Field observation of Ornithocercus spp. (Dinophysiales, Dinophyta): reproductive stages and phased cell division (South Atlantic Ocean, Brazil)

• Published in: Tropical Oceanography
• Main Authors: Aquino, Eveline Pinheiro de, Silva, Marcos Honorato da, Feitosa, Fernando Antônio do Nascimento, Koening, Maria Luise, Passavante, José Zanon de Oliveira
• Format: Article in Journal/Newspaper
• Language: Portuguese
• Published: Universidade Federal de Pernambuco 2014
• Subjects: Phytoplankton; Dinoflagellate; Nictemeral variation; South Atlantic Ocean
• Online Access: https://periodicos.ufpe.br/revistas/TROPICALOCEANOGRAPHY/article/view/5812; https://doi.org/10.5914/tropocean.v42i2.5812

Studies of the marine dinoflagellates life cycle has been limited. Cell division isoften initiated at specific times of the day (phased cell division). This study report the stages of cell division (megacytic zone and dorsal megacytic bridge) in Ornithocercus population from the South Atlantic Ocean (Archipelago of Fernando de Noronha) at different times of the day. The samples were collected every 3h, covering 24h, from a two fixed samplings stations, during the years 2010 and 2012. The plankton net (20μm mesh size) was dragged vertically. The dividing cells of Ornithocercus was registered. Were identified O. magnificus Stein, O. thumii (Schmidt) Kofoid & Skogsberg, O. quadratus Schütt, and O steinii Schütt, which the phased cell division occurred and presented at least one of the cell division stages. O. quadratus occurred at a wide range of sampling times, extending from before, during, and after dawn, to during and after sunset.