Effects of hypo-osmosis on the coral Stylophora pistillata: nature and cause of 'low-salinity bleaching'
2003; Inter-Research; Volume: 253; Linguagem: Inglês
10.3354/meps253145
ISSN1616-1599
Autores Tópico(s)Coastal wetland ecosystem dynamics
ResumoMEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 253:145-154 (2003) - doi:10.3354/meps253145 Effects of hypo-osmosis on the coral Stylophora pistillata: nature and cause of Œlow-salinity bleaching¹ Ailsa P. Kerswell1,2,*, Ross J. Jones1 1Centre for Marine Studies, The University of Queensland, St Lucia, Queensland 4072, Australia 2Present address: School of Marine Biology and Aquaculture, James Cook University, Townsville, Queensland 4811, Australia *Email: ailsa.kerswell@jcu.edu.au ABSTRACT: The response of the scleractinian coral Stylophora pistillata to short-term (min to h) and long-term (d) exposure to reduced-salinity seawater was examined. Pulse Amplitude Modulated (PAM) chlorophyll fluorescence techniques were used to assess the photosynthetic efficiency of the symbiotic dinoflagellates (dark-adapted Fv/Fm) in the coral tissues (in hospite) before, during and after exposure. Exposure to reduced-salinity seawater caused a marked reduction in efficiency (the ratio of variable [Fv] to maximal [Fm] fluorescence), and there was an apparent link between a reduction in dark-adapted Fv/Fm and a loss of symbiotic dinoflagellates from the corals. The reduction in Fv/Fm of the symbiotic algae and subsequent dissociation of the coral-algal symbiosis (coral bleaching) occurred during exposure to reduced-salinity seawater in either the light or dark. The results demonstrate that bleaching in response to low-salinity seawater is a truly sublethal response, contrary to a recent suggestion. The study also suggests that bleaching of corals in response to low-salinity seawater may not involve the passive loss of algal symbionts and that an impairment of the capacity of the algal symbionts for photosynthesis represents a common Œcue¹ initiating the dissociation of the coral-algal symbiosis during exposure to sub-optimal conditions. This study demonstrates how exposure to low-salinity seawater alone can cause some of the symptoms commonly attributed to temperature anomalies and anthropogenic pressures on coral reefs. KEY WORDS: Coral bleaching · Symbiotic dinoflagellates · Salinity · Chlorophyll fluorescence Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 253. Online publication date: May 15, 2003 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2003 Inter-Research.
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