Marine Ecology Progress Series
MEPS is a leading hybrid research journal on all aspects of marine, coastal and estuarine ecology. Priority is given to outstanding research that advances our ecological understanding.
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DOI: https://doi.org/10.3354/meps07360
copiedSeasonal variation in the photo-physiology of homogeneous and heterogeneous Symbiodinium consortia in two scleractinian corals
ABSTRACT: Seasonal variation in the composition of the algal endosymbiont community and photo-physiology was determined in the corals Pocillopora damicornis, which show high local fidelity to one symbiont type (Symbiodinium C1), and Acropora valida, with a mixed Symbiodinium symbiont community, comprising members of both clades A and C. The relative abundances of Symbiodinium types varied over time. A significant decline in symbiont densities in both coral species during the summer of 2005 coincided with a NOAA ‘hotspot’ warning for Heron Island. This also coincided with a relative increase in the presence and dominance of clade A in A. valida, particularly in sun-adapted surfaces. The effective quantum yield of Photosystem II (ΦPSII) suggested that sun-adapted surfaces of P. damicornis are more sensitive than shade-adapted surfaces to combined effects of higher temperature and irradiance in summer. Xanthophyll cycling was greater in P. damicornis than A. valida, irrespective of branch position and sampling time; this may be a mechanism by which P. damicornis compensates for its fidelity to Symbiodinium C1. Furthermore, xanthophyll de-epoxidation in P. damicornis symbionts was greater in sun-adapted than shade-adapted surfaces, correlating with non-photochemical quenching (NPQRLC). No variation was found in A. valida, indicating that resident symbiont communities may not have been physiologically compromised, perhaps as a result of changes in the composition of the Symbiodinium community consortia.
KEYWORDS
K. E. Ulstrup (Co-author)
- Institute for Water & Environmental Resource Management, Department of Environmental Science, University of Technology, Sydney, PO Box 123, Broadway, New South Wales 2007, Australia
- Australian Institute of Marine Science, PMB No. 3, Townsville MC, Queensland 4810, Australia
R. Hill (Co-author)
- Institute for Water & Environmental Resource Management, Department of Environmental Science, University of Technology, Sydney, PO Box 123, Broadway, New South Wales 2007, Australia
M. J. H. van Oppen (Co-author)
- Australian Institute of Marine Science, PMB No. 3, Townsville MC, Queensland 4810, Australia
A. W. D. Larkum (Co-author)
- School of Biological Sciences (A08), University of Sydney, New South Wales 2006, Australia
P. J. Ralph (Co-author)
- Institute for Water & Environmental Resource Management, Department of Environmental Science, University of Technology, Sydney, PO Box 123, Broadway, New South Wales 2007, Australia