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‘Over 90% of the ocean is still unknown’

We have travelled to space but haven’t yet understood our oceans, says marine biologist Sylvia Earle

Sylvia Earle during a 2017 expedition to a Hope Spot at Cabo Pulmo, Los Cabos, Mexico
Sylvia Earle during a 2017 expedition to a Hope Spot at Cabo Pulmo, Los Cabos, Mexico (© Rolex/Kip Evans)

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We have travelled beyond the moon but know little about our oceans, the source of half the oxygen on Earth. “Much of it is unexplored,” says Sylvia Earle, one of the world’s leading marine biologists and deep-sea explorers. “If it dies, humanity can’t survive.”

Earle, 86, often referred to as “Her Deepness”, has been exploring ocean life for half a century. She has logged over 7,000 hours underwater, led over 100 expeditions, and was the first woman to be named chief scientist of the US National Oceanic and Atmospheric Administration. In 1970, she led an all-female aquanaut team expedition, spending 14 days at an underwater research station as part of the Nasa-US Navy Tektite Project. Nine years later, wearing a special metal diving suit, she broke the world record for untethered diving, descending 381m into the Pacific Ocean. In 2009, in collaboration with watchmaker Rolex, she set up Mission Blue, a non-profit dedicated to saving the ocean’s most precious habitats. She calls these areas, critical to ocean health, Hope Spots (the Sargasso, Azores and Costa Rica Hope Spots are currently active). 

Also read: The creatures of intertidal zones

In an interview with Lounge, Earle, a Rolex testimonee since 1982, talks about the present and future of our oceans. Edited excerpts:

When did this “love affair” start?

I first fell in love with the ocean when I was three and got knocked over by a wave on a beach in New Jersey. The ocean got my attention but what has held my attention all these years is life in the ocean. I wanted to be an ecologist before there was a word to describe it.

How have the oceans changed?

Since I began exploring the ocean as a young scientist in the 1950s, more has been learnt about the nature of the ocean and why it matters to everyone, but, at the same time, more has been lost than ever before in history. We now know that the ocean governs climate and weather, shapes planetary chemistry, holds 97% of Earth’s water, generates over half the oxygen in the atmosphere, captures much of the carbon dioxide, and provides a home for most of life on Earth.

The ocean is the cornerstone of Earth’s life support system. In short, no blue, no green. No ocean, no life. We also know that half the coral reefs, kelp forests, mangroves and coastal marshes have disappeared, and about 90% of the wild fish popular on menus globally are gone or are in serious decline. Tunas have been hard-hit, owing to their high value for luxury markets. The chemistry of the ocean is changing owing to acidification from excess carbon dioxide that becomes carbonic acid in the ocean, coupled with land-based toxics and wastes that are deliberately discharged into the sea or flow from groundwater and rivers.

So it’s all gloom?

There is some positive change. There are more whales and turtles today than when I was a child because most nations are protecting them. Where protected areas have been established, the fish and other creatures are recovering.

What are the biggest challenges?

The ocean is in serious trouble because of human actions in the past 50 years. There’s a rise in demand by a population that has more than doubled.Technologies developed for wartime are now being applied with great speed in shipping and to find, capture and market ocean wildlife on an industrial scale.

Sonar developed for submarines is being used to find fish. Enhanced navigation makes it possible to return to precise locations where species are abundant. The ocean is clogged with discarded or lost drift nets, long lines, traps and other gear that entangle and kill millions of fish, marine mammals, birds and other creatures every year. Illegal, unreported and unregulated fishing removes or destroys millions of wild animals every year in addition to the 100 million-plus tonnes of ocean wildlife that is taken legally.

Entanglement and ingestion by wildlife on the land and in the sea is a huge problem but even more worrisome is the impact of micro- and nano-plastics. Some are toxic and most attract toxins and bacteria with the potential to do harm. These small pieces are now in the air, water, soil and bodies of many forms of life, including humans. Those who dine on ocean wildlife are exposed to what those animals have been swimming in and consuming.

How can we protect the oceans?

We need more stringent measures when it comes to pollution, fishing, and marine life. It is also important for people to understand their ability to protect the planet. One has to recognise the unprecedented knowledge that now exists that did not—and could not—be known before. Then, one must use their powers to make a difference. As I have said, no one can do everything, but everyone can use what they have that is special to them to turn planetary decline to recovery, to the goal we must embrace for an enduring, prosperous future.

Each of us individually and all of us collectively must respect and care for nature, treat the ocean and the rest of the living planet as if our lives depend on it, because they really do.

How can people contribute?

It is an illusion to think that anyone could live without the ocean. Even if you never see or touch the ocean, it touches you with every breath you take, every drop of water you drink. Similarly, every action anyone takes anywhere ultimately has an impact everywhere. Small things make a difference, such as toxins you flush down the drain that ultimately reach the ocean or the choices you make about what to eat—or not. No one can do everything but everyone can do something to help maintain a favourable planet.

Do the oceans still hold any secrets for you?

Over 90% of the ocean is still unknown, unexplored, not even mapped with the same degree of accuracy that we have for the land or for the Moon, or Mars.

And that’s what motivates your work?

The ocean is perennially evolving. Every dive I go on, I see something I have never seen before. It does not always have to be a new species, but new behaviours, new insights into how the ocean functions. What happens in the deep sea or shallow sunlit reefs affects what happens on the surface. To me, ocean means life. It is the foundation of everything we do.

What’s your mission at the moment?

When we started our journey, our quest was to go where no one has gone before. Now we have another ambition: to garner a better understanding of the planet, to grasp its fragility to comprehend what we can do to better protect the planet and its oceans.

Any unforgettable experience that still takes your breath away when you think about it?

It will always be the first scientific expedition that I had an opportunity to participate in. It was a six-week expedition to India in 1964. I was there as a botanist but was the only woman on board. There were 12 scientists. All the others—most of the 70 men—were crew. It was really a turning point because every time we put a piece of equipment into the water and brought things back from the deep and had a chance to look at them, we saw things no human had ever seen before.

And, as I said earlier, it’s still true that much of the ocean is still unknown. It was also a great lesson for me about the limits of who we are as air-breathing creatures to explore where most of life on Earth actually lives. 

Also read: Giving nature the right of way

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