culture of china

The Qiang nationality is one of the oldest ethnic minorities in China. They mainly live in the upper reaches of the Minjiang River. Sichuan Province. Located 2.000 meters above sea level are several picturesque lakes. One day in July 2001. news came that a disaster was coming. The news frightened all the villagers. They came to the lakes and prayed. What had happened there?

Baishi Lake covers an area of eight square kilometers. It lies in Songping village. Diexi town. Maoxian county. It��s 90 kilometers away from Maoxian county. In the mountains surrounding Baishi Lake. there are more than ten villages of the Qiang nationality. July 10th was an important Qiang festival and everyone gathered on the banks of Baishi Lake to celebrate. However. a strange event at the lake turned the celebration into a disaster.

At nine a.m.. July 12. 2001. when Pan Zhicheng. deputy director of the Bureau of Songping Administration. was walking around Baishi Lake. he saw red streaks of water in the lake. which looked like blood.

Pan Zhicheng observed the water along the lake. He found that red streaks of water increased gradually and spread out. After 10 a.m.. the red streaks of water covered the entire lake.

Were ancient spirits showing something to the villagers through the red lake water and strange fish? Some villagers thought the Baishi God was showing his power. Some others thought a sea horse had come to life. However. all these assumptions had the same outcome: an earthquake was coming.

Next to Baishi Lake is a huge white rock. Since the Qiang have always revered white rock. they call the rock. White Rock God. and view it as a treasure that can conquer the lake. In order to avoid the coming disaster. villagers ran to the lake and prayed to the White Rock God.

Why were the villagers so fearful of earthquakes? Because Diexi has experienced several earthquakes. According to records. at 3:50 p.m. on August 25. 1933. a 7.5 earthquake shook Diexi. Mountains collapsed and huge rocks fell down like rain. The entire town sank 70 meters and was buried under rocks along with the ten neighboring Qiang villages. The old Diexi town was leveled to the ground.

Li Mingxiao is 92 years old. She fortunately survived the earthquake. She is still very feared when she talks about the earthquake.

The ruins witnessed the prosperity as well as the destruction of the old town. The disaster made a strong impression on the locals. The earthquake has placed a shadow over them.

The earthquake also cut the Minjiang River into several segments. which formed more than ten seismic barrier lakes. Baishi Lake is one of the barrier lakes.

In 2001. earthquakes were frequent in China. From January to July. there were over six earthquakes with a magnitude over 5.0. The strange phenomenon of Baishi Lake attracted the increased attention of the local government. Soon. experts from the State Seismological Bureau and Sichuan Seismological Bureau surveyed the land.

Zhu Ziqiang. State Seismological Bureau

We had never seen such a phenomenon. It was rare in history for the entire lake to turn red. Instinctively. we thought it was a warning sign for an earthquake.

Experts carried out a hydrologic survey of Baishi Lake. They found the water was clear at the water mouth and there was a clear division between clear water and red water.

Before an earthquake. due to the earth��s movement. well water and lake water may become muddy or change color. There are two possibilities. One is water turns white. such as a milky or yellowish white. which is caused by the overflow of calcium in the rock stratum. The other is the water turns red. which is caused by the overflow of ferromanganese in the rock stratum. Experts found red water spread from the center of the lake to the four sides. which was likely to be the result of plate movement. If this was true. an earthquake was unavoidable.

After careful observation. experts found another strange phenomenon: the lake water was not red all the time. In the morning. the water was clear. As the temperature went up. it became redder. In the afternoon. the lake water became clear again. What��s more. even at noon. not all the lake water turned red but only the shallow water was red.

Only the surface was red. It was estimated to be 30cm to 50 cm deep. When we stirred the surface with a stick. we could see the water below was clear.

Experts were puzzled because the red water didn��t spread from a certain point to the four sides. It kept changing along with changes in the environment such as currents and wind force. which differed from regular warning signs of an earthquake.

Let��s assume this is a model of Baishi Lake. Before an earthquake comes. the lake water turns red. It is usually because of a red substance overflowing in the rock stratum. What��s more. when the lake water turns red. it is impossible for it to clear up quickly and change along with sunlight and temperature. In fact. lake water turning white or red is a common warning sign for an earthquake. but it is not a decisive or the only basis to judge if an earthquake is coming. We shouldn��t solely depend on warning signs. but use seismological instruments to observe and study the warning signs that reflect the movement of the earth��s crust. In the earth��s crust. there are chemicals and gases that can reflect the movement of rock stratum. for example. radon. It is a radioactive element as well as a rare gas. When the earth��s crust is pressed and squeezed. it easily passes over the cracks of the rift belt. Therefore. if the content of radon in an area increases suddenly. an earthquake is likely to occur. The local seismological station usually does the testing. What did the experts learn from the local seismological station?

The well is 472 meters deep. We test the content of radon here. Radon exists deep under the ground. It��s sensitive to physical changes. It was considered a warning sign of earthquakes. According to our present test. the content of radon is normal and it doesn��t show any unusual pattern.

In the monitoring data. experts didn��t find anything that showed unusual movement of the earth��s crust. The local geological structure was stable and rock stratum was not likely to move haphazardly. Why did Baishi Lake turn red? Did it have something to do with the chemical substances in rock stratum? Experts found that the local rocks were mainly dark grey schist. which became carbon black after weathered. Even if the rock stratum moves frequently. it��s difficult for lake water to turn red. In order to discover the truth. experts sampled and tested the lake water at different levels. They found the content of organic substances in the lake were very high but they didn��t find any chemical substance that reflected the irregular movement of the earth��s crust.

The water turning red wasn��t because of chemical elements in the rock stratum but from a microbe on the surface of the water.

The answer is clear. Baishi Lake turned red because a kind of red microbe in the water propagated in a large amount. Why did a large amount of fish gather at the mouth of the lake? Experts said it was because the red microbe consumed large amounts of oxygen in the water.

The possibility of earthquake was removed. but the local people still felt worried.

Can the mysterious microbe secrete poison to pollute the water? In order to clear up doubts quickly. experts tested the water in Baishi Lake immediately.

Experts studied what happened in Baishi Lake and thought the phenomenon was rare in lakes. What is this red microbe? From the water quality and environment of Baishi Lake. experts thought the red microbe was possibly Haematococcus pluvlalls.

Haematococcus pluvlalls is a single celled algae. In its cell is red pigment called astaxanthin. which is similar to carotene. Since astaxanthin can prevent cancer. some developed countries have started mass production of it. If the microbe is Haematococcus pluvlalls. it��s definitely good news for people in Diqxi.

However. through further observation. experts found the microbe moves very quickly unlike Haematococcus pluvlalls. which doesn��t move fast.

Liu Yongding. Researcher ��Institute of Hydrobiology. Chinese Academy of Sciences��

If it isn��t Haematococcus pluvlalls. then what is it? Experts condensed the observation liquid and lowered its speed. Under the high-power microscope. the mysterious microbe that once caused panic showed its true features. Its cell nucleus is purplish red and it has a tail.

Liu Yongding:

It is not Haematococcus pluvialis. It is another algae. It��s a dinoflagellate. It is calleIt looks like an egg. In the middle. there is channel. It��s a prominent feature

and totally different from Haematococcus pluvlalls.

What you see on the big screen is dinoflagellate under a microscope of one hundred magnification. Dinoflagellate is a special living creature. It has the characteristics of both animals and plants. Botanists consider it as a photosynthetic plant. It has chlorophyll. It can undergo photosynthesis and turn inorganic carbon into organic nutrition. However. it has flagellum. which is like a tail under a microscope. It can feel the stimulus of the surrounding environment and swim freely. Therefore. zoologists look on it as an animal. Since dinoflagellate has the special characteristics. it will gather on the surface of lake when sunlight is ample. When it takes in enough nutrition. it will swim swiftly back to the lake. In general. the mass propagation of microbes is related to local environmental pollution that causes the water to be rich in nutrients. Yet. it is hard for us to associate the beautiful scenery of Baishi Lake with environmental pollution. Why did dinoflagellate propagate in Baishi Lake?

Experts thought the natural environment around Baishi Lake was the main reason for the mass explosion of dinoflagellate. The forest is extraordinarily dense. In autumn. deadwood and leaves fall into the lake. Year after year. the deadwood and leaves rot and the nutrition in the lake increase. which provides a good basis for the propagation of dinoflagellate. However. why did dinoflagellate only appear in 2001 and 2004? Experts were confused. Through further observation. they found in 2001 and 2004. the climate in the area shared similar features. In Maoxian County. it was dry and short of rain. which was rare in history. The water level of lakes decreased quickly and the current slowed. Experts thought because of this. the water temperature rose and the density of nutrition increased. which provided dinoflagellate a good environment.

Protein is the most important norm of water quality. The water is now rich in nutrition and the water quality has changed. In the course. plankton grows and increases quickly. The variety of plankton also increases. The change of water color reflects the change of water quality.

The mysteries of Baishi Lake have been cleared up. Local people are no longer afraid of the lake water. What��s more. they make use of the strange phenomenon to attract tourists. However. experts have warned that dinoflagellate is very sensitive and it will appear frequently when the environment is right. If dinoflagellate over propagates. it will affect the growth of other living creatures in the lake and seriously damage the food chain in the lake.