The most important facts we don’t know about the ocean

Among the great blue’s many mysteries, here are 4 of the biggest that scientists are working to solve

Radiolaria, one of the known forms of zooplankton that dates back to the Cambrian period, are found on the ocean floor. Picturepest, Flickr
10 September 2019

“Our biggest threat to the ocean is our ignorance of it,” says Margaret Leinen, one of the world’s foremost marine scientists and director of the Scripps Institute of Oceanography.

With nearly 3 billion people depending on its biodiversity for their needs, the ocean is home to more than 200,000 known species as well as a major driver of the global climate. Yet countries only devote up to 4 percent of their research and development budget to ocean science.

In light of this, the U.N. is preparing a decade of efforts dedicated to making rapid progress in the field of ocean science. Launching in 2021 and running until 2030, the initiative aims to rally countries around the importance of understanding the waters that cover 71 percent of the globe, which would paint a better picture of climate change’s causes and solutions.

Here, Leinen and Karen Evans, principal scientist with the Australian research agency CSIRO and member of the decade’s executive planning group, share the foremost of these marine mysteries, and why solving them is necessary for the future.

Ocean floor
The ocean floor off the coast of Dikella, Greece. Dimitris Siskopoulos, Flickr

What the ocean floor really looks like

Experts have photographically mapped the moon, but the world still lacks a comprehensive digital atlas of the ocean. “We know a lot of things about the ocean, but we have not yet imaged its floor, so we are constantly surprised by things we find there,” says Leinen. Imaging could help assess both the state of the ocean floor and the environmental impact of mining it.

The full spectrum of marine life

Experts can easily measure physical and chemical characteristics such as salinity, but biologically documenting the entire ocean is another story. New technology is needed to do so. For example, scientists could use genomic tools to analyze water for genetic traces of life forms and observe how they change as a result of global warming, acidification or pollution.

The capacity of marine species to reproduce and adapt

Beyond identifying the various oceanic species, we must understand how they function – especially in terms of their reproductive capacity and ability to adapt to both natural and man-made pressures.

This knowledge is essential for estimating how many resources of fish and sea plants can be sustainably extracted from the ocean in the long-term and how marine systems will respond. “We can then create sustainable marine-based economies and preserve the services provided by the ocean in the years to come,” says Evans.

Technology could also play an important role here, in decoding marine life. With underwater microscopes and a large computational capacity, for instance, scientists could image plankton regularly and study how they change over time. Likewise, the sounds of many marine organisms – not only whales and dolphins – could be recorded and analyzed with the help of artificial intelligence, Leinen points out.

Monterey Bay Aquarium
Marine organisms on the ‘ocean floor’ of Monterey Bay Aquarium, Monterey, California, U.S. Martin Eckert, Flickr


At a time of global change, there is an urgent need to evaluate the cumulative effects of humans on the ocean. Evans notes that in order to reduce the impacts of pollution, acidification, overfishing and global warming, it is important to understand how these activities are jointly impacting oceanic health.

Another important field of research is the interplay between the ocean and the atmosphere. Take sea spray aerosols, which are microscopic particles carried by the air. “They have viruses and bacteria and are very biologically active, with enzymes that can function for days,” explains Leinen. “Whenever people take in sea air, they are inhaling thousands of microorganisms.”

But what are these sea spray aerosols composed of, and how do they affect precipitation and the climate? The answer could help create a more sustainable future.

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