Ostreopsis cf. ovata Bloom in Currais, Brazil: Phylogeny, Toxin Profile and Contamination of Mussels and Marine Plastic Litter

Abstract

Ostreopsis cf. ovata is a toxic marine benthic dinoflagellate responsible for harmful blooms affecting ecosystem and human health, mostly in the Mediterranean Sea. In this study we report the occurrence of a summer O. cf. ovata bloom in Currais, a coastal archipelago located on the subtropical Brazilian coast (~25° S). This bloom was very similar to Mediterranean episodes in many aspects: (a) field-sampled and cultivated O. cf. ovata cells aligned phylogenetically (ITS and LSU regions) along with Mediterranean strains; (b) the bloom occurred at increasing temperature and irradiance, and decreasing wind speed; (c) cell densities reached up to 8.0 × 104 cell cm−2 on fiberglass screen and 5.6 × 105 cell g−1 fresh weight on seaweeds; (d) and toxin profiles were composed mostly of ovatoxin-a (58%) and ovatoxin-b (32%), up to 35.5 pg PLTX-eq. cell−1 in total. Mussels were contaminated during the bloom with unsafe toxin levels (up to 131 µg PLTX-eq. kg−1). Ostreopsis cells attached to different plastic litter, indicating an alternate route for toxin transfer to marine fauna via ingestion of biofilm-coated plastic debris.

Ostreopsis cf. ovata (Dinophyceae) Molecular Phylogeny, Morphology, and Detection of Ovatoxins in Strains and Field Samples from Brazil

“…In the current study, O. cf. ovata cells with a small suture between plates 3 and 5" or just touching in a point were observed in cultures of strains UNR-05 and UNR-10, similar to cells depicted by Tibiriçá et al [30] in their Figure 4B,F. The shape of plate 4 was quite variable at the suture between this plate and plate 3 ( Figure 2F-G,J-K).…”

“…ovata subclade A together with sequences of strains from the Mediterranean Sea, the NE Atlantic (Canary Island and Portugal) as well as the SE Atlantic (Rio de Janeiro, Bahia and São Paulo in Brazil) and Japan. This is the Mediterranean/Atlantic/Pacific (AMP) clade as described by Zhang et al [33] and Tibiriçá et al [30]. Its sister subclade (B) contained three sequences, including strain UNR-10 isolated from the Brazilian Northeast coast, strain VGO614 from Madeira Island (Portugal) and strain KC17 from the Mediterranean Sea (Greece) ( Figure 5).…”

“…The shape of plate 4 was quite variable at the suture between this plate and plate 3 ( Figure 2F-G,J-K). In some cells of strain UNR-10 plate 4" presented a curved suture between plates 3 and 4 ( Figure 2J-K), a characteristic proposed as a distinguishing feature for O. fattorussoi, but then proved to be variable, as discussed by Tibiriçá et al [30]. Moreover, in these cells of strain UNR-10 ( Figure 2E-F) plate 2 extended between plates 2" and 3 , being longer than the APC plate, as already observed for other specimens of the O. cf.…”

“…Moreover, in these cells of strain UNR-10 ( Figure 2E-F) plate 2 extended between plates 2" and 3 , being longer than the APC plate, as already observed for other specimens of the O. cf. ovata phylogenetic clade by Penna et al [10], Zhang et al [33] and Tibiriçá et al [30]. In the observed cells of strain VGO614 plate 2 did not extend between plates 2" and 3 .…”

“…Massive blooms of O. cf. ovata have been observed at the remote equatorial oceanic island of St. Paul's Rocks [29] and at the coastal subtropical Currais Archipelago [30]. High O. cf.…”