'Keystone species' and Environmental Problems

เนื้อเรื่อง

             Starfish and anemones were grouped into a Phylum Echinodermata. Scientists found out that starfish is not just an ordinarymarine animals, it is actually a  'keystone species', which has more role in balancing up other organisms, in the other word it is balancing up ecosystem. So if human or other animal removes or do anything to it, they are destroying the balance of the whole ecosystem. Still there are also the starfish called 'Crown of Thorns' starfish that is actually causing trouble for the ecosystem, human society and economic.

             Scientist is actually discovered that many white, dead coral reef and this event is not happen only in one place but actually it is a big problem that is happening around the world. Like the Great Barrier Reef, a place known as the world biggest scheme of coral reef and the coral here are also very old. But right now they have found out that there were lots of dead coral and it is because of the Crown of Thorns starfish. Crown of Thorns starfish obtain food by eating other organisms, including coral. It actually eats the tissue of a suitable coral, then coral would eventually became white, dead coral skeleton. Not only the Great Barrier Reef but also in Phuket, Thailand, the experts also discovered that there are Crown of Thorns starfish outbreak, they said that if there is 10 Crown of Thorns starfish in one hectare, it is considered as an outbreak area. But if there are 30 or more, that area is considered as a very serious outbreak. So many people especially those divers ask if they should kill those starfish or not. And the answer was they should kill it in a limit amount, in the other word, kill it until the amount is not considered as  an outbreak but scientist also suggested that they should not kill all of them because as it is a 'keystone species', if it is all removed, then the balance of the ecosystem would be demolished. Because Crown of Thorns starfish helped balancing the system by eating those coral that is fast growing coral, especially staghorn coral, to give a space for those slow growing coral. So if the amount of Crown of Thorns is not too much and not too little, then it benefits the environment.

            When there is too much of Crown of Thorns starfish not only the environment that has been affected but also human society because when the starfish eats coral's tissues and left only dead coral's skeleton, which has only a pure white. People that usually pay money just to look at its beauty closely by scuba diving or snorkeling diving may not come anymore; just because there is too many dead coral, which has nothing interesting. So people that were doing this kind of business recieve less income. Fisherman were also having trouble because this starfish has also eaten all the fish that fishermen were usually caught before, so their income became less and less.

          In reality, all the problem was caused by human because firstly fisherman has caught too many of Crown of Thorns starfish's predators. For example cowfish, Puffer fish and triton. People like to catch triton just because of its shell, which can be used for decoration. But they do not know they were destroying the balance of the ecosystem by letting the amount of Crown of Thorns starfish increasing. Secondly, chemical fertilizer that ws used in agriculture was released into the sea, making the plankton to grow much faster. As the plankton is a food of littke Crown of Thorns starfish, those little Crown of Thorns starfish has more chance to survive because there is lots of food for it. 

         So it is all come back to human. As human started, they have to help solve this problem. Firstly, they might want to satrt not to catch those predators of Crown of Thorns starfish or just decrease the amount of it little by little. Secondly, they might not want to throw away the chemical fertilizer into the sea. Thirdly, they might want to help remove the Crown of Thorns starfish, while doing that they should be careful not too kill too many of it. Otherwise they would just destroy the balance of the ecosystem again!