Zeitschrift für Ozeanographie und Meeresforschung
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Abstrakt

Ecology of the Epiphytic Potentially Harmful Dinoflagellate Ostreopsis cf. ovata (Fukuyo) from Coastal Waters off Alexandria Egypt

Shimaa Hosny, Wagdy Labib

Despite macroalgae epiphytes play an important role in algal habitats, available information from Alexandria coastal waters is scarce. To evaluate the role of environmental factors on the inventory of the ephyphytic Ostreopsis cf ovata cells, its abundance on the thalli of 14 different macroalgae collected from two sites at Abou Qir rocky area was done on the basis of sampling carried out for one year. The annual maximum Ostreopsis cf. ovata cell abundance was observed in May (late-spring), reaching the maximum on the green macroalgae Ulva linza in July (mid-summer). Analysis of variance showed significant difference of abundance between seasons and hosts. Water temperature and NO ₂ , NO ₃ and PO ₄ seem the major factors affecting on abundance of Ostreopsis cf ovata. The present study documented the significant importance of Ulva sp. as the suitable host of O. ovata in Alexandria waters, in contrast with others in the Mediterranean Sea that show O. ovata most often found on Phaeophyta and Rhodophyta.