Red Light Represses the Photophysiology of the Scleractinian Coral Stylophora pistillata

Abstract

Light spectrum plays a key role in the biology of symbiotic corals, with blue light resulting in higher coral growth, zooxanthellae density, chlorophyll a content and photosynthesis rates as compared to red light. However, it is still unclear whether these physiological processes are blue-enhanced or red-repressed. This study investigated the individual and combined effects of blue and red light on the health, zooxanthellae density, photophysiology and colouration of the scleractinian coral Stylophora pistillata over 6 weeks. Coral fragments were exposed to blue, red, and combined 50/50% blue red light, at two irradiance levels (128 and 256 μmol m−2 s−1). Light spectrum affected the health/survival, zooxanthellae density, and NDVI (a proxy for chlorophyll a content) of S. pistillata. Blue light resulted in highest survival rates, whereas red light resulted in low survival at 256 μmol m−2 s−1. Blue light also resulted in higher zooxanthellae densities compared to red light at 256 μmol m−2 s−1, and a higher NDVI compared to red and combined blue red light. Overall, our results suggest that red light negatively affects the health, survival, symbiont density and NDVI of S. pistillata, with a dominance of red over blue light for NDVI.

Characterization of Available Light for Seagrass and Patch Reef Productivity in Sugarloaf Key, Lower Florida Keys

“…Controlled laboratory studies have shown that captive corals subjected to shorter wavelengths in the~blue region (~400 to~500 nm) have high growth and photosynthesis rates [28,29]. As previously mentioned, we found relatively high values of total absorption (ap + ag) in the water column at shorter wavelengths (~400 to~500 nm) for our study sites, resulting in lower light levels at these wavelengths reaching the coral community.…”

Trade-Offs Associated with Photoprotective Green Fluorescent Protein Expression as Potential Drivers of Balancing Selection for Color Polymorphism in Reef Corals

“…In agreement with a wavelength-dependent screening function of the CFPs, both morphs displayed comparably intense signs of light stress when they were illuminated with orange light outside of the spectral window covered by the protective host pigment. Orange-red light has been shown to negatively affect the photophysiology of Symbiodinium in coral tissues (Smith et al, 2013;Wijgerde et al, 2014). The comparable susceptibility of the two morphs to photodamage in this spectral range supports the conclusion that higher resilience of the HF morph under blue light stress is due to the screening by the CFP rather than by other photoprotective mechanisms that might be more dominant in this morph.…”

“…The capacity of the CFPs to exert a photoprotective function by selective screening of symbionts in the blue spectral range was assessed by exposing the corals to either blue or orange-red light. Orange-red light was chosen for the control treatment as it is not absorbed by the CFPs and should therefore negatively affect both the high and low fluorescent morphs due to the detrimental effect of this waveband on algal photosynthesis (Smith et al, 2013;Wijgerde et al, 2014).…”

Effect of LEDs Light Spectrum on Success of Fragmentation and Growth of Leather Coral <i>Sarcophyton</i> spp.

“…fragments. The utilization of light with specific wavelengths spectra, is to date poorly studded, however the few studies existing are contradictory Wijgerde et al (2014), when using illuminations of white, blue and red spectrum found a negative response on the coral Stylophorapistillata, showed an negative response of coral fragments exposed to red light and a positive response in blue light. However, Kinzie and Hunter (1987) found no differences in Montiporaverrucosa response when fragments were exposed to different lighting, white and blue.…”