δ13C and δ15N values in reef corals Porites lutea and P. cylindrica and in their epilithic and endolithic algae
- 228 Downloads
In summer 1998, shallow water corals at Sesoko Island, Japan (26°38′N, 127°52′E) were damaged by bleaching. In August 2003, partially damaged colonies of the massive Porites lutea and the branching P. cylindrica were collected at depths of 1.0–2.5 m. The species composition of epilithic algal communities on dead skeletal surfaces of the colonies (‘red turfs’, ‘green turfs’, ‘red crusts’) and the endolithic algae (living in coral skeletons) growing close to and away from living coral polyps was determined. Carbon and nitrogen stable isotope values of organic matter (δ13C and δ15N) from all six of these biological entities were determined. There were no significant differences in the isotope composition of coral tissues of the two corals, with P. lutea having δ13C of −15.3 to −9.6‰ and δ15N of 4.7–6.1‰ and P. cylindrica having similar values. Polyps in both species living close to an interface with epilithic algae had similar isotope values to polyps distant from such an interface. Despite differences in the relative abundance of the algal species in red turfs and crusts, their δ13C and δ15N values were not significantly different from each other (−18.2 to −13.9, −20.6 to −16.2, 1.1–4.3, and 3.3 to 4.9‰, respectively). The green algal turf had significantly higher δ13C values (−14.9 to −9.3‰) than that of red turfs and crusts but similar δ15N (1.2–4.1‰) to the red algae. The data do not suggest that adjoining associations of epilithic algae and coral polyps exchange carbon- and nitrogen-containing metabolites to a significant extent. The endolithic algae in the coral skeletons had δ13C values of −14.8 to −12.3‰ and δ15N of 4.0–5.4‰. Thus they did not differ significantly from the coral polyps in their carbon and nitrogen isotope values. The similarity in carbon isotope values between the coral polyps and endolithic algae may be attributed to a common source of CO2 for zooxanthellae and endolithic algae, namely, from respiration by the coral host. While it is difficult to fully interpret similarity in the nitrogen isotope composition of coral tissue and of green endolithic algae and the difference in δ15N between green epilithic and endolithic algae, the data are consistent with nitrogen-containing metabolites from the scleractinian coral serving as a significant source of nitrogen for the endolithic algae.
KeywordsDissolve Inorganic Carbon Dissolve Inorganic Nitrogen Dissolve Organic Nitrogen Coral Species Coral Tissue
This study was supported by the State Program ‘Comprehensive analyses on biodiversity in coral reef and island ecosystems in Asian and Pacific regions’ (Japan, Leader of the program Prof. Makoto Tsuchiya). We are grateful to all staff at the Sesoko Station (Ryukyu University) for use of facilities, technical help, hospitality, and facilitation of research work. The University of Dundee is a registered Scottish charity, No. SC015096.
- Deuser WG, Hunt JM (1969) Stable isotope ratios of dissolved inorganic carbon in the Atlantic. Deep Sea Res 16:221–225Google Scholar
- Muscatine L, Kaplan IR (1994) Resource partitioning by reef corals as determined from stable isotope composition II. δ15N of zooxanthellae and animal tissue versus depth. Pac Sci 48:304–312Google Scholar
- Tanaka Y, Miyajima T, Koike I, Hayashibara T, Ogawa H (2006) Translocation and conservation of organic nitrogen within the coral-zooxanthella symbiotic system of Acropora pulchra, as demonstrated by dual isotope-labeling techniques. J Exp Mar Biol Ecol 336:110–119. doi: 10.1016/j.jembe.2006.04.011 CrossRefGoogle Scholar
- Titlyanov EA, Novojilov AD, Cherbadgy II (1993) Ahnfeltia tobuchiensis: Biology, ecology, productivity. “Nauka” Moscow, 208 pGoogle Scholar
- Titlyanov EA, Kiyashko SI, Titlyanova TV, Yakovleva IM, Wada E (2006) Coral-algal competition as determined from the rate of overgrowth, physiological condition of polyps of the scleractinian coral Porites lutea, and structure of algal associations within boundary areas. Proc 10th int coral reef symp, pp 1931–1942Google Scholar
- Wang WL, Yeh HW (2003) Delta C-13 values of marine macroalgae from Taiwan. Bot Bull Acad Sin 44:107–112Google Scholar
- Williams PM, Gordon LI (1970) Carbon-13: carbon-12 ratios in dissolved and particulate organic matter in the sea. Deep-Sea Res 17:19–27Google Scholar
- Yellowlees D, Rees TA, Fitt WK (1994) Effect of ammonium-supplemented seawater on glutamine synthetase and glutamate dehydrogenase activities in host tissue and zooxanthellae of Pocillopora damicornis and on ammonium uptake rates of the zooxanthellae. Pac Sci 48:291–295Google Scholar