Lobata

Abstract: The lipid classes and fatty acid profiles of macrophytic algae from the Phaeophyta (Egregia menziesii), Rhodophyta (Chondracanthus canaliculatus) and Chlorophyta (Ulva lobata) were determined. Ulva lobata contained the highest amounts of lipids (20-29 mg g - 1 dry mass), followed by Egregia menziesii (9-16 mg) and Chondracanthus canaliculatus (2-3 mg), with increased lipids in winter and spring. This was reflected in total fatty acid content (14-24, 6-13 and 1-2 mg g - 1 dry mass, respectively). Major lipid classes were polar lipids (44-94 % of total lipids) and sterols (3-8 %). Higher levels of triacylglycerols occurred in Egregia menziesii during spring (22 %) and in Ulva lobata during summer (12 %). Free fatty acids were also variable (0-26 %). Triacylglycerols were not detected in Chondracanthus canaliculatus. Low levels of wax esters and diacylglyceryl ethers were detected in Ulva lobata (0.1 %). The major fatty acid common to all species was 16:0. Egregia menziesii and Chondracanthus canaliculatus contained 14:0, 18:1(n-9), 20:4(n-6) and 20:5(n-3) as major components. Egregia menziesii and Ulva lobata also contained 18:2(n-6), 18:3(n-3) and 18:4(n-3), and Chondracanthus canaliculatus and Ulva lobata contained 18:1(n-7). Large amounts of C 1 6 polyunsaturated fatty acids and the presence of 22:0 and C 2 2 polyunsaturated fatty acids were unique to U. lobata. Knowledge gained regarding macroalgal lipid composition may prove useful in raising mariculture species.

Abstract: Tentacle expansion and contraction were investigated in four zooxanthellate coral species and one azooxanthellate coral (Cladopsammia gracilis). Favia favus, Plerogyra sinuosa and Cladopsammia gracilis expand their tentacles at night, while tentacles in Goniopora lobata and Stylophora pistillata are expanded continuously. Light at wavelengths in the range 400-520 nm was most effective in eliciting full tentacle contraction in F. favus and in P. sinuosa. Higher light intensities in the range 660-700 nm also caused tentacle contractions in F. favus. Tentacles in C. gracilis did not respond to light. Zooxanthellar densities in tentacles were significantly higher in G. lobata, which has continuously expanded tentacles, than in F. favus and P. sinousa, where tentacles are expanded at night. Photosynthetic efficiency in F. favus and P. sinuosa was lower in specimens with contracted tentacles. However, in the dark, no differences were found in the maximum quantum yield of photochemistry in PSII (Fv/Fm) of the expanded versus the contracted tentacles of any of the four species. This work suggests that species whose tentacles remain continuously expanded have either dense algal populations in their tentacles, as in G. lobata, or minute tentacles, like S. pistillata. Dense algal populations in tentacles allow harvesting of light while small tentacles do not scatter light or shade zooxanthellae in the underlying body of the polyp.