Loss of zooxanthellae in a coral under high seawater temperature and nutrient enrichment

Yasuaki Tanaka, Mayuri Inoue, Takashi Nakamura, Atsushi Suzuki, Kazuhiko Sakai

Research output: Contribution to journalArticlepeer-review

16 Citations (Scopus)


To investigate the effect of nutrient concentrations on coral-algal symbiosis under thermal stress, the abundance and release of zooxanthellae in the coral Acropora tenuis were quantified under laboratory conditions. The coral fragments were first cultured in either low-nutrient (LN) or high-nutrient (HN) seawater condition at 27°C for 25days and the seawater temperature was then elevated and kept at 31°C for 1week for both nutrient conditions. Nutrient enrichment at 27°C increased the densities of symbiotic algae and chlorophyll a and the algal release rates (AR) from the host coral to the ambient seawater. The percentage of algal release rate to the standing stock (AR%) was approximately 0.015%h-1 for both nutrient conditions at 27°C. After the seawater temperature was elevated to 31°C, the densities of zooxanthellae in the corals decreased by 21-61%, and AR and AR% increased. The corals in HN lost more zooxanthellae per unit surface area than those in LN, but the lost percentages were not significantly different between LN and HN. AR% was also not significantly different between LN and HN at 31°C. These results indicated that the percentage rate of symbiotic algal loss was not affected by the nutrient condition, implying that nutrient incorporation itself would not accelerate coral bleaching susceptibility.

Original languageEnglish
Pages (from-to)220-225
Number of pages6
JournalJournal of Experimental Marine Biology and Ecology
Publication statusPublished - Aug 2014


  • Algal density
  • Algal release
  • Coral
  • Nutrients
  • Seawater temperature
  • Zooxanthellae

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Aquatic Science


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