Nine nature puzzle

The first puzzle; Tree leaves disappeared and vanished very quickly; Around, the Maar lake there are many trees and dense subtropical forest. All year round, lots of leaves fall into the lake with water, but no leaves would be found in the water or the bottom of the lake.
The second puzzle; No frog, no snake and no leech in the lake; In a big lake with an area of 2.3 square kilometers, there is no frog, no snakes and no leech, while lots of fish and shrimp are living.
The third puzzle: The wonder turtle and dragon fish; On 28th of May 1998, 60 generals from the National Defence University saw the dragon fish and the big turtle, 4 meters long, 2 meters wide respectively. A number of big fish and turtle have been found in the lake after that. It is said that the big turtle also saved a people in the lake. Therefore, the turtle and fish got the name of "wonder turtle ".
The fourth puzzle; Warm in winter and cold in summer; Surrounded by subtropical forest and basalt rocks, air in the lake is very fresh and there is area with 105688/cm3 of anion. Therefore the lake is called "Natural Oxygen Bar" and usually, temperature difference inside and outside the lake is about 3℃.
The fifth puzzle; Water level difference between water edge and center of the lake is about 30cm. Scientists found that water level at the center of the lake is 30cm lower than the water around the lake.
The sixth puzzle; Water in the lake has self-adjustment function. The lake gets neither dry nor flood. On the Mid-Autumn Festival Day in 1948, no raining for a long time, water in the lake suddenly flooded to the monk temple. Therefore, all the monks went the top of the mountain to escape the flood. Three days later, water came down to its original level.
The seventh puzzle; Water in the lake is good for health. Local people said that swimming in the lake would beauty the skin and cure skin diseases and cooking with lake water could release high blood pressure. As a result, local people should feed newly borne child with lake water as they believe that water from the lake would bring luck and prevent diseases as well.
The eighth puzzle; The carp's bone is hard and while bone of the Triapia Nilotica is soft; After moving to other fresh water area, bones of carps and Triapia Nilotica would be the same as other normal fresh water fish.
The ninth puzzle; Never feel tired when climbing in the subtropical forest; Climbing in the subtropical forest, people would feel that there is a magnetic force to push upwards.
Water Pines around the lake