What is the passage mainly about? [Passage: The sea turtle has been a species at high risk of extinction for many years. In Taiwan, Xiaoliuqiu (also called Little Liuqiu or Liuqiu), an island belonging to Pingtung County in Taiwan has a high number of sea turtles, and the majority of the residents there have been aware of the importance of protecting sea turtles. However, the island has so many tourist attractions that many visitors come to the island on weekends and holidays. They come for scuba diving, SUP (stand-up paddling), snorkeling, and so on. Although these activities promote local economic growth, it leads to some influences on marine life and the environment. To decrease the burden on the environment, a team of volunteers, consisting of university students in Taiwan, non-profit organizations, and residents have started to conduct a project about environmental protection, including sea turtle conservation and marine-debris decoration. The team observes the life of sea turtles, keeping records of their migration behaviors. The team also has a sea turtle patrol at night from 7:00 p.m. to 5:00 a.m., learning about how sea turtles lay their eggs. On the other hand, the team conducts beach clean-ups every day. The volunteers collect marine debris to create an art wall near the beach. This decoration wall aims to remind visitors that they should reduce pollution and disturbance. The head of the team says the volunteers will take more actions to keep the island green.]