Abstract
Light is often the most abundant resource within the nutrient-poor
waters surrounding coral reefs. Consequently, zooxanthellae (
Symbiodinium spp.) must continually photoacclimate to optimise
productivity and ensure coral success. In situ coral photobiology is
becoming dominated by routine assessments using state-of-the-art
non-invasive bio-optical or chlorophyll a fluorescence (bio-physical)
techniques. Multiple genetic types of Symbiodinium are now known to
exist; however, little focus has been given as to how these types differ
in terms of characteristics that are observable using these techniques.
Therefore, this investigation aimed to revisit and expand upon a pivotal
study by Iglesias-Prieto and Trench (1994) by comparing the
photoacclimation characteristics of different Symbiodinium types based
on their bio-physical (chlorophyll a fluorescence, reaction centre
counts) and bio-optical (optical absorption, pigment concentrations)
‘signatures’. Signatures described here are unique to
Symbiodinium type and describe phenotypic responses to set conditions,
and hence are not suitable to describe taxonomic structure of in hospite
Symbiodinium communities. In this study, eight Symbiodinium types from
clades and sub-clades (A-B, F) were grown under two PFDs (Photon Flux
Density) and examined. The photoacclimation response by Symbiodinium was
highly variable between algal types for all bio-physical and for many
bio-optical measurements; however, a general preference to modifying
reaction centre content over effective antennae-absorption was observed.
Certain bio-optically derived patterns, such as light absorption, were
independent of algal type and, when considered per photosystem, were
matched by reaction centre stoichiometry. Only by better understanding
genotypic and phenotypic variability between Symbiodinium types can
future studies account for the relative taxonomic and physiological
contribution by Symbiodinium to coral acclimation.
Original language | English |
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Pages (from-to) | 179-195 |
Number of pages | 17 |
Journal | Coral Reefs |
Volume | 28 |
Issue number | 1 |
DOIs | |
Publication status | Published - 2009 |
Keywords
- Fast Repetition Rate
- Symbiodinium
- Coral Reef Ecosystems
- Fluorescence
- Photon Flux-Density
- Photosystem II
- Marine-Phytoplankton
- Light absorption
- Photosynthetic pigments
- Community structure
- Pigments
- Symbiotic algae
- Fluorescence measurements
- Photochemical activity