Physical Factors
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 such as screening or shading can increase the resitance to bleaching caused by increased sea surface temperatures. Photo © Bruce Carlson
Video
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.