top view of a steep drop-off at a coral reef at pangangan island, calape, bohol, philippines. shallow waters that suddenly drop

dropoff drops steep incline abyss thalassophobia contrast ocean sea shelf floor sudden change depth deep vivid blue turquoise calm prostone edge barrier coastal border copyspace copy space background periphery verge demarcation tropical tropics limit scuba snorkeling abyssal unfathomable bottomless pangangan island calape bohol philippines descent abrupt sheer vertical boundary coral reef zone atoll top view drop-off philippines shallow waters suddenly drop