Light induced intraspecific variability in response to thermal stress in the hard coral Stylophora pistillata

Abstract

Recent research suggests that prior exposure of several months to elevated irradiance induces enhanced thermal tolerance in scleractinian corals. While this tolerance has been reported at the species level, individual coral colonies may react differently due to individual variability in thermal tolerance. As thermal anomalies are predicted to become common in the upcoming future, intraspecific variation may be key to the survival of coral populations. In order to study light-history based thermal stress responses on individual colonies, we developed a preliminary microcosm experiment where three randomly chosen, aquacultured colonies of the model coral Stylophora pistillata were exposed to two irradiance treatments (200 and 400 μmol photons m−2 s−1) for 31 days, followed by artificially induced heat stress (∼33.4 °C). We found different responses to occur at both the intraspecific and the intracolonial levels, as indicated by either equal, less severe, delayed, and/or even non-necrotic responses of corals previously exposed to the irradiance of 400 compared to 200 μmol photons m−2 s−1. In addition, all individual colonies revealed light-enhanced calcification. Finally, elevated irradiance resulted in a lower chlorophyll a concentration in one colony compared to the control treatment, and the same colony displayed more rapid bleaching compared to the other ones. Taken together, this study highlights the potential importance of intra-individual variability in physiological responses of scleractinian corals and provides recommendations for improving methodological designs for future studies.

The Effects of Temperature, Light, and Feeding on the Physiology of Pocillopora damicornis, Stylophora pistillata, and Turbinaria reniformis Corals

“…Much work has been carried out on the individual effects of increased temperature, light, and feeding on coral physiology (e.g., [20,47,48]), but only one has tested the multistressor effects of all three simultaneously [49]. This study found feeding and low light levels to mitigate the negative effects of elevated temperature on chlorophyll a concentrations and photosynthetic rates in Turbinaria reniformis and Stylophora pistillata.…”

Effective asexual reproduction of a widespread soft coral: comparative assessment of four different fragmentation methods

“…Out of the four assessed methods, the glue method, which works well for hard corals (see e.g ., Tilstra et al, 2017 ), demonstrated the lowest success rate. Only 1 out of 20 fragmented colonies attached to the coral plug, albeit on the side of the plug.…”

The Effects of Shade and Light on Corals in the Context of Coral Bleaching and Shading Technologies

“…Muir et al (2017) found species identity explained 33.2% of the variation in observed bleaching and identified species lineages of either high or low relative extinction risk. Tilstra et al (2017) demonstrated intra-individual variability in physiological responses of the scleratinian coral Stylophora pistillata, which may be attributed to differences amongst the spatially distinct clades for this coral species. Overall some genera are considered highly susceptible to bleaching stress, also shown among species variation (Muir et al, 2017).…”

“…Regardless of the shade source (natural or artificial), the reviewed literature demonstrates that different coral species may respond differently (i.e., interspecific, intraspecific and even intracolonial variations) to variable levels of light and stressors (Tilstra et al, 2017;Mizerek et al, 2018;Wangpraseurt et al, 2019;Kuanui et al, 2020;Dobson et al, 2021). Muir et al (2017) found species identity explained 33.2% of the variation in observed bleaching and identified species lineages of either high or low relative extinction risk.…”