Certain physical factors may increase resistance to bleaching caused by high sea surface temperatures (SSTs):
Cooling: Oceanographic conditions that cause mixing of heated surface waters with cooler deeper water can reduce temperature stress.
Shading: High island shadow or overhanging vegetation may reduce the harmful effects of sunlight.
Screening: Naturally occurring suspended or dissolved matter reduces sunlight penetration and may reduce bleaching.
Stress Tolerance: Coral communities that are exposed to extreme conditions regularly are often populated by species with a high tolerance for stress. Others do not survive.
Conditions only become stressful outside of normal ranges tolerated by the species at its location change.
Physical Factors (1:05)
Jamie Oliver discusses physical factors that may reduce the impact of rising sea temperatures.
A coral at higher latitudes, for example, may be acclimatized to much lower water temperatures than the same coral species at the equator. A rise above its normal temperature threshold would cause bleaching at temperatures easily enough to cause bleaching when they deviate significantly from those tolerated by the same species at the equator.