algues (PBA) rue de l’Ile d’Yeu, F‐44311 Nantes 03, France
3 : IUEM‐UBO Laboratoire des sciences de l’environnement marin (LEMAR) Technopôle Brest Iroise 29280 Plouzané ,France
|Source||Journal Of Phycology (0022-3646) (Wiley), 2020-06 , Vol. 56 , N. 3 , P. 775-783|
|Keyword(s)||Dinophysis, ecophysiology, full factorial design, global change, Mesodinium rubrum, Teleaulax amphioxeia|
The cryptophyte Teleaulax amphioxeia is a source of plastids for the ciliate Mesodinium rubrum and both organisms are members of the trophic chain of several species of Dinophysis. It is important to better understand the ecology of organisms at the first trophic levels before assessing the impact of principal factors of global change on Dinophysis spp. Therefore, combined effects of temperature, irradiance and pH on growth rate, photosynthetic activity and pigment content of a temperate strain of T. amphioxeia were studied using a full factorial design (central composite design 23*) in 17 individually controlled bioreactors. The derived model predicted an optimal growth rate of T. amphioxeia at a light intensity of 400 µmol photons · m‐2 · s‐1, more acidic pH (7.6) than the current average and a temperature of 17.6°C. An interaction between temperature and irradiance on growth was also found, while pH did not have any significant effect. Subsequently, to investigate potential impacts of prey quality and quantity on the physiology of the predator, M. rubrum was fed two separate prey: predator ratios with cultures of T. amphioxeia previously acclimated at two different light intensities (100 and 400 µmol photons · m‐2 · s‐1). M. rubrum growth appeared to be significantly dependant on prey quantity while effect of prey quality was not observed. This multi‐parametric study indicated a high potential for a significant increase of T. amphioxeia in future climate conditions but to what extent this would lead to increased occurrences of Mesodinium spp. and Dinophysis spp. should be further investigated.