Photobiology of Symbiodiniaceae hosted on Siderastrea stellata in the southwestern Atlantic

The health of the coral species Siderastrea stellata was investigated as an indicator of climate changes impacts at the Fernando de Noronha Marine National Park, southwestern Atlantic Ocean. Chlorophyll a maximum quantum yield and Rapid Light Curves (RLCs) were produced using a red-light pulse amplitude modulated fluorometer, Mini-PAM in S. stellata colonies. We collected genetic material from the same colonies in order to identify Symbiodineaceae hosted in each of them, considering that the colonies showed very different pigmentations between them. Our findings showed that colonies with pink pigmentation may be associated with higher temperatures, while indicating a high saturation point (Ek) and consequent greater efficiency in the dissipation of radiant energy. Our genetic analysis also demonstrated a high fidelity in association with Cladocopium spp. predominantly. Despite this, we hypothesized that this association may be the result of changes in populations of Breviolum spp. due to stressful events.