increase beyond 200 lmol quanta m
2
s
1
(personal
observation). In addition to changes in chlorophyll content,
coral colour can change due to changes in the levels of
other pigments and proteins present in the symbionts and/
or in the coral tissue (Lealet al. 2014a). Such proteins,
commonly referred to as fluorescent proteins, are usually
defined by their excitation and emission spectra and display
very different and attractive colours. A study by D’Angelo
et al. (2008) showed that colonies illuminated with low
light intensities appeared brownish, whereas those growing
under moderate light displayed distinctive colorations, such
as blue, green and red. The increase in pigmentation of
moderate light-treated specimens was striking when the
fluorescent proteins in coral’s tissue were excited by blue or
green light. It has been suggested that these proteins have a
photoprotective role, as well as other host pigments that
are responsible for the intense bluish, green or reddish hues
(Salihet al.2000; D’Angeloet al.2008). Coral exposure to
high light intensity produced a more intense green fluorescence inAcropora nobilisand increased pigmentation in a
pink morph ofPocillopora damicornis(Takabayashi & Hoegh-Guldberg 1995; D’Angeloet al.2008). Besides responding to light fluctuations, fluorescent proteins can also be
produced in response to other types of stress, such as
increased temperature, breakage, fish bites, predation and
disease (Bandaranayake 2006; Matz et al. 2006; Palmer
et al.2009).