TY - JOUR
T1 - Effect of UV radiation on the expulsion of Symbiodinium from the coral Pocillopora damicornis
AU - Zhou, Jie
AU - Huang, Hui
AU - Beardall, John
AU - Gao, Kunshan
PY - 2017/1/1
Y1 - 2017/1/1
N2 - The variation in density of the symbiotic dinoflagellate Symbiodinum in coral is a basic indicator of coral bleaching, i.e. loss of the symbiotic algae or their photosynthetic pigments. However, in the field corals constantly release their symbiotic algae to surrounding water. To explore the underlying mechanism, the rate of expulsion of zooxanthellae from the coral Pocillopora damicornis was studied over a three-day period under ultraviolet radiation (UVR, 280–400 nm) stress. The results showed that the algal expulsion rate appeared 10–20% higher under exposure to UV-A (320–395 nm) or UV-B (295–320 nm), though the differences were not statistically significant. When corals were exposed to UV-A and UV-B radiation, the maximum expulsion of zooxanthellae occurred at noon (10:00–13:00), and this timing was 1 h earlier than in the control without UVR. UVR stress led to obvious decreases in the concentrations of chl a and carotenoids in the coral nubbins after a three-day exposure. Therefore, our results suggested that although the UVR effect on algal expulsion rate was a chronic stress and was not significant within a time frame of only three days, the reduction in chl a and carotenoids may potentially enhance the possibility of coral bleaching over a longer period.
AB - The variation in density of the symbiotic dinoflagellate Symbiodinum in coral is a basic indicator of coral bleaching, i.e. loss of the symbiotic algae or their photosynthetic pigments. However, in the field corals constantly release their symbiotic algae to surrounding water. To explore the underlying mechanism, the rate of expulsion of zooxanthellae from the coral Pocillopora damicornis was studied over a three-day period under ultraviolet radiation (UVR, 280–400 nm) stress. The results showed that the algal expulsion rate appeared 10–20% higher under exposure to UV-A (320–395 nm) or UV-B (295–320 nm), though the differences were not statistically significant. When corals were exposed to UV-A and UV-B radiation, the maximum expulsion of zooxanthellae occurred at noon (10:00–13:00), and this timing was 1 h earlier than in the control without UVR. UVR stress led to obvious decreases in the concentrations of chl a and carotenoids in the coral nubbins after a three-day exposure. Therefore, our results suggested that although the UVR effect on algal expulsion rate was a chronic stress and was not significant within a time frame of only three days, the reduction in chl a and carotenoids may potentially enhance the possibility of coral bleaching over a longer period.
KW - Coral
KW - Expulsion
KW - Pocillopora damicornis
KW - Ultraviolet radiation
UR - http://www.scopus.com/inward/record.url?scp=84994558685&partnerID=8YFLogxK
UR - http://ac.els-cdn.com.ezproxy.lib.monash.edu.au/S101113441630776X/1-s2.0-S101113441630776X-main.pdf?_tid=30df611c-b5f2-11e6-870f-00000aacb35d&acdnat=1480396428_cc0cff1c090b743b38ed2cb3122f29c6
U2 - 10.1016/j.jphotobiol.2016.11.003
DO - 10.1016/j.jphotobiol.2016.11.003
M3 - Article
AN - SCOPUS:84994558685
SN - 1011-1344
VL - 166
SP - 12
EP - 17
JO - Journal of Photochemistry and Photobiology B: Biology
JF - Journal of Photochemistry and Photobiology B: Biology
ER -