euphotic euphotic euphotic the answer euphotic euphotic all photic traces cease by 1000 meters euphotic http://oceanservice.noaa.gov/facts/light_travel.html 200m deep euphotic http://oceanservice.noaa.gov/facts/light_travel.html euphotic http://oceanservice.noaa.gov/facts/light_travel.html http://oceanservice.noaa.gov/facts/light_travel.html Light http://oceanservice.noaa.gov/facts/light_travel.html euphotic euphotic