The submersible dropped from the ocean's surface faster than I had expected. With a loud "psssssss" the air escaped from the ballast tanks and the small craft suddenly tilted forward.
Within seconds, aquanaut Robert Carmichael and I (David Keyton) were enveloped by a vibrant shade of blue, watching streaks of sunlight pierce the water's surface. Soon a large manta ray appeared from the darkness below, gently gliding toward our small craft before vanishing into the distance.
The dive took place off a coral atoll called St. Joseph in the outer islands of Seychelles on a mission to explore the Indian Ocean. This body of water is poorly studied and few scientists have ever ventured deeper than the maximum scuba depth of 100 feet.
For more than a month researchers from Nekton, a British-led scientific research charity, have been using submersibles to dive deep below the waves to document the ocean's health.
Oceans cover over two-thirds of the Earth's surface but remain, for the most part, unexplored.
Their role in regulating our climate and the threats they face are underestimated by many people, so scientific missions are crucial to take stock of the health of underwater ecosystems.
Fishing is no longer the sole cause. Man-made pollution, global warming and the acidification of the oceans are new challenges.
As the oceans slowly soak up heat from the atmosphere, marine species will be affected in different ways. Some will adapt. Some will migrate to cooler waters. Others will disappear, leaving a gap in ecosystems that have existed for millennia.