Light
Light is a central factor for symbiotic corals as it supports
the photosynthetic endosymbionts inhabiting the coral
and, therefore, contributes to maintaining both partners of
the symbiosis healthy. Although some corals can be facultatively symbiotic (Piniak 2002), most symbiotic corals need
appropriate light to stay in good condition and grow. Light
endorses the production of photosynthates by the photosynthetic endosymbionts and consequently their translocation to the cnidarian host (Muscatine et al. 1981; Bachar
et al.2007; Lealet al.2013b). This process largely contributes to coral calcification and growth (Falkowski et al.
1984; Wijgerdeet al.2012a). Light also affects coral quality-related aspects such as physiological condition, shape,
colour and metabolite content (Titlyanov & Titlyanova
2002; Todd 2008; Khalesiet al.2009). However, the selection of appropriate light conditions for high productivity
and high quality is often species-specific and it may be
ambiguous because a key feature of symbiotic corals is the
adaptation to different light environments (Titlyanov &
Titlyanova 2002).
Light manipulation inex situfacilities comprises quantitative (irradiance), qualitative (light spectrum) and technological aspects (types of light sources). Light quantity is
usually measured as quantum irradiance falling within the
range of photosynthetic active radiation (PAR). Light quality is characterized by its spectrum, which varies with depth
and light source (Masset al.2010; Rochaet al.2013a). The
main light sources used for coral culture are fluorescent
lamps, metal halide lamps and light-emitting diodes
(LEDs). Please consider other reviews for a more complete