title: Ostreopsis cf. ovata dynamics in the NW Mediterranean Sea in relation to biotic and abiotic factors.
abstract: An expansion of the distribution of Ostreopsis cf. ovata, a dinoflagellate which produces palytoxin-like compounds, has been reported in recent years. Economical and social interests are affected by blooms, as they are responsible for respiratory and skin problems in humans and may cause damage to marine organisms. In order to identify the most influential environmental factors that trigger proliferations of O. cf. ovata in the area of the adjacent shallow rocky coast of the Ebro Delta (NW Mediterranean Sea) a three-year survey was performed on the metaphytic microalgae community growing on the macrophytes Jania rubens and Corallina elongata. Small-size diatoms were more abundant than dinoflagellates; O. cf. ovata was identified as the only species present from the genus. Seawater temperature was the primary driver defining the ecological niche of O. cf. ovata. Freshwater and groundwater fluxes were more pronounced in southern than in northern sites, which may have resulted in a distinct O. cf. ovata spatial distribution, with the highest records of abundance and more frequent blooms in the north. In consequence, negative correlations between the abundance of O. cf. ovata and nitrate concentrations and significant positive correlation with salinity were observed. The temporal pattern of O. cf. ovata dynamics from mid-July to early-November is probably due to the fact that this species is observed only above a certain threshold temperature of seawater. Metaphytic cells of O. cf. ovata were smaller in the northern site than in the south, possibly as a result of an increase in cell division, coinciding with higher abundance, and this could be an indicator of favorable conditions. Toxicity in planktonic cells was negatively correlated with cell abundance in the water column, achieving maximum concentrations of 25pg. PLTX eqcell(-1).
authors.affiliation: IRTA, Carretera de Poble Nou, km 5.5, 43540 Sant Carles de la Ràpita, Spain.
authors.forename: Olga
authors.initials: O
authors.lastname: Carnicer
authors.affiliation: IRTA, Carretera de Poble Nou, km 5.5, 43540 Sant Carles de la Ràpita, Spain; IFREMER, DYNECO-PELAGOS Centre de Brest, Pointe du Diable BP70, 29280 Plouzane, France.
authors.forename: Carles
authors.initials: C
authors.lastname: Guallar
authors.affiliation: IRTA, Carretera de Poble Nou, km 5.5, 43540 Sant Carles de la Ràpita, Spain.
authors.forename: Karl B
authors.initials: KB
authors.lastname: Andree
authors.affiliation: IRTA, Carretera de Poble Nou, km 5.5, 43540 Sant Carles de la Ràpita, Spain.
authors.forename: Jorge
authors.initials: J
authors.lastname: Diogène
authors.affiliation: IRTA, Carretera de Poble Nou, km 5.5, 43540 Sant Carles de la Ràpita, Spain. Electronic address: margarita.fernandez@irta.cat.
authors.forename: Margarita
authors.initials: M
authors.lastname: Fernández-Tejedor
mesh_terms: D000178:Acrylamides / Q000032:analysis / Q000633:toxicity; D058448:Biota / Q000187:drug effects; D003064:Cnidarian Venoms; D017377:Diatoms / Q000187:drug effects / Q000254:growth & development; D004141:Dinoflagellida / Q000254:growth & development*; D004784:Environmental Monitoring / Q000379:methods*; D057097:Harmful Algal Bloom; D008522:Mediterranean Sea; D058086:Microalgae / Q000187:drug effects / Q000254:growth & development; D011157:Population Dynamics; D025341:Principal Component Analysis; D054712:Salinity; D012623:Seawater / Q000737:chemistry*; D013030:Spain; D013696:Temperature; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000633:toxicity; D000095702:Polyether Toxins
chemical_list: D000178:Acrylamides; D003064:Cnidarian Venoms; D014874:Water Pollutants, Chemical; C010272:palytoxin; D000095702:Polyether Toxins
keywords: Mediterranean; Nutrients; Ostreopsis cf. ovata; Palytoxin; Salinity; Temperatura