Toxin content of Ostreopsis cf. ovata depends on bloom phases, depth and macroalgal substrate in the NW Mediterranean Sea

Type Article
Date 2020-02
Language English
Author(s) Gémin Marin-Pierre1, Réveillon DamienORCID1, Hervé FabienneORCID1, Pavaux Anne-Sophie2, Tharaud Maxime1, Séchet VeroniqueORCID1, Bertrand Samuel3, Lemée Rodolphe2, Amzil Zouher1
Affiliation(s) 1 : IFREMER – Phycotoxins Laboratory, F- 44311 Nantes 03, France
2 : Sorbonne Université, CNRS, Laboratoire d’Océanographie de Villefranche, UMR 7093, BP 28, F-06230 Villefranche-sur-Mer, France
3 : Groupe Mer, Molécules, Santé-EA 2160, UFR des Sciences Pharmaceutiques et Biologiques, Université de Nantes, Nantes-cedex 1 44035, France
Source Harmful Algae (1568-9883) (Elsevier BV), 2020-02 , Vol. 92 , P. 101727 (9p.)
DOI 10.1016/j.hal.2019.101727
WOS© Times Cited 6
Keyword(s) Dinoflagellate, Benthic HABs, Ostreopsis cf. ovata, Ovatoxins, Mediterranean Sea
Abstract

Over the last fifteen years, blooms of the genus Ostreopsis have been reported more frequently and at higher abundances in the Mediterranean area. Ostreopsis cf. ovata is known to produce ovatoxins (OVTXs), structural analogues of palytoxin, which is one of the most potent non-polymeric toxins. However, the production of OVTXs is poorly characterized in situ. The present study focuses on toxin content and profile according to the bloom phase during summer 2017 in Villefranche-sur-Mer, France (NW Mediterranean Sea), depth (from 0.5 to 5 m) and three different macroalgal substrates of this epiphytic dinoflagellate (Padina pavonica, Dictyota spp. and Halopteris scoparia). Ovatoxin quantification of all samples was performed by liquid chromatography coupled to tandem mass spectrometry (LC–MS/MS). The bloom started at the end of June and declined in mid-July, showing the typical seasonal pattern of the NW Mediterranean Sea area. The peak was observed on the 10 July with 1.8 × 106 cells/g FW and 1.7 × 104 cells/L for benthic and planktonic cells, respectively. Total toxin content of cells, collected using artificial substrates, increased during the exponential and stationary growth phases. After reaching a maximum concentration of 9.2 pg/cell on 18 July, toxin concentration decreased and remained stable from 25 July until the end of monitoring. A decreasing trend of the abundance and of the associated total toxin content was noted with depth. Finally, the decreasing order of maximal epiphytic concentration of O. cf. ovata was: Dictyota spp. (8.3 × 105 cells/g FW), H. scoparia (3.1 × 105 cells/g FW) and P. pavonica (1.6 × 105 cells/g FW). Interestingly, the highest OVTX quota was obtained in cells present on Halopteris scoparia, then on Dictyota spp. and Padina pavonica. This suggests that the nature of the macroalgal substrate influences both growth and toxin production of O. cf. ovata and further work will be required to understand the underlying mechanisms (e.g., competition for nutrition, pH or allelopathic interaction). However, the toxin profiles (i.e., the proportion of each ovatoxin analogue) were not affected by any of the studied parameters (bloom phase, depth, macroalgae or artificial substrates).

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Gémin Marin-Pierre, Réveillon Damien, Hervé Fabienne, Pavaux Anne-Sophie, Tharaud Maxime, Séchet Veronique, Bertrand Samuel, Lemée Rodolphe, Amzil Zouher (2020). Toxin content of Ostreopsis cf. ovata depends on bloom phases, depth and macroalgal substrate in the NW Mediterranean Sea. Harmful Algae, 92, 101727 (9p.). Publisher's official version : https://doi.org/10.1016/j.hal.2019.101727 , Open Access version : https://archimer.ifremer.fr/doc/00614/72566/