Effects of future climate on coral-coral competition

in direct contact with O. faveolata exhibited significantly higher Fv/Fm than the “no-contact controls” on day 7, but by day 14, this pattern was no longer significant (Fig 4). As with the interaction between P. astreoides and M. cavernosa, lesion sizes of P. astreoides and O. faveolata were unaffected by temperature and OA (Fig 5). However, P. astreoides devel- oped discoloration areas indicative of lesion formation that were 4x larger than those of O. faveolata at day 7 (Fig 5A, p<0.001) although there were no significant differences in the por- tions of the coral with bare skeleton (Fig 5C, p = 0.45). By day 14, the overall size of the discol- oration area was no longer significantly different between the two coral species (Fig 5B, p = 0.070). However, the area with complete loss of coral tissue was 133% larger on P. astreoides than O. faveolata (Fig 5D, p = 0.048). Fig 3. Effects of climate and coral-coral competition on endosymbiont photosynthetic efficiency (Fv/Fm). Maximum quantum yield values (means ± SE) for (A) Porites astreoides in contact with Orbicella faveolata at the location of direct contact (Contact Location) vs. 3 cm away from area of direct contact (No Contact Location) at day 7, (B) O. faveolata in contact with P. astreoides at the Contact Location vs. No Contact Location at day 7, (C) P. astreoides in contact with O. faveolata at the Contact Location vs. No Contact Location at day 14, and (D) O. faveolata in contact with P. astreoides at the Contact Location vs. No Contact Location at day

14. Analyzed with two-way ANOVAs comparing contact area and climate condition. Dots represent individual data points. The p- value contrasting values between “Contact Location” and “No Contact Location” under future conditions is from one-way ANOVA N = 6. https://doi.org/10.1371/journal.pone.0235465.g003 PLOS ONE Climate change alters coral-coral competition PLOS ONE | https://doi.org/10.1371/journal.pone.0235465 August 13, 2020 8 / 16