DESROCHES ISLAND, Seychelles — In a striking speech delivered from deep below the ocean's surface, the Seychelles president on Sunday made a global plea for stronger protection of the "beating blue heart of our planet."

President Danny Faure's call for action, the first-ever live speech from an underwater submersible, came from one of the many island nations threatened by global warming.

He spoke during a visit to an ambitious British-led science expedition exploring the Indian Ocean depths. Oceans cover over two-thirds of the world's surface but remain, for the most part, uncharted. We have better maps of Mars than we do of the ocean floor, Faure said.

"This issue is bigger than all of us, and we cannot wait for the next generation to solve it. We are running out of excuses to not take action, and running out of time," the president said from a manned submersible 400 feet below the waves, on the seabed off the outer islands of the African nation.

Seychelles President Danny Faure, left, speaks from insider a submersible of the vessel Ocean Zephyr underwater off the coast of Desroches on April 14, 2019. Nekton via AP

Wearing a Seychelles T-shirt and shorts, the president told The Associated Press after his speech that the experience was "so, so cool. What biodiversity." It made him more determined than ever to speak out for marine protection, he said. "We just need to do what needs to be done. The scientists have spoken."

The oceans' role in regulating climate and the threats they face are underestimated by many, even though as Faure pointed out they generate "half of the oxygen we breathe." Scientific missions are crucial in taking stock of underwater ecosystems' health.

Small island nations are among the most vulnerable to sea level rise caused by climate change, and some have found creative ways to express their concerns. Faure's speech came a decade after members of the Maldives' Cabinet donned scuba gear and used hand signals at an underwater meeting highlighting global warming's threat to the lowest-lying nation on earth.

Land erosion, dying coral reefs and the increased frequency of extreme weather events threaten such countries' existence.

During the expedition, marine scientists from the University of Oxford have surveyed underwater life, mapped large areas of the sea floor and gone deep with manned submersibles and underwater drones.

Little is known about the watery world below depths of 30 meters, the limit to which a normal scuba diver can go. Operating down to 500 meters, the scientists were the first to explore areas of great diversity where sunlight weakens and the deep ocean begins.

By the end of the mission, researchers expect to have conducted over 300 deployments, collected around 1,400 samples and 16 terabytes of data and surveyed about 30 square kilometers of seabed using high-resolution multi-beam sonar equipment.

The data will be used to help the Seychelles expand its policy of protecting almost a third of its national waters by 2020. The initiative is important for the country's "blue economy," an attempt to balance development needs with those of the environment.

"From this depth, I can see the incredible wildlife that needs our protection, and the consequences of damaging this huge ecosystem that has existed for millennia," Faure said in his speech. "Over the years, we have created these problems. We can solve them."

Currently, only about 5 percent of the world's oceans are protected. Countries have agreed to increase the area to 10 percent by 2020. But experts and environmental campaigners say between 30 percent and 50 percent of the oceans outside nations' territorial waters should get protected status to ensure marine biodiversity.

Researchers hope their findings also will inform ongoing United Nations talks aimed at forging the first high seas conservation treaty, scheduled to conclude this year.

Environmental groups argue an international treaty is urgently needed because climate change, overfishing and efforts to mine the seabed for precious minerals are putting unsustainable pressure on marine life that could have devastating consequences for creatures on land as well.

Oceans will be one of the seven main themes of this year's U.N. climate summit in Chile in December.

While scientists with the Nekton mission are nearing the end of their expedition, much of their work is just beginning. In the next few months, researchers at Oxford will analyze the samples and video surveys and put them together with environmental data.

"When we pull them together we can understand not just what we see in the areas that we've visited but what we might expect in other regions in the Seychelles," said Lucy Woodall, the mission's chief scientist.

This is the first of a half-dozen regions the mission plans to explore before the end of 2022, when scientists will present their research at a summit on the state of the Indian Ocean. Billions of people live along the ocean's shores in Africa and Asia.