Different zooxanthellae types in populations of the zoanthid Zoanthus sansibaricus along depth gradients in Okinawa, Japan

作者：Kamezaki Minaho; Higa Marie; Hirose Mamiko; Suda Shoichiro; Reimer James Davis^*

来源：Marine Biodiversity, 2013, 43(1): 61-70.

DOI：10.1007/s12526-012-0119-2

• Zoanthid
• Zooxanthellae
• Okinawa
• ITS-rDNA
• Symbiodinium

Zooxanthellate zoanthid colonies of the species Zoanthus sansibaricus (Cnidaria: Anthozoa: Hexacorallia) are present both in the intertidal zone and at depths greater than 7 m at three locations (Manza, Zanpa, Sunabe) along the west coast of Okinawa, Japan. In this study, the identity of Z. sansibaricus colonies from various depths as the same species was confirmed using morphological analyses of tentacle numbers, polyp diameter, and nematocyst examination. In addition, molecular analyses of sequences of mitochondrial cytochrome oxidase subunit I and the internal transcribed spacer region 2 of ribosomal DNA (ITS2-rDNA) were performed. Surveys from 0 to 35 m depths at Manza indicated that the populations of Z. sansibaricus were discontinuous in their bathymetrical distribution, with few or no Z. sansibaricus colonies found at depths of 4-7 m. Examination of Symbiodinium (=zooxanthellae) types within Z. sansibaricus colonies by phylogenetic analyses of Symbiodinium ITS2-rDNA showed clear differences between the two populations, with some (=27 %) intertidal colonies having Symbiodinium clade A, while all deeper subtidal (> 7 m depth) colonies possessed Symbiodinium clade C (n = 18). Detailed phylogenetic analyses further indicated significant differences within Symbiodinium clade C populations over depth. From this study, it is clear that the zoanthid Z. sansibaricus has some variation in its symbiosis with Symbiodinium, potentially allowing the species to colonize different depths in the subtropical coral reef environment of Okinawa, and that its range extends far past the shallow subtidal zone as previously believed.

• 出版日期2013-3