In almost any human endeavor there is a holy grail, a goal desired, dreamed about, long sought and seldom realized. It’s the kind of thing you think about and hope for, but never really expect to come true. For me it was cold-water coral reefs.

When we think about coral reefs, we usually imagine a tropical idyll, snorkeling or diving in warm, clear water surrounded by shoals of rainbow hued fish. But there are also corals that build reefs in the dark, cold waters in the depths of the world’s oceans. For hundreds of years fishermen in the North Atlantic have been finding broken pieces of limestone coral skeletons in their nets, fragmentary evidence that puzzled scientists of the time. Only in the last few decades, as deep-sea exploration technology has improved, have scientists been able to study these mysterious reefs. We now know that there are a number of species of cold water reef-building corals, found all over the world, and that like their warm water cousins, they support communities of many other kinds of animals.

Stetind, the National Mountain of Norway, soars above Tysfjord. Photo by David Cothran. All Rights Reserved.

One of the best places to find cold water coral reefs in off the coast of Norway, a place I have explored each summer for the past 11 years as the Undersea Specialist on the National Geographic Endeavour and the National Geographic Explorer. These reefs are much too deep for me to reach as a diver, but they should be well within the reach of our ROV, the little robotic submarine that I described in my last post. So I have looked for them, and looked, and looked, and looked! The idea of these corals, living under the Norwegian midnight sun, yet in the permanent darkness of the deep sea, really caught my imagination and I knew it would be something very special to show our guests.

Every time I planned an ROV operation anywhere in the North Atlantic, I had the cold corals in the back of my mind. And that’s the way things stayed until the summer of 2010, when we returned to the spectacular waters of Tysfjord, a long, branched fjord, north of the Arctic Circle in Norway. A couple of years earlier I had explored a huge submarine cliff there with the ROV, descending to around 600 feet below the surface. This time I was determined to go deeper.

As I controlled it from a Zodiac on the surface, the ROV powered down, past bands of kelp and anemones, and then through a region dominated by large sponges, leaving the light behind. I recorded a few interesting, deep-dwelling fish and pressed on, ever deeper. And, at last, there they were, dense vine-like structures of limestone, clinging to the vertical granite of the cliff, bearing lacy coral animals on their tips! In the spaces between the stony branches were shrimp and squat lobsters, anemones and file clams, all the expected members of the community. These were reefs of Lophelia pertusa, the most common of the cold water corals of the North Atlantic, but the first ones ever discovered in Tysfjord. It was another feather in the cap of our little ROV!

ROV image of Lophelia pertusa corals at 750 feet depth in Tysfjord. Photo by David Cothran. All Rights Reserved.

As I had anticipated, the images I took that day were a thrilling addition to the voyage for everyone on board the National Geographic Explorer, and sharing them was a very proud moment for me. So what is the next holy grail for our explorations with the ROV? Cat sharks! I have seen one, briefly, off Corsica. Now I want more!

Categories: Science Milestones