Variable photo-physiological performance of macroalgae and seagrasses from Saya de Malha and Nazareth Banks, Mascarene Plateau

The photosynthetic performance of macroalgae and seagrasses related to their body parts, depth colours from the poorly-studied Saya de Malha Nazareth Banks on Mascarene Plateau was investigated in this study. Two seagrass (Thalassodendron ciliatum Halophila decipiens) seven species (Caulerpa cupressoides, Acrosorium ciliolatum, Dictyosphaeria cavernosa, Halimeda opuntia, Ulva sp., Udotea orientalis palmetta) were collected using five Van Veen grabs attached Video-Assisted Multi-Sampler (VAMS) 29-79 m depths May during FAO EAF-Nansen Research Programme 2018. measured a Diving-Pulse-Amplitude-Modulated (D-PAM) fluorometer parameters included effective quantum yield at photosystem II (PSII) (ΦPSII), relative maximum electron transport rate (rETRm), efficiency (α), photoinhibition (β), saturating light level (Ek), non-photochemical quenching (NPQmax). All photo-physiological varied significantly T. C. cupressoides across parts. However, variation with seawater not significant for NPQmax β seagrass, ΦPSII, rETRm macroalgae. Photo-physiological functioning leaf optimal 40 m. frond stolon decreased remained unchanged, respectively, 79 when compared that 29 whitish lobes H. opuntia 31 exhibited lower performance, terms rETRm,α Ek, than greenish lobes. These findings provide first insight seaplant parts-, depth- colour-related Plateau.