I will never forget my first hour when I arrived in Bermuda by cruise ship. It was seven years ago, in May.

I had been working on board for five months and had visited many tropical islands. I loved to sit and look at the endless expanse of the ocean lit by the rising sun on the deck of the ship.

I felt I had a date that day with the ocean. Having sailed thousands of kilometres, I thought I already knew it very well. It turned out not to be.

Bermuda greeted me with bright sun and strong winds. I passed the control point at the cruise ship terminal and ran as fast as I could along the dock to the ferry, which was already rumbling and ready for departure.

Out of breath, I climbed on to the upper deck and ... “Look at this water!” I shouted to my friends. “It is turquoise!” I was as amazed and delighted as a happy child seeing a new toy. My friends laughed at me. They had already visited Bermuda.

All the way to Hamilton, I looked only at the water and I could not see enough of it. I could not imagine that the water could be that colour and so clear and clean. It was a miracle that still surprises me.

After living in Bermuda, I slowly got used to swimming in water of such purity and exquisite colour; to see healthy corals, to watch bright blue and green parrot fish so close I could almost touch them, to walk on clean and brilliant white sand beaches.

It is not the same in many other beautiful places.

Two months ago, when I walked on to a beach in Bali, Indonesia, for the first time, I wanted to cry. I was in shock. It was painful to see plastic bottles piled in heaps, countless pieces of plastic lying everywhere on the grey sand. There was waste water from hoses flowing in turbid streams from the hotels into the ocean.

“I don’t want to swim here, I can’t even walk on this beach,” I said to my husband Bill in despair. He decided to show me his favourite place for snorkelling in the far north of Bali. It was the magical place where he fell in love with diving in the Pacific Ocean 12 years ago.

We drove for five hours on a winding mountain road until we reached the remote Menjangan National Park. Early the next morning, we were on a small boat headed to an island near the shore that Bill excitedly told me would change my entire vision of beauty in the underwater world.

I was breathless in anticipation as I slid over the side. I knew I would see a landscape of stunning biodiversity with huge corals and great schools of exotic fish. “It’s like going to Disney World!” Bill said with a smile.

I jumped into the water and the first thing I saw were countless plastic bags floating right in front of me. I looked down and saw a bottom of rubble that looked like broken white chalk. It was a wasteland of garbage with a few stunned-looking little fish milling aimlessly.

Bill was inconsolable and could not believe that such a dramatic transformation was even possible. We motored over to another place and we saw the same scene, just slightly better; a few fish and the odd coral. There were young snorkellers from Europe with us on the boat. To our surprise, they admired this underwater world and climbed back in the boat with smiles. “They can’t even imagine what this water, these corals and fish should look like,” Bill murmured with his head in his hands.

In the evening, we talked for a long time about the ocean, coral reefs, fish and global warming. Bill showed me a shocking video he shot a couple of weeks earlier on a dive trip to another pristine area of Indonesia, the Komodo Islands. On the isolated beaches of that national park, accessible only by several days of boat travel, the famed Komodo dragons were paddling on the surface through a vast sea of plastic. These rare lizards, up to ten feet in length, the last remnants on Earth from the dinosaur age, were drowning in floating plastic trash! I could not believe my eyes. “Is it really happening so fast? Am I witnessing the end of the underwater world?”

When we returned home to Bermuda, we drove straight to Church Bay. We sat for a long time just gazing at the breaking waves. I thought about how we all live on the shores of one ocean, not many. The sea is ours to love and protect.

•Nina London is a certified wellness and weight-management coach. Her mission is to support and inspire mature women to make positive changes in their body and mind. Share your inspirational stories with her at ninalondon.com