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Publication year : 0
Thematic : Coral Reef
Language : English
Note
In this study, we used a correlative approach
to (1) test for an association between bleaching and host
tissue composition during a natural bleaching event,
and (2) assess whether bleaching susceptibility varies
between years. In August 1997, Montastraea franksi at
15-m depth on Conch Reef, Florida, bleached and the
severity of the response varied among individuals. Seventy-
five randomly selected colonies were quantified for
bleaching using both an ordinal scale, assigned by eye,
and a continuous scale, assessed using red, green, and
blue (RGB) spectral analysis of photographs. Zooxanthella
density and chlorophyll a content were evaluated
as measures of bleaching, and coral tissue was
analyzed for glycerol, free amino acids (FAA), protein,
and mycosporine-like amino acids (MAAs); collectively,
these are described as the ‘‘tissue composition.’’ In 1998,
most of the same coral colonies were analyzed for color
and zooxanthella density to determine whether colony
color in 1997 was correlated with color in 1998. In 1997,
colonies of M. franksi that were ranked by color differed
significantly in RGB brightness, zooxanthella density,
and chlorophyll a content, but not in tissue composition.
Similarly, a multivariate test for a linear relationship
between color and tissue composition did not reveal a
significant association. Analyses of corals in 1997 and
1998 revealed a significant positive relationship between
color in both years (i.e., the same colonies were similarly
colored in each year). These results are discussed in the
context of the temporal scale of the sampling regime, the
nature of the measured traits, and the adaptive bleaching
hypothesis.
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Keywords : Emballonura raffrayana
Encoded by : Pauline Carmel Joy Eje
