While Walker found broken pieces to procure and store away, he noticed that there were clear spots that the snowflame corals had not grown at all. Since the snow flame coral would most likely not grow here and have monsters that ate it here, this was odd. It clearly looked like something had broken it to eat it.
Following this line of thinking, Walker wondered if more than just coral had been dormant here and struggling to grow in this unfamiliar area. The coral had already struggled due to the light mana being too dense and causing the water to heat and cool unnaturally.
Well, unnatural for the coral. For this location and the form that the islands took, it was somewhat natural.
His question was answered right after he began looking though.