Adaptive variation in coral geometry and the optimization of internal colony light climates

Anthony, K. R. N., Hoogenboom, M. O. and Connolly, S. R. (2005) Adaptive variation in coral geometry and the optimization of internal colony light climates. Functional Ecology, 19 1: 17-26. doi:10.1111/j.0269-8463.2005.00925.x

Author Anthony, K. R. N.
Hoogenboom, M. O.
Connolly, S. R.
Title Adaptive variation in coral geometry and the optimization of internal colony light climates
Journal name Functional Ecology   Check publisher's open access policy
ISSN 0269-8463; 0269-2183; 1365-2435
Publication date 2005-02
Sub-type Article (original research)
DOI 10.1111/j.0269-8463.2005.00925.x
Volume 19
Issue 1
Start page 17
End page 26
Total pages 10
Place of publication Oxford
Publisher Blackwell Publishing Ltd
Language eng
Abstract 1. The ability of photosynthetic organisms to adjust their light climate has high adaptive significance because irradiance can vary spatially by orders of magnitude. Using a plating (foliaceous) coral species (Turbinaria mesenterina), we tested the hypothesis that plasticity of colony geometry optimizes internal irradiance distributions. 2. We developed a two-dimensional model to predict the internal irradiance distribution of a foliaceous colony as a function of its geometry. Field tests showed that the model explained 85% of the variation in irradiance within colonies of T. mesenterina with minimal bias. 3. Colony plate angle, plate spacing and range of tissue distributions into the colony were exponential functions of water depth. In shallow water plates tended to be nearly vertical, narrowly spaced, and had living tissue only near the growing edge of the plate. In deep water plates grew more horizontally, were more widely spaced, and had living tissue extending well into the colony interior. This pattern of phenotypic plasticity effectively evens out differences in within-colony irradiances. 4. We compared within-colony irradiance distributions across light habitats (depth), based on the observed variation in colony geometry with water depth. Despite fourfold differences in environmental irradiance, within-colony irradiances had a common mode of 100-200 mu mol m(-2) s(-1). This is near the hypothesized photosynthetic optimum defined by the upper limit of the subsaturation parameter (E-k) of the photosynthesis-irradiance curve. 5. Our study demonstrates that phenotypic plasticity of colony geometry is an important mechanism for regulating light capture during growth in T. mesenterina, and facilitates near-optimal internal irradiances across a wide range of environmental light regimes.
Keyword Ecology
mathematical model
phenotypic plasticity
photosynthetic optimum
scleractinian coral
Turbinaria mesenterina
Reef-building Corals
Measured In-situ
Phenotypic Plasticity
Water Motion
Carbon Gain
Q-Index Code C1

Document type: Journal Article
Sub-type: Article (original research)
Collections: Excellence in Research Australia (ERA) - Collection
Centre for Marine Studies Publications
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Citation counts: TR Web of Science Citation Count  Cited 38 times in Thomson Reuters Web of Science Article | Citations
Scopus Citation Count Cited 36 times in Scopus Article | Citations
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Created: Wed, 19 Sep 2007, 19:00:08 EST