I live in the Martian wilderness!

[Mars Day 15, 16:00 PM]

Gu Yu returned to the command cabin and went straight to the small photobioreactor that he had been carefully taking care of for seven days.

The once clear liquid inside the glass tube had long since disappeared, replaced by a thick, dark green fluid that flowed viscously under the pump, resembling a tube of flowing jade slurry.

"Xuan, report the biological status." Gu Yu tapped the tube wall lightly with his finger through the glass.

"Reporting to the Lieutenant Colonel. The current optical density (OD value) of the culture medium has reached 2.5."

"The BZ-03 reactor has a total of 6 glass tubes, each with a volume of 3 liters, for a total volume of 18 liters."

Accompanied by Xuanjian's voice, a set of detailed cellular microscopic images were projected onto the HUD. Countless tiny, spiral-shaped organisms were densely packed together in the field of view.

"The cells are in the most vigorous logarithmic growth phase, at which time the spirulina's ability to adapt to environmental changes is at its peak. This is the optimal window for transplantation."

Gu Yu nodded. "It's like an army poised for battle. If they stay locked up any longer, they'll start killing each other because of lack of oxygen and overcrowding."

He took out a polyethylene folding bag and attached it to the drain outlet. He was about to open the valve to let the dark green concentrated algae solution fill the bag.

"Lieutenant Colonel, please wait a moment. We suggest you pause this procedure; we need to reassess the vaccination plan."

Gu Yu paused, startled. "What's wrong? Didn't the environment meet all the standards?"

"Environmental standards are met, but the volume ratio is severely imbalanced."

"You only have 18 liters of algae seed. If you pour it directly into 1500 liters of nutrient solution, the dilution factor will be close to 84 times."

"This will result in an initial inoculation density of less than 0.012 g/L. At this density, spirulina cannot form a canopy shading effect."

"Once strong light is turned on, the single cells will be directly exposed to the high intensity of the light, which will produce a severe photoinhibition effect."

"Simply put, they won't grow; they'll die from the sun. The survival rate is estimated to be less than 5%."

"Xuan, please help me think of a new solution. You know I'm not an expert in biology."

Xuanjian immediately provided the revised operating procedure: "Okay, Lieutenant Colonel. We just need to change our strategy—adopt the 'shallow water start-up, fed-batch cultivation' mode."

"Please go to the backyard and start the transfer pump to temporarily pump the 1.5 tons of nutrient solution from the track pool to the unused 5-square-meter spare pool next door for storage."

"Only 5 centimeters of bottom water, about 250 liters, is retained at the bottom of the main pool."

"18 liters to 250 liters, a ratio of approximately 1:14. This allows spirulina to grow rapidly and proliferate! It's also the perfect golden ratio for propagation."

Gu Yu immediately understood the logic: let them eat and drink their fill in shallow water first, and then add water little by little once they are strong and healthy.

He walked through the airlock into the backyard and directly connected two hoses to the multi-functional interface panel on the outer wall of the Oasis One command module.

First, insert the drain pipe connected to the main runway pool into the [External Return/Suction Port] on the panel.

Then another long pipe was inserted into the [External Water Supply/Output Port] on the panel, and the other end was thrown directly into the spare partition pool.

"The pipeline installation is complete. Xuan, start the circulation pump of the water treatment system."

"Note: Bypass all filtration and distillation units; don't purify all the minerals in the nutrient solution. I need a direct-flow mode!"

"Understood, Lieutenant Colonel. Switched to external bypass circulation mode. Main pump started, 50% speed."

"Buzz—"

A low, rumbling sound of motor vibrations emanated from inside the bulkhead of Oasis One.

A powerful suction force was generated instantly. The water level in the main runway pool began to drop visibly.

The carefully prepared pale yellow nutrient solution circulated inside Oasis One before rushing into the empty pool through the output pipe.

Gu Yu stared intently at the markings on the main pool wall, his hand gripping the communicator tightly.

30 cm... 20 cm... 10 cm...

When the liquid level drops to the 5 cm red line at ankle depth, just above the top of the heating rod and aeration tube.

"Stop! Cut off the main pump!"

"Command confirmed, pumps to stop."

The sound of flowing water stopped abruptly.

At this moment, the bottom of the main track pool was only a shallow pool of pale yellow warm water, like a huge warm bed.

He turned and ran back to the command cabin. This time, he opened the valve under the drain outlet and filled the folded bag with dark green spirulina.

Return to the poolside, insert the tubing from the folding bag, and squeeze the bag firmly.

"Glug—"

The thick, dark green algae liquid slid down the pipe and flowed into the shallow bottom water.

"Glug—"

The thick, dark green algae liquid slid down the pipe and flowed into the shallow bottom water.

With the gentle aeration of the airflow, the originally pale yellow thin layer of water turned into a vibrant emerald green almost instantly.

"Turn on the lights," Gu Yu commanded instinctively.

"Lieutenant Colonel, the current liquid level is only 5 centimeters. You can lock the side wall lights and only activate the No. 1 light strip at the bottom of the pool."

"Command confirmed, activate only LED strip #1."

"Snap." The underwater lights came on.

Because the water layer is extremely thin, the light emitted by just one light strip, a light pinkish hue, penetrates the entire liquid layer without any obstruction.

The originally dark black carbon cloth cover was slightly shiny from the light reflected from the bottom.

Each algal cell greedily breathes under this perfect light, neither swallowed by darkness nor scorched by strong light.

Gu Yu looked at the thin layer of green, his eyes firm but also cautious about the unknown. "Xuan, list out the subsequent operating procedures."

"This is, after all, the first industrialized farming on Mars, and we need a timetable accurate to the hour."

"Understood, Lieutenant Colonel. Based on the current inoculation density and the fed-batch culture strategy, a four-stage workflow has been generated for you."

A detailed Gantt chart is projected onto the HUD, clearly outlining the next few days.

Phase 1: Shallow Water Outbreak Period

"Maintain the current water level of 5 cm and turn on the bottom light bar #1. Utilize the high light intensity and high gas exchange rate to encourage the algae to adapt and enter a period of rapid proliferation within 48 hours."

"Phase Two: Gradual Fluid Replacement Period"

"When the color of the algal solution darkens and the optical density doubles, new nutrient solution needs to be added. Inject it at a rate of 5-8 centimeters per day, always keeping the algal solution within the optimal photosynthetic range."

"Phase Three: Peak Sunlight Period"

"This is a critical point. Once the water level exceeds 15 centimeters, the No. 2 and No. 3 light strips on the side wall will automatically activate the side wall lights. At that time, full-power photosynthesis efficiency will be achieved."

"Phase Four: Steady-state harvesting period (expected in 5 days, Day 20)."

"When the water level reaches 30 centimeters and the system is at full capacity, it enters a dynamic equilibrium. You can extract 20% of the algae solution daily for filtration and harvesting, and replenish it with an equal amount of fresh nutrient solution."

Xuanjian concluded, "Following this process, the factory will be operating at full capacity in five days."

As Gu Yu listened to the intricately linked plan and looked at the hopeful expanse of green water before him, an indescribable sense of accomplishment welled up within him.

"Very good. Strictly follow the procedure and monitor it in real time. Please contact me immediately in case of any emergencies."

"Yes, Lieutenant Colonel." Xuanjian's voice seemed to carry a hint of warmth. "Congratulations on cultivating the first paddy field on Mars!"