Temporal and photophysiological variations of symbiont communities in the reef-building coral, Isopora palifera
Date Issued
2007
Date
2007
Author(s)
Hsu, Chia-Min
DOI
en-US
Abstract
Isopora palifera inhabits the upper subtidal reefs where physical disturbances such as temperature and light intensity are high. In this thesis, I examined the temporal and photophysiological variations of symbiont communities in I. palifera.
Monthly variation of Symbiodinium phylotypes in I. palifera collected from March 2006 to March 2007 indicated a significant seasonal fluctuation, a consistent pattern was also observed in the samples collected from January 2000 to July 2001 in Tantzei Bay, Kenting. Nevertheless, the dominant phylotype was completely shifted from Symbiodinium D to Symbiodinium C between these two sampling periods. This reshuffling provides the evidence that symbiont communities in I. palifera could return to the dominance of “cosmopolitan” Symbiodinium C, as seen in most of the Indo-Pacific corals, during the non-bleaching period. Whereas I. palifera shuffled the dominant symbiont to the thermal-tolerant phylotype D during the recovery period right after the mass coral bleaching in 1998 and 1999.
Photophysiological responses measured in situ by Diving-PAM indicated that the tagged coral colonies showed a significant drop of maximum quantum yield (Fv/Fm) in July 2006. This drop may reflect the photoinhibition of Symbiodinium when seawater temperature and light intensity reached their threshold during summer. In contrast, the maximum reshuffling of Symbiodinoum phylotypes occurred in September (C phylotype reduced from 66.7% to 25%, but C+D phylotype increased from 33.3% to 75%). This time lag supported the scenario that phylotype reshuffling did not necessarily come with spontaneous photophysiological response. This result also implied that symbionts could provide stable energy source to the host with different symbiont compositions, and reducing photosynthetic capacity might trigger phylotype reshuffling in I. palifera.
Subjects
最大光合效能
親緣型出現率
季節性變動
限制酵素片段多型性
光合抑制
洗牌
Maximum quantum yield (Fv/ Fm)
phylotypes occurrence percentage
seasonal fluctuation
restriction fragment length polymorphism (RFLPs)
reshuffling
photoinhibition
SDGs
Type
thesis
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