Chapter 906

When diving, there are different probabilities of encountering Shanghai current according to different diving locations.

The downward current, as its name implies, is the downward current, which can be seen from the bubbles exhaled by the three people's mouths. The originally rising bubbles suddenly spread around in a ring shape, and then began to float down. The two turtles not far away shrank back into the crevices of the rock. At the same time, the three people's vision began to become turbid.

Fortunately, in addition to Zhang Heng, the other two are not novices. It's not the first time that Han Lu meets the current, so he won't be as flustered as a beginner. Han Lu is beside the stone wall. Seeing this, she immediately sticks her body to the stone wall and grabs the stone wall like a gecko.

While Nelly turns on her flashlight, takes a picture of a big rock nearest to Zhang Heng, and signals Zhang Heng to go there. However, she also swims there. Their falling speed is not fast, which shows that the current they encounter is not strong, which makes Nelly feel relieved. In addition, Han Lu and Zhang Heng are very calm.

The most dangerous thing underwater is to be in a panic. Not only can't solve any problems, but the disorderly struggle will accelerate the consumption of oxygen, and the wrong operation is likely to bring more trouble. Because Han Lu has enough diving experience, Nelly is not too worried. What she is really worried about is Zhang Heng on the other side, especially the latter who just asked for a rise, but in a twinkling of an eye I met the current.

But fortunately, so far, Zhang Heng did not show any panic. He swam to the rock with Nelly.

About a minute and a half, Nelly felt the current was getting smaller, so the hitter asked Zhang Heng how much gas he still had.

Zhang Heng looked at the residual pressure gauge, which showed that he still had about 120 bar of gas. The three people didn't stay underwater for a long time, and they basically moved at a depth of about 25 meters. They didn't dive too deep, so the gas consumption in the cylinder was not much, and they were far away from the warning line.

But since Zhang Heng has decided to go up, of course, as a submarine guide, Nelly has no reason to continue diving, but before they go up, they still need to meet Han Lu at Shibi.

Different from the relatively clear seawater before, the visibility in the water becomes very low because of the influence of current, which brings up a lot of sediment and impurities. Nelly turns on her flashlight again, but I don't know if it's because of the lack of power. The flashlight in her hand flashes several times this time, and then gradually stabilizes.

However, when Nelly moves the flashlight to the rock wall where Han Lu is, she suddenly finds that there is no shadow of the latter.

Nelly blinked. It seemed that she couldn't believe what she saw in front of her eyes, because Han Lu was the first to find a place where she could fix her body when she came down, and her condition at that time was obviously out of danger. After that, the three people were separated for less than two minutes. In such a short time, Han Lu had no reason to leave this position.

After that, Nelly turns the flashlight to other directions nearby. Han Lu, the seeker, doesn't receive any goods. Moreover, at this time, Nelly sees Zhang Heng gesturing to her and pointing to the top of her finger.

Nelly thinks that Zhang Heng has found out where Han Lu is, but when she looks up, she sees a strange scene that she has never seen in her diving experience for so many years. She sees that the sea water above them is turning red at the speed visible to the naked eye.

Is this a red tide?

Nelly lives by the sea. Although she has never seen red tide with her own eyes, she is no stranger to this natural phenomenon. Red tide is generally caused by the explosive reproduction or high concentration of some phytoplankton, bacteria or protozoa in the seawater in a short time, which will make the seawater discolor and do great harm to the environment.

However, this sea area is a famous diving site on Naguo Island, and the residents of the island have always attached great importance to the ecological environment. Over the years, there has never been a red tide in the nearby sea area, and the red tide generally affects the upper water. However, Nelly finds that the red on her head is approaching them quickly.

Soon they were surrounded by red sea water. The color of the sea water was very close to the blood of human beings. It was very infiltrating to be in the water, and the most important thing was that they would further reduce the visibility. Now Nelly can only see less than two meters in front of her, and even Zhang Heng's figure on one side became indistinct.

Even with Nelly's rich diving experience, she can't help but feel anxious now. The main reason is that this strange "red tide" appeared not too soon or too late, just at the juncture of their search for Han Lu, which made the next search work suddenly difficult.

Nelly wants to take Zhang Heng up first, and then come back to find Han Lu by herself, because Zhang Heng had asked her to go up before the downflow appeared, but it takes time for divers to go up, because the pressure is different at different depths. When divers are at a deeper depth, nitrogen will dissolve into the blood.

At this time, it is mainly the danger of nitrogen intoxication mentioned before. At this time, nitrogen is dissolved in the blood. If the pressure decreases rapidly, the nitrogen dissolved in the blood will precipitate and cause thrombosis, which may cause divers to suffer from diving disease or lung explosion.

So when she rises from the water, she needs a period of safe stay. It will take at least seven minutes for Nelli to send Zhang Heng to the boat and then come back. It's hard to say whether she can reach her present position in the blood red sea water. At that time, it's hard to say whether Han Lu was still nearby. In addition, the remaining gas in her cylinder may not be enough to support her too much A long search.If at ordinary times, of course, Nelly can choose to take Zhang Heng to look for Han Lu, but because of the influence of this strange red tide, as long as they separate a little bit, they may not see each other. In this bad environment, Nelly is not confident that she can take good care of Zhang Heng when looking for Han Lu.

Han Lu has disappeared. Don't lose Zhang Heng at that time.

After a short time of thinking, Nelly decided to take Zhang Heng up first, because she also had a fluke in her heart. Maybe Han Lu had gone back to the ship one step ahead of them and could see each other when they came to the sea. To be honest, even if she took Zhang Heng to risk looking for Han Lu, it was just a chance.

However, when Nelly is ready to take Zhang Heng to rise together, she seems to catch a glimpse of some dark shadow in the afterglow of her left eye.

Is that Han Lu? Nelly's heart gave birth to a touch of hope, although the shadow just passed quickly, but she still saw the outline, really like a man in a diving suit.

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