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- Preliminary deep-sea data analysis collected at Gloria seamount, Azores-Biscay RisePublication . Tojeira, Inês; Pinto-Ribeiro, Luísa; Rafael, Teresa; Albuquerque, Mónica; Simões, Maria; Calado, António; Afonso, Andreia; Ramos, Bruno; Souto, Miguel; Bettencourt, Renato; Vasco Rodrigues, Nuno; Costa, José Lino; Cabral, Henrique; Madureira, PedroThe present study provides the first results of the exploratory research campaign to Gloria seamount (summit at 45.03°N, 15.54°W), a newly identified seamount in the NE Atlantic. New multibeam bathymetry and an 8 h remote operated vehicle footage and photography data were compiled and analyzed to give the first insights on the geological nature and benthic megafauna assemblages of Gloria seamount. Footage evidenced three distinct seafloor coverage areas, ranging from unconsolidated fine sediment with ripple marks, to increasingly coarser-grain sediment with large blocks, to outcrops with steep slopes along successive ridges, locally exhibiting volcanic structures. The deep-sea benthic assemblages differed with depth (2700−2450 m) and seafloor substrate type. In sediment habitats, pink holothurians (Elpidiidae) and brittle stars (Ophiuroidea) were recorded, whereas in hard substrates, sponges (Hexactinellida and Demospongiae) and stalked crinoids (Crinoidea) were mixed with distinct coral specimens, such as bamboo corals (Isidiidae) and Coralliidae (Scleralcyonacea). The integration of these data contribute to the geo-habitats knowledge of an unexplored seamount.
- Catostylus tagi (Class: Scyphozoa, Order: Discomedusae, Suborder: Rhizostomida, Family: Catostylidae) life cycle and first insight into its ecologyPublication . Gueroun, Sonia K.M.; Torres, Tatiana M.; Santos, Antonina dos; Vasco Rodrigues, Nuno; Canning-Clode, João; Andrade, CarlosJellyfish proliferations, which are conspicuous and natural events, cause blooms that may lead to severe consequences for anthropogenic activities and ecosystem structure and functioning. Although research during the last decade has focused on factors influencing the different jellyfish life stages, few species currently have their full life cycle known. In this context, we describe for the first time the developmental stages in the life cycle of Catostylus tagi, from planula to young medusa, reared in the laboratory. The species displays the typical Rhizostomida metagenetic life cycle. Mature scyphistomae display 16 tentacles and a total body length of 1.5 ± 0.2 mm. Only podocyst production and strobilation were observed. Strobilation, occurring continuously under laboratory conditions, was mainly polydisc. The eight-rayed typical ephyrae, with a total body diameter of 2.4 ± 0.4 mm at detachment, showed development typical of the Rhizostomida. As a first step in studying this species’ ecology, we also present preliminary assessments of: (i) the influence of different temperature and salinity regimes on planulae survival, settlement and metamorphosis and (ii) the effect of temperature and diet on asexual reproduction. The results showed a high tolerance of planulae to a wide range of salinities (15‰to 25‰), while polyp development was significantly faster at higher temperature (20–25º C). Strobilation onset was 2–3 times faster at 20º C (10.6 ± 5.4 to 15 ± 6.6 day at various tested diet) than at 15º C (32.2 ± 3 day). Feeding was a key factor as unfed polyps never underwent strobilation during the trial. Finally, we present the spatial and seasonal distribution of C. tagi in the Tagus estuary (Portugal) in 2019, showing its occurrence throughout the year (except in April), with most observations recorded on the northern shoreline. As C. tagi shows the ability to form blooms and a wide tolerance for temperature and salinity (for planulae and medusae stage), it is essential to understand its life cycle.