During diving, there were different probabilities that one would encounter the sea current, depending on the diving location. As the name suggested, the descending current was also known as the down-current. Supposedly, the air bubbles exhaled from the diver’s mouth would ascend to the surface of the sea. However, if there were currents around the divers, their air bubbles would disperse around them in a ring shape. After that, the air bubble would drag to the bottom of the ocean by the down-current. The two turtles not far away could sense that something was not right. So, they quickly swam back to the crack between the rocks. And at the same time, the three’s vision began to become blurry.
Fortunately, except for Zhang Heng, the other two were experienced in dealing with down-current. It was not the first time Han Lu has encountered ocean currents. Therefore, she did not become panic as a newcomer would. She quickly attached her body to the stone wall, grabbing whatever she could find like a gecko.
Nellie turned on her portable flashlight, flashed at the big rock closest to Zhang Heng, and signaled Zhang Heng to swim towards it. As for herself, she quickly swam towards the big rock as well. Their descending speed was not that fast, indicating that the ocean current they encountered was not that strong. Upon realizing that, Nellie was relieved. On the other hand, Han Lu and Zhang Heng managed to keep calm as well.
The most dangerous thing when one encountered an ocean current was to fall into panic mode. Not only would it not help with anything, but the random struggle would accelerate the consumption of oxygen, and the wrong moves would most likely cause more trouble. Han Lu had experienced diving before; hence, Nellie was not too worried about her. The person she was really anxious about was Zhang Heng. The moment he asked to go back up, they were hit by the undercurrent.
But fortunately, Zhang Heng did not panic so far. The moment he received Nellie’s instructions, he quickly swam to the big rock with her. About a minute and a half later, Nellie felt that the ocean current had begun to settle down. So she gestured to ask Zhang Heng how much oxygen he had left.
Zhang Heng then glanced at the residual pressure gauge, and it showed that he still had about 120 bar of oxygen. The three of them did not stay underwater for too long, and they did not dive below 25 meters. Therefore, the oxygen in their cylinders was still sufficient. It was nowhere near the warning line.
But now that Zhang Heng had decided to ascend, Nellie, as a dive guide, certainly had no reason to continue diving. But before they ascended, the two needed to meet up with Han Lu at the stone wall first.
Before the ocean current hit them, the seawater was crystal clear. However, after the undercurrent swept their diving spot, there was now a lot of sand and impurities floating in the water. Therefore, it caused their visibility to drop drastically. So, Nellie quickly turned on her flashlight again. However, it seemed like her flashlight was running out of power. It flashed a few times before it became stable.
However, when Nellie moved the flashlight to the rock wall where Han Lu was supposed to locate, she found out that Han Lu was gone. Nellie blinked her eyes, and she could not believe what she just saw. When the ocean current hit them, Han Lu was the first person to find a place to stabilize herself. At that time, she was supposed to be out of danger. After that, the three of them were separated for less than two minutes. In such a short time, it did not make sense for Han Lu to leave her position.
Nellie then shone the flashlight in other directions. They were trying to look for Han Lu, but it yielded no result. And at this moment, Nellie saw Zhang Heng gesturing to her and pointed to the top of her head. Nellie thought that Zhang Heng had discovered where Han Lu was. But when she looked up, she saw a strange sight that she had never seen in her life before as a diver. The seawater above them was turning red at a speed visible to the naked eye.
Was that a red tide?
Nellie lived by the sea. Although she had never seen red tides in person, she had heard about this natural phenomenon before. The red tide was generally caused by the phytoplankton, bacteria, or protozoa in the sea. The seawater would turn red when it exploded or multiplied within a short period of time. It was very harmful to the environment.
However, this sea area was a famous diving spot on Yonaguni Island. The residents of the island had always placed great importance on the ecological environment. For so many years, there had never been a red tide in the nearby sea. Under normal circumstances, the red tide would appear at the upper levels of the sea. However, Nellie saw that the red tide was approaching them fast.
Soon the two of them were surrounded by red seawater. The color of the red seawater was actually very close to human blood. The worst part was that their visibility had further deteriorated. Nellie could only see less than two meters in front of her. She could barely see Zhang Heng’s figure.
Even with Nellie’s rich diving experience, she couldn’t help but feel a little anxious now. It was mainly because this weird “red tide” had appeared at the wrong time. It had made their search for Han Lu became even harder no.
Nellie wanted to take Zhang Heng to ascend to the surface first and come back to look for Han Lu by herself. It was because Zhang Heng requested to ascend before they encountered the ocean current. However, it would take quite some time to get back to the surface because the pressure at different depths was different. The deeper the divers dived, the more nitrogen would dissolve into their blood.
There was a possibility that they might suffer from nitrogen intoxication. If they went up too fast, the pressure would decrease rapidly, and the nitrogen in the blood would precipitate and cause thrombosis. If a diver suffered from such a complication, their lungs would burst in the worst-case scenario.
Therefore, one needed to take a break during the ascension to the surface of the seawater. It would take as long as seven minutes for Nellie to send Zhang Heng back to the boat and return undersea to look for Han Lu. Let’s not talk about whether she could return to the exact same spot while being affected by the red sea water. She did not even know if Han Lu was still nearby her. Besides, the remaining oxygen in her gas cylinder might not be enough to support her to search for too long.
Under normal circumstances, Nellie could choose to bring Zhang Heng to search for Han Lu. Due to the red seawater, she might not be able to see Zhang Heng if he went a little too far. In such a bad situation, Nellie did not have the confidence to take care of Zhang Heng while looking for Han Lu.
Han Lu was now gone, and he did not want to lose Zhang Heng too. After some thoughts, Nellie decided to bring Zhang Heng back to the boat first. Besides, she was hoping that Han Lu had returned to the boat on her own. Maybe she would be able to see her again when she resurfaced. And to be honest, even if she took Zhang Heng to risk finding Han Lu now, the only thing that she could rely on was her luck.
Just when Nellie was about to bring Zhang Heng back to the boat, she seemed to spot a dark shadow flashing past her left eye.
Could it be Han Lu? The hope in Nellie’s heart was lit up once again. Although the shadow passed by quickly, she saw that the person was wearing a diving suit.
