Journal of Oceanography and Marine Research
Open Access

Abstract

Epiphytic Microalgal Dynamics and Species Composition on Brown Seaweeds (Phaeophyceae) on the Northern Coast of Jeddah, Saudi Arabia

Salim Marzoog Al-Harbi

Epiphytic microalgae grow on host seaweeds. Seaweeds are multicellular macro-algae, which are abundant in intertidal zones of coastal environments. The report on epiphytic microalgae is rare in the Red Sea. Thus, an investigation on epiphytic microalgae was carried on northern coast of Jeddah, the Red Sea, Saudi Arabia. The Red Sea is narrow oceanic basin which is lying between the African and the Asian continental shelves. During the study, 4 species of seaweeds were recorded in Phaeophyceae which were Laminaria sp., Padina fraseri, Sargassum muticum and Turbinaria ornata. A total of 83 epiphytic microalgae were identified, including 76 belong to Bacillariophyceae, 5 belong to Cyanophyceae, 1 belongs to Chlorophyceae and 1 belongs to Dinophyceae. On seaweeds of Laminaria sp., the dominant epiphytes were Leptocylindrus danicus, Licmophora flabellata and Navicula ramosissma. On seaweeds Padina fraseri, the dominant epiphytes were Cylindrotheca closterium, Navicula sp., Nitzschia sp. and Prorocentrum lima and Cocconeis lineatus. On seaweeds of Sargassum muticum, the dominant epiphytes were Navicula distans, Nitzschia socialis and Navicula vanhoeffeni. On seaweeds Turbinaria ornata, the dominant epiphytes were Leptocylindrus minimus, Bacillaria paxillifer, Leptocylindrus danicus, Nitzschia hungarica and Thalassionema frauenfeldii. The host seaweeds influenced the associated diatoms mainly through its morphology and surface texture and roughness to provide a point of attachment and shelter for host-adapted species. Most of the dominant epiphytes were in smaller cell size diatoms, except Cylindrotheca closterium. The findings of the study focused on individual species of benthic marine diatoms associated with specific seaweeds species even in different regions of the Red Sea in different seasons of Saudi Arabia. These findings could be the important source for future explanation of marine eco-biogeographical phenomena in the Red Sea.