Title: DIVERSITY OF SYMBIODINIUM SPP. IN THE ZOANTHARIAN ZOANTHUS SANSIBARICUS ACROSS VERTICAL GRADIENTS IN THE WESTERN PACIFIC

Abstract: The zoantharian Zoanthus sansibaricus is widely distributed in the western Pacific from the intertidal zone to depths of more than 50 m. Research has indicated there is diversity in its association with endosymbiotic Symbiodinium spp., but fine-scale investigations across both depth gradients and geographic ranges are needed clarify the distribution of this diversity, as well as provide a basis for discussing the wide range of habitats and depths over which the host species thrives. In this study, we collected specimens from subtropical Okinawa, Japan, and tropical Palau, from the intertidal zone to >30 m. Molecular phylogenetic data from the non-coding region of the plastid mini-circle and other markers were contrasted between the primary locations, as well as a smaller set of samples from the Maldives, Hong Kong, and the Red Sea. In Okinawa, Z. sansibaricus in <5 m hosted two different species of Symbiodinium, while deeper colonies (>10 m) hosted another, different species, with transplant experiments suggesting no switching or shuffling between 'deep' and 'shallow' Symbiodinium. In Palau, shaded intertidal colonies in unique notch habitats hosted the same Symbiodinium as colonies from 20 m. Combined with population genetic data showing a lack of structure between host Z. sansibaricus populations across depth, these results suggest that 1) Z. sansibaricus has limited but important flexibility in its Symbiodinium associations, allowing it to exist in a variety of environments, and 2) the partitioning of Symbiodinium is driven primarily by micro-environmental light levels.

Authors: Reimer JD, Fujiwara Y, Parkinson JE

Presentation: Oral

Session: 7

Date: 06/21/16

Time: 15:00

Location: 311

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