By WANG Xiaoxia & YE Qing

The torch-lighting ceremony for the 15th National Games, the 12th National Games for Persons with Disabilities and the 9th National Special Olympic Games was held in Guangzhou, Guangdong province in south China on October 9, in preparation for the events in mid-November and mid-December.

The source of the flame used in the torch, made from material collected at a depth exceeding 1,500 meters in the South China Sea, has been officially revealed.

Relying on China's homegrown "Haima" deep-sea remotely operated vehicle (ROV), the aptly named "source flame" was extracted and ignited from combustible ice on the ultra-deep seabed in September, presenting an underwater spectacle of water and fire. This is the first time in the history of global sports that green fuel obtained from a seabed has been used to light a major sports event torch, combining cutting-edge marine technology with sustainable principles.

Green "spark" from the deep sea

So, where did the creative idea of harvesting "fire" from the deep sea come from?

After multiple rounds of research and evaluation, the executive committee of the Games proposed the concept of "harvesting fire from the deep sea," which aims to implement the principles of "green, inclusive, open and clean," and to showcase the innovative elements, technological advancements, and cultural soft power of the Guangdong-Hong Kong-Macao Greater Bay Area.

The organizers wanted to integrate elements such as strategic clean energy and deep-sea exploration technologies and core equipment, and finally selected the Haima Cold Seep area in the northern South China Sea as the origin of the "source flame" for the Games.

At 14:26 on September 18, the Haima ROV descended to the seabed at a depth of 1,522 meters and reached the cold seep vents. Researchers remotely and precisely controlled the robotic arm to hold a collection chamber and gather combustible ice and gases. The combustible ice was triggered under depressurization, and the subsequent methane gas produced by decomposition became the fuel for the "source flame."

At 16:48, the photovoltaic power generation device on the ship converted solar energy into electricity and transmitted it to the seabed, successfully igniting the gas.

After the successful collection of the "source flame," researchers used the "Haima" ROV to place a permanent marker at the collection point on the seabed, inscribed with the Games' names, to commemorate this seminal moment.

Conquering major tech challenges

As the saying goes, fire and water are incompatible, and collecting fire from the seabed was no easy task.

"The deep sea presents extreme challenges: high pressure, low temperatures, corrosion and darkness. While the 'Haima' ROV can dive to 4,500 meters, the pressure at that depth is equivalent to over one tonne pressing on a fingernail," explained Chen Zongheng, deputy director of the Methodology Institute at the Guangzhou Marine Geological Survey (GMGS).

Collecting the "source flame" required overcoming these obstacles. For instance, the combustion chamber had to withstand immense sea pressure, and specialized cameras needed pressure-resistant housing and precise remote control to document the process.In addition, filming with multiple ROVs faced challenges like maintaining position under pressure and filming in complete darkness. The entire process was recorded by an in-house developed, deep-sea 4K ultra-high-definition camera.

To train for the mission, the GMGS led the formation of a dedicated research team to the seabedin in July 2024. The team's "source flame" collection system overcame deep-sea pressure and sealing challenges, achieving breakthroughs in three key technologies: in-situ combustible ice collection, multi-channel gas flow precision control, and combustion environment maintenance and byproduct management, proving they were ready, willing and able.

All efforts worthwhile

Chen said that the team frequently uses the "Haima" for dives and has full confidence in it, but operating two ROVs from the same vessel is rare and requires extensive debugging.

"Seeing the complete footage of the 'Haima' on the seabed made all our efforts worthwhile," he said. Those efforts helped achieve a global milestone by being a pioneer in deep-sea ROV usage to integrate and deploy an in-situ combustible ice collection, decomposition, and ignition device, with the entire process recorded using ultra-high-definition equipment.

Featuring advanced unmanned deep-sea equipment, cutting-edge energy detection and ignition technologies, and strategic clean energy sources, the "source flame" collection—bridging sports and science—showcased China's innovation in deep-sea technology. It also highlighted the pioneering progress of the Guangdong-Hong Kong-Macao Greater Bay Area in marine equipment manufacturing, deep-sea exploration, and clean energy development.