How far can sunlight penetrate into the ocean?
Significant sunlight can only penetrate 100 meters freely. Because seawater is relatively transparent, about 5% of sunlight penetrates to a depth of 262 feet (80 meters). However, if the water contains significant amounts of silt, algae or other factors, the penetration depth can be reduced to 164 feet (50 meters) or less. Learn more about the ocean light zone.