Helping green sea turtles suffering with large debilitating tumors may be a simple as sunlight. Turtles with fibropapillomatosis are treated at rehab facilities where the tumors are surgically removed. Many do not survive or the tumors regrow. Researchers compared vitamin D levels in green sea turtles with and without evident tumors to see if sunlight exposure would influence vitamin D levels and other health parameters. Turtles receiving treatment were housed in tanks exposed to higher or lower levels of sunlight. Results showed that turtles exposed to greater sunlight showed greater increases in plasma vitamin D and a more successful recovery. Turtles kept in the sun tanks also experienced less regrowth of tumors compared to those exposed to low UV light conditions.