Proliferation of the toxic dinoflagellate Ostreopsis cf. ovata in relation to depth, biotic substrate and environmental factors in the North West Mediterranean Sea
type: Dataset
description: In recent decades, the North West Mediterranean Sea has been seriously affected by the development of the toxic benthic dinoflagellate Ostreopsis cf. ovata, which is associated with harmful effects on human health and the environment. The present work aims to provide a large overview of the multiple environmental factors assumed to regulate or influence the growth of Ostreopsis. An intensive sampling campaign over a full annual cycle was performed along the French and Italian coasts (in six sites from Cassis to Genoa), to determine patterns of temporal and spatial distributions of both O. cf. ovata epiphytic and planktonic cells. Results highlighted substantial seasonal variations in the abundance of Ostreopsis. These variations correlated to seawater temperature, with an optimum growth temperature ranging from 23 degrees C to 27.5 degrees C. Phosphate concentration, rather than nitrogen or silicate, was also positively associated with Ostreopsis. Decreases in oxygen and increases in chlorophyll a concentrations were recorded during the summer blooming period. The maximal Ostreopsis epiphytic abundance was generally higher on Dictyota spp. than on the other two sampled macroalgae (up to 8.54 x 10(6) cells g(-1) FW), even though statistical analysis did not support a clear substrate preference. Epiphytic abundances were significantly higher at a very shallow depth (0.5 m), than at 1 and/or 3 m depths. High anthropogenic pressure (related to population density) seems to have promoted the occurrence of blooms in urbanized areas, which could partly explain the strong demarcation in Ostreopsis development between Western and Eastern sampling sites. The ecological niche of Ostreopsis cf. ovata needs precise definition, which will require further in situ and in vitro experimental studies, to determine the relative importance of distinct environmental parameters
issued: 2026-05-07T13:27:58.585135
language: en
modified: 2026-05-07T13:27:58.585140
contact point: Organization
  fn: CCSD
keyword: dinoflagellate
keyword: hab
keyword: infoeu-reposemanticsarticle
keyword: journal-articles
keyword: mediterranean-sea
keyword: ostreopsis
keyword: sdebeenvironmental-sciencesbiodiversity-and-ecology
landing page: 1568-9883

Proliferation of the toxic dinoflagellate Ostreopsis cf. ovata in relation to depth, biotic substrate and environmental factors in the North West Mediterranean Sea
type: Distribution
format: HTML
issued: 2026-05-07T13:27:58.591790
modified: 2026-05-07T13:27:58.577299
access URL: https://hal.science/hal-00926994

test_moissonnage_selune
type: Agent