Effects of cyanide on coral photosynthesis: implications for identifying the cause of coral bleaching and for assessing the environmental effects of cyanide fishing

Jones, Ross J. and Hoegh-Guldberg, Ove (1999) Effects of cyanide on coral photosynthesis: implications for identifying the cause of coral bleaching and for assessing the environmental effects of cyanide fishing. Marine Ecology-progress Series, 177 83-91. doi:10.3354/meps177083


Author Jones, Ross J.
Hoegh-Guldberg, Ove
Title Effects of cyanide on coral photosynthesis: implications for identifying the cause of coral bleaching and for assessing the environmental effects of cyanide fishing
Journal name Marine Ecology-progress Series   Check publisher's open access policy
ISSN 1616-1599
0171-8630
Publication date 1999
Sub-type Article (original research)
DOI 10.3354/meps177083
Open Access Status DOI
Volume 177
Start page 83
End page 91
Total pages 9
Place of publication Oldendorf, Germany
Publisher Inter-Research
Language eng
Abstract Modulated chlorophyll fluorescence techniques were used to examine the effects of cyanide (NaCN) from cyanide fishing on photosynthesis of the symbiotic algae (zooxanthellae) located within the tissues of the zooxanthellate hard coral Plesiastrea versipora. Incubating corals for 3 h in a cyanide concentration of >10(-5) M NaCN under a saturating light intensity (photosynthetically active radiation [PAR] intensity of 250 mu mol quanta m(-2) s(-1)) caused a long-term decrease in the ratio of variable to maximal fluorescence (dark-adapted F-v/F-m). The effect of cyanide on dark-adapted F-v/F-m was Light dependent; thus F-v/F-m only decreased in corals exposed to 10(-4) M NaCN for 3 h under PAR of 250 mu mol quanta m(-2) s(-1). In corals where dark-adapted F-v/F-m was significantly lowered by cyanide exposure, we observed significant loss of zooxanthellae from the tissues. causing the corals to discolour (bleach). To further examine the light-dependent effect of cyanide and its relation to loss of zooxanthellae, corals were exposed to 10-4 M NaCN or seawater only (control), either in darkness or under 250 mu mol quanta m(-2) s(-1). ill significant decrease in dark-adapted F-v/F-m and loss of zooxanthellae only occurred in corals exposed to cyanide in the light. These results suggest cyanide causes the dissociation of the symbiosis (bleaching) by affecting photosynthesis of the zooxanthellae. Quenching analysis using the saturation-pulse technique revealed the development of high levels of non-photochemical quenching in cyanide-exposed coral. This result is consistent with the known property of cyanide as an inhibitor of the dark reactions of the Calvin cycle, specifically as an inhibitor of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco). Therefore, chronic photoinhibition and an impairment of photosynthesis of zooxanthellae provides an important 'signal' to examine the environmental effects of cyanide fishing during controlled releases in situ.
Keyword Ecology
Marine & Freshwater Biology
Oceanography
Bleaching
Cyanide
Zooxanthellae
Coral
Chlorophyll Fluorescence
Chlorophyll Fluorescence
Electron Flow
Reef Corals
Light
Zooxanthellae
Temperature
Photoinhibition
Phytoplankton
Inactivation
Fluorometer
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Unknown

Document type: Journal Article
Sub-type: Article (original research)
Collection: Centre for Marine Studies Publications
 
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Created: Mon, 13 Aug 2007, 10:56:06 EST