The lake is actually a breakwater made of frozen fish? The shocking "dead fish lake"!

Editor’s Note:

Scientific expedition travel notes refer to articles or books written by researchers or explorers who go to a certain area for scientific investigation or exploration and record what they see, hear and feel. This article was published on the China Science Popularization Expo website in March 2014 by Wu Yuhu, a researcher at the Northwest Plateau Institute of Biology, Chinese Academy of Sciences. It is still thrilling and exciting to read today, and it feels like you are actually there.

Part 1

The Origin of the “Dead Fish Lake”

After leaving the Zhalinghu Township Government, we braved the biting cold wind and heavy snow and came to the small lake near Cuo Ri Gaze to set up camp. For more than a month, we rode horses to visit tents, ate and lived with local Tibetan herdsmen, and "enjoyed" the cold of early spring on the plateau together. The temperature has gradually risen in the past half month, but there are still unavoidable sudden cold attacks.

The surface of Eling Lake in front of the tent was still an endless world of ice and snow. Only the 20-30-meter-wide ice on the northwest side of the lake had melted. The early-arriving waterfowl were already swimming on the water. The ice on the small lake behind me no longer existed.

We approached the lake and were surprised to find a 5-10 meter wide dead fish belt on the north, east and south shores of the lake. The three shores of the lake were all made of densely piled frozen fish, mixed with ice blocks of varying sizes. It was like a breakwater made of frozen fish. Some fish scattered far away had been dried by the wind, but most of the concentrated ones were hard frozen fresh fish with ice. A section of about 5-10 meters long could fill a large truck. We rode on horseback to inspect it. The accumulated fish belt was about one kilometer long. You can imagine how many tons of fish were wasted here.

Although humans are not lucky enough to enjoy so many fish, the water birds here enjoy the fruits of their labor. Thousands of brown-headed gulls and other water birds are happily noisy, flying up to block out the sun and falling down to a grayish white, enjoying these heaven-sent delicacies to their heart's content.

According to our observations at the lake, the cause of this situation was undoubtedly the wind. The melted ice in the small lake formed large and small pieces floating on the water, and then was blown to the lake by the strong wind. As the ice blocks were constantly crowded near the east bank, they moved sideways or turned over, and because the lake was shallow, the fish in the lake were pushed onto the beach in the process. This is another example of the ruthless consequences of the power of nature. From then on, many county and township officials in Maduo County got used to calling this small lake "Dead Fish Lake". In the grassland construction plan map of Maduo County that I drew later, this unknown small lake was simply named "Dead Fish Lake" to echo everyone's habit.

I spent an unforgettable night by the dead fish lake. When I woke up in the morning, I looked at Eling Lake again. The lake surface was covered with ice and white yesterday, but it was covered with blue water overnight. The changes of this plateau lake are amazing.

It turns out that since the Eling Lake is a lake where the Yellow River flows, although the lake surface is frozen three feet, the water under the lake is still flowing. When the temperature rises, the ice on the lake surface begins to melt from the bottom. Although the ice layer on the lake surface seen yesterday is still connected, it is already very thin, and most of the ice layer is connected to and separated from the water surface. If one part collapses, the whole line will naturally collapse.

Part 2

Bathing Thunderstorm Area

As the investigation continued, we came to the Huanghe Township of Maduo County. There is a high mountain meadow on the bank of the Requ River in Huanghe Township. Every summer, the meadow dotted with colorful alpine flowers covers the mountains and ridges like a green carpet and stretches to the horizon. The clear river flows slowly around it. Herds of cattle and sheep are scattered on this plateau pasture with lush grass and water, presenting a peaceful and happy pastoral scene. Riding a yak to investigate in such a beautiful scenery is like a wild crane cruising in a painting, which can make people forget everything else and feel happy.

However, just as we were enjoying all this, a cool breeze suddenly blew by, and a dark cloud came from nowhere, gathering more and more, followed by lightning and thunder, and then a downpour. We could only accept the shower of water from heaven.

The human instinct of self-protection and my long experience of living in the wild have made me subconsciously develop a strong sense of self-protection every time I encounter such a situation. Then, I will use the relevant knowledge I have mastered to exert my greatest self-protection ability in a timely manner and quickly take corresponding self-protection measures. This ability is indeed indispensable for survival in the wild.

To prevent lightning strikes, Mr. Chen Jiamu from the Maduo County Veterinary Station and I had already jumped off the yak's back. We first folded the bayonet of the automatic rifle behind us and put it on our backs to prevent lightning. Then we led the yak to a nearby earthen ridge and squatted down, keeping a distance from the yak and letting the heavy rain pour down on us.

Why can't we use the huge body of yaks to block the wind and rain? Because scientific knowledge tells us that when a thunderstorm comes, people in the wild should try to find a low-lying place to take shelter temporarily, in order to prevent objects protruding from the ground, such as trees, from attracting lightning. At this time, not only can we not take shelter under a big tree, but we must also prevent the harm of "step voltage". The so-called step voltage is that when lightning strikes a certain place on the ground, a potential field that gradually decreases from the center to the surroundings will be formed within a certain range around the place. People and animals will be injured or killed within this range due to the potential difference between the two legs. Therefore, when thunder and lightning roar, people in the wild should not run too much, but should stand with their legs together or squat in a hidden place that is as dry as possible to prevent step voltage. However, the yaks we rode ignored these scientific principles and still stood there with their four hooves spread out, as if nothing had happened. They really had a posture of being ready to die, and we had to "stay away from them".

The weather in the source of the Yellow River in summer is as unpredictable as that in all plateau areas. Often, the sky is clear and suddenly overcast, thunder and lightning strike, and heavy rain pours down. But when people are still in a panic and have not yet settled down, the wind, rain, thunder and lightning will disappear in an instant, and the sun will show a hot smile again. And when you are thankful that the "clouds have disappeared", there may be a sudden burst of snow grains that are neither snow nor hail, hitting you on the head and making you dizzy. During the investigation of the source area of ​​the Yellow River, we have become accustomed to such encounters. Sometimes we encounter them several times a day. The clothes are soaked, dry and wet, wet and dry again.

However, this area is different from other areas. I have heard that this is a thunderstorm-prone area. Thunder and lightning accompanied by heavy rain often continue to rumble and flash for a long time. In the past, cattle and sheep have been killed, and people have also suffered. Not only that, some people even said that they saw the top of the high-standing tent "sparking fire" during a thunderstorm. Although I have not seen it with my own eyes, I know that this is a tip discharge phenomenon during a thunderstorm.

In thunderstorm weather, the ground atmospheric electric field can reach tens of thousands of volts per centimeter. When the atmospheric electric field exceeds 800 volts per centimeter, various pointed objects on the ground, such as flowers, branches, crops and buildings, will produce tip discharge. When the electric field exceeds 10,000 volts per centimeter, a dim blue light will be emitted near the tip. This phenomenon is called "Elmore Fire", also known as the "corona" phenomenon.

People sailing on the ocean sometimes see fire near the mast of a ship. Mountaineers encountering thunderstorms sometimes suddenly find their hair "burning", and sparks appear on metal zippers, cameras, various metal objects they carry with them, and even on their fingertips. Once the thunderstorm ends, all of this disappears. This tip discharge phenomenon, called Elmore fire, has a considerable amount of electricity, and it is one of the important compensating currents that maintain the electric field of the atmosphere on sunny days.

We just happened to encounter this kind of weird weather today, such as thunderstorms. However, we did not see, nor did we want to see, the so-called Elmore Fire.

We leaned against the low-lying earthen ridge, pulling up our coats to cover our heads from behind. We could only hear the endless rumbling thunder accompanied by the lightning that sounded almost uninterruptedly for more than half an hour in the heavy rain. At first, we only felt the rain was cold, but later, we were shivering from the cold. Because it was hail and rain at this time, and our bodies had changed from leaning to curling up. The hailstones as big as corn kernels hit us and made us feel unbearable. In order to protect our heads, we first used our hands to hold up the coats covering our heads to reduce the pain of the hailstones hitting our heads directly. Although our heads were temporarily protected, our hands were hit from time to time, and the pain was equally unbearable. Later, I simply put the specimen clamp weighing six or seven kilograms on my head. As for other parts of my body, especially my ankles, which had been beaten blue and numb, I had no way to take care of them. At this time, I had no idea what Mr. Chen Jiamu, who was more than ten years older than me, looked like.

The thunder and hail that had lasted for more than half an hour finally stopped, and we dared to stand up and look around. A pile of hailstones of different sizes had accumulated around us, and a muddy river had formed under the ridge. Our feet were almost completely in the water, and our bodies were soaked. It was as if we had just climbed out of the water. No wonder we were shivering from the cold.

Part 3

Unwelcome Person

The rain was still falling. We got up and led the yaks to the camp. After walking about a kilometer, we saw a herdsman's tent. We discussed going in to take shelter for a while, to dry our clothes, to warm up, to drink a few bowls of milk tea, and to eat something. At least we had to wring out our clothes and rest for a while, and then leave when the rain stopped or was a little lighter. Who knew that there was no one in the tent except two lion-like vicious dogs. It seemed that the owner of this house must have been blocked on the way to graze by the thunderstorm and heavy rain.

In order to enter the tent, the two of us held the bayoneted rifles with trembling hands, and advanced and stabbed step by step at the two barking and ferocious dogs that were determined to defend our home to the death. Finally, we lifted the willow basket blocking the door and forced our way into the tent.

Because of our occupation, the two dogs were forced to stay outside the tent. However, they still refused to give up, and from time to time they would suddenly lift up a piece of the tent from somewhere around them, stick their heads in and bark a few times. We were caught off guard because we had no idea when and where a dog would suddenly come in. We didn't even dare to wring out our clothes, let alone take off our sweaters and trousers, let alone light a fire and boil tea. We just forced ourselves to sit there for more than ten minutes in a restless and helpless manner.
Hearing that the rain outside had stopped, we reluctantly left the tent and set foot on the road to the camp again. The two dogs were squatting on a high ground in front of the tent. In my opinion, their posture and demeanor were as impressive as two land defenders who had successfully driven away the invaders.