According to a new study, humans visually record approximately 1,470 square miles, or just 0.001% of the deep seabed. It's a little bigger than the size of Rhode Island.
The report, released Wednesday in the journal Science Advances, arrives debatefully whether the nation will pursue industrial mining undersea for critical minerals.
Some scientists argue that little is known about the seabed world, and that more research on the deep seabed is needed to advance responsibly in extraction activities.
“More information is always useful, so you can make better decisions based on more information,” said Katie Krovbell, a deep sea explorer who leads research and founder of the Ocean Discovery League, a nonprofit that promotes seabed exploration.
Learning more about the deep sea is essential to understanding how climate change and human activity affects the ocean, she said. However, the study also highlights the fundamental excitement of the quest that drives many marine scientists.
“You can imagine what's in the rest of the 99.999%,” Dr. Bell said.
The age of visual documents included in this study began in 1958 with a potential deep sea trieste. Images collected since then have enabled biologists to discover new organisms and provide insight into how they interact with each other, interact with the environment, and marine ecosystems.
It is difficult to study deep-sea creatures on the surface. There are few animals, if any, adapted to high pressures. That's why photos and videos are extremely important.
“There are several habitats that cannot be sampled from the ship,” said Craig McClain, a marine biologist at the University of Louisiana who was not involved in the study. “You have to go to the ROV and do that,” he said.
Obtaining a visual for the seafloor can also be useful for geologists. Before the emergence of remotely operated undersea vehicles and crew submarines, researchers had a more limited approach. Drag a large bucket from the ship, drag it, pull it up and see what's inside.
“They're just going to mess around with rocks and try to sort it out without context,” said Emily Chin, a geologist at the Institute of Oceanography, who was not involved in the new research. “It's like people studying metstones and trying to understand the process of another planet.”
By looking at outcrops of rocks on the seabed in photos and videos, scientists were able to learn how basic Earth processes work. It also helps businesses assess potential sites for mining and oil and gas activities.
However, getting to the seabed is expensive, both in terms of money and time. Dr. Bell could cost between $2 million and $20 million when he explores a deep seabed of one square kilometre. Diving can take years to prepare, but it takes hours to get it wrong. And as the dive is in progress, it progresses slowly. Rovers connected to the ship have limited radii for exploration, and crawling and relocating the ship is boring.
With so many barriers, Dr. Bell wanted to know how much we had seen and how much it was on the ship's floor.
Dr. Bell and her collaborators collected records of over 43,000 deep-sea diving, evaluated the collected photos and videos, and estimated the amount of submarine areas documented by the dive.
Together they estimated that 2,130-3,823 square kilometers of the deep seabed were imaged. This amounts to about 0.001% of the total deep seabed.
“I knew it would be getting smaller, but I don't know if I thought it was very small,” Dr. Bell said. “We've been doing this for almost 70 years.”
The study excludes own dives in places where data is not publicly available, such as military operations and oil and gas exploration. Even if they add a few orders of magnitude more documented areas, Dr. Bell said, “I don't think it's enough to move the needle.”
Much of what deep sea marine biologists know about the seabed is based on their small proportions. The situation, the authors say, is similar to extrapolating information from a smaller area than Houston to all the land surfaces of the globe.
The survey also found that high-income countries lead 99.7% of all deep diving, with the US, Japan and New Zealand at the top of the charts. Most diving was within 200 nautical miles of these three countries. In other words, the authors said that diving could potentially bias what is being studied and where it is located.
“There are many people all over the world who have deep ocean expertise,” Dr. Bell said. “They don't have the tools to allow them to do the kind of research and exploration they want to do.”
We found that dives tend to be in the same area, such as the Mariana Trench and the Monterey Canyon, targeting the same type of feature of interest, such as hydrothermal holes. And since the 1980s, most deep dives have been in shallower and more coastal waters. This leaves many areas of the deep ocean unexplored.
“This study is a good review of where we are and, literally, where we need to go to the deep waters,” Dr. McClain said.
