| Summary: | 碩士 === 國立中山大學 === 海洋生物研究所 === 83 === The extent of intracolonial integration in massive hermatypic
corals was investigated by carbon and nitrogen stable isotope
analysis. The δ13C of coral tissues were higher than
zooxanthellae. Moreover, positive correlations between coral
tissues and zooxanthellae in δ13C were significant. These
results suggest that a major portion of organic carbon in coral
tissue was contributed by zooxanthellae. By using Tubastrea
aurea , an azooxanthellate coral, as control, it is estimated
that more than 80% of carbon of zooxanthellate corals in this
study were contributed by their symbiotic algae. Contrary to
δ13C, no positive correlation in δ15N was found between coral
tissues their zooxanthellae; this phenomenon suggests that
coral and zooxanthella may have relatively independent nitrogen
sources. The δ13C of coral tissues and zooxanthellae were
higher on the top of the colonies than on the side. After
several analysis comparing values in " paste " colonies which
isolate parts of the colonies, the hypothesis of environmental
effect was supported as an explanation of the difference in δ13
C between different parts (top vs side) of a colony. Different
rates of photosynthesis caused by various light intensities on
top and side of colonies is a likely explanation for δ13C
variation within a colony. No consistent difference was found
in δ15N between top and side of colonies.
|
|---|
