Although I understand why the authors did not want to provide the exact locations of theirs surveys, I think they could specify in which other areas of the atoll they also explored without providing their exact locations. Did they include other areas around Dongsha Island, arears in patchy reefs in the lagoon in proximity with other seagrass bed areas or even on the reef flat?
I am a bit surprised of the way the authors have expressed the depth. It is more typical to say something like "X meters relative to the mean sea level".
Please specify that Syringodium isoetifolium is a seagrass species.
I think the authors of the citations should be provided before each number in the following sentence: "Additionally, while reported only encrusting N. kamurai from Okinawa, reported on occasional laminar growth of N. cf. kamurai."
In order to avoir repetition, replace "known" by "recorded up-to-date" or by another synonym in the following sentence: "The population of Nanipora at Dongsha Atoll represents by far the largest known population of this relatively unknown genus."
Replace "studied" by "investigated" in the following sentence: "The ecology of Nanipora remains to be studied, and future studies should therefore examine not only coral reefs, but also seagrass beds."
For accuracy, I would recommend to add a sentence with the appropriate citation, which states that Dongsha Atoll is a Marine Protected Area, albeit some illegal fishing are still occurring (as the authors wrote down).
The authors may also want to emphasize that Dongsha Atoll has alreedy lost many seagrass bed areas (especially on the reef flat) and potentially some undiscovered colonies of Nanipora could have also been lost. Like the authors mentioned, understanding the ecology of Nanipora is therefore a very critical topic that should be tackled very quickly.