Dear Dr. Jiang,
your article is of considerable interest. However, based on the referee's comments and your answers, the manuscript still has to undergo some substantial revisions. In light of these comments, we cannot accept the manuscript for publication yet, but would be very interested in considering a revised version that addresses the reviewers concerns.
Sincerely,
Christine Klaas

Dear authors,
Based on the comments of previous reviewers and the answer and the changes to the manuscript I would recommend publication after attending to the following:
- The organization of material and methods section makes it still somewhat difficult to understand which batches where used for which measurement. I would recommend transferring section 2.4 on settlement essays to the end of Materials and Methods (but before section 2.7 on data analyses) as it seems that these essays were carried out separately from the rest of the manipulations. Also, please be more specific on how petri dishes were incubated (as requested by one reviewer) in sections 2.2 and 2.4: were the dishes covered? Were they completely submerged or floating in the incubation tanks?
- It is my understanding that the manipulations described in sections 2.5 and 2.6 were carried out on the "recruits", hence these sections should be placed after section 2.3. (unless the measurements were carried out on the batches for settlement essays in which case they should be moved after the description of settlement essays).
- Similarly, do the results presented in section 3.1 refer only to the settlement essays? Please specify (maybe adding an sentence at the beginning of the 1st paragraph: "During the settlement essays larval mortality was only observed...").
- Figure 2: How many individuals (n=?) were measured for each treatment? This info could be given in the figure or figure legend.
- Table S3: what do the authors mean by "subject" does it actually correspond to treatment? As in "within treatments" and "between treatments".
- Figure 3: How many individuals (n=?) were measured for each treatment? This info could be given in the figure or in the figure legend.
- Figure 4: How many individuals (n=?) were measured for each treatment? This info could be given in the figure or figure legend.
- Section 3.3 p 14-15 lines 298-305 (2cnd paragraph): the references to the Tables should be corrected (Table S7 and S8 don't exist and Table S6 only contains information on calcification, I imagine the authors refer to Table S5?).
- Section 3.3 Line 307: Can the author provide the info on the numbers of recruits? 97% and 86% survivors out of how many?

Minor comments:
p. 3 line 63-64: remove "on coral reef" and striking".
p. 4 line 73: replace "of equivalent..." with "at equivalent..."
p. 4 line 83: replace "is more suite to the fluctuating than to the constant temperatures..." with "is more adapted to fluctuating temperatures..."
p. 4 lines 85-87: replace "Conversely, evidence for the deleterious effects of diel temperature fluctuations includes the significant reductions in photochemical efficiency, symbiont density and aerobic respiration in corals exposed to fluctuating temperatures compared to those inconstant temperatures..." with "Conversely, a significant reductions in photochemical efficiency, symbiont density and aerobic respiration were found in corals exposed to fluctuating temperatures..."
p. 5 line 110: replace "free-swimming and zooxanthellate..." with free-swimming zooxanthellate..."
p. 6 line 126: replace "the diurnal range during summer..." with " The diurnal range in temperature variation during summer..."
p. 6 line 128: replace "temperature began to increase around..." with "temperatures began to rise at around..."
p. 7 section 2.2: reorganize as follows "Eight P. damicornis colonies were collected at a depth of 3 m on 20 August 2015. Colonies were transported to Tropical Marine Biological Research Station, and placed 133 individually into 20 L flow-through tanks at ambient temperature (28.7  _0.5°C) under partially shaded light conditions (noon irradiance, ~300 μmol photons m2 s1). The outflow of each tank was passed through a cup fitted with a 180 μm mesh-size net to trap larvae. Larvae were collected at 07:00 on 22 August 2015, pooled and randomly assigned to the following two experiments: 1) To test the effects of temperature treatments on the photo-physiology, bleaching, calcification and growth of recruits, larvae were transferred to 10-cm-diameter petri dishes which were left floating in a flow-through tank. Twenty hours later, 4 dishes with a total of 35–40 newly settled recruits were assigned to each one of the tanks with the four experimental temperature regimes, respectively. Only recruits that settled individually and at least 1 cm apart from others were selected for the experiment in order to avoid possible contact between recruits during growth. Dishes were rotated daily to avoid the potential positional effects within each tank. 2) For the settlement assays, larvae were transferred to 5.5-cm diameter plastic petri dishes as described in Section 2.6."

p. 7-8, section 2.2, 1st paragraph: reorganize as follows:
'The two temperature regimes, constant and fluctuating, were set for the target temperature levels of 29°C and 31°C each. The late temperature value was 2°C above the ambient and 1 °C above the bleaching threshold for coral communities on Luhuitou reef (30 °C, Li et al., 2012), and within the range of projected increases (Bopp et al., 2013).
The pattern and range of temperatures in the two fluctuating treatments were based on in situ records obtained during larval release of P. damicornis (Fig. S1d), and the assumption that the predicted 2 °C increase in mean temperature would entail a 2 °C shift over the whole daily temperature cycle (Burroughs, 2007). The 29 °C treatment, corresponding to the ambient temperature at the collection site of adult P. damicornis, was used as the control treatment. "
p. 8 line 160: replace with "All incubations were carried out in four 40L tanks..."
p. 8, line 162: replace with "Temperature regimes were set using..."
p. 9, line 184-189: replace with "The settlement essays were conducted in 5.5-cm-diameter petri dishes on 22 August 2015 and starting at around 09:00."
p. 12 line 241: replace with " reactions often double with a 10°C rise in temperature."
p. 15 lines 300-305: reorganize as follows:
"The effects of temperature fluctuations on calcification depended on the mean temperature (Fig. 4d), even though the interaction between temperature level and regime was not statistically significant (Table S6.): at 29 °C, the fluctuating regime had no discernible effect on calcification, while in the fluctuating regime with a mean temperature of 31 °C a significant reduction (20%) in calcification was observed when compared to the constant 31°C regime (Table S7.)."
p. 19 line 389: I am not sure what the meaning of "loner" in this sentence is. Do the authors mean "single" or "longer"?
p. 20 line 420: replace with "Clearly, thermal tolerance of corals depends on the ambient..."
p. 22 line 458: replace with: "...by a parabola with an optimum..."
p. 22 line 468: replace with: "First, during the warmest part...."
p. 24 lines 507-508: replace with "Therefore, corals in highly fluctuating environments may have the potential..."