Jonathan Timothy Peter Copley(University of Southampton)



Five kilometres - or 3.1 miles - is not a great distance on land; the length of a pleasant walk. But five kilometres vertically in the ocean is a distance that separates two different worlds. So it was with great excitement that I climbed into the metal sphere of the Shinkai6500 this morning with pilot Yoshitaka Sasaki and co-pilot Yudai Tayama, ready to make a dive to the Beebe Vent Field five kilometres below the RV Yokosuka.

Five minutes after we left the surface, we passed 200 metres depth and entered the "twilight zone", where the sunlight from the surface is already too dim for organisms to photosynthesise. The colour of the water outside the porthole became the deepest blue you can possibly imagine - a colour famously described as "luminous black" by deep-sea pioneer William Beebe, after whom the vents below us are named. Beebe and his colleague Otis Barton became the first people to venture into the deep ocean when they dived in their bathysphere in the 1930s, and both are ocean heroes to me.

At 09.29 we passed 923 metres depth -- the maximum depth reached by Beebe and Barton in 1934. Moments later we entered the "midnight zone" beyond 1000 metres deep, where no sunlight penetrates. At 09.56 we passed 2200 metres depth - a personal milestone, as that was the deepest I had been before, but this time not even halfway to the seafloor. And forty minutes later we passed 3800 metres depth, which is the average depth of the ocean. Finally, after sinking through the ocean like a stone for two hours, we approached the ocean floor at a depth of 5103 metres.

To reach the Beebe Vent Field, we travelled across the landscape of the ocean floor, which changed from a flat plain of fine mud to a steep slope of grey lava blocks, and eventually rust-coloured sulfides - the minerals formed by the vents. Soon afterwards, we arrived at our target site: a set of "black smoker" chimneys called "Hashtag".

The hot fluids from these slender mineral spires shoot nearly a kilometre into the ocean above, and sitting next to this force of nature in the Shinkai6500 was a humbling experience. We quickly began collecting samples of rocks, the hot fluids gushing from the vents, and the creatures living around them: pristine white anemones with gentle wafting tentacles, and orange-coloured shrimp crawling over sides of the vent chimneys.

During the few minutes of waiting for our water sampler to collect high-temperature fluids from the vent chimneys, I enjoyed a delicious packed lunch of rice balls, fish, and omelette, with green tea. To visit a Japanese restaurant is a treat in the UK, so my meals aboard the RV Yokosuka have been a rare pleasure, and to dine today at the ocean floor even more so.

Eventually, the time for our visit to the vents was over, and we left the seafloor to begin our return journey to the world above. But the deep ocean had one further gift to give: with the lights switched off during our ascent, I could watch the bioluminescent displays of deep-sea creatures through the porthole: flashes of light in the inky darkness triggered by the passing of our submersible.

By 17.32 the Shinkai6500 was secure again on the deck of RV Yokosuka, where our scientific colleagues were waiting to rush our payload to the laboratories aboard the ship. We hope that these samples will help in the efforts to understand the limits of life, and more about how our planet works.

William Beebe once wrote that if you visit the deep ocean and return speechless with wonder, then you deserve to go again. For me, the wonder of visiting the world’s deepest known vents today will never fade. My team and I from the University of Southampton are profoundly grateful for the invitation to join in the voyage of the RV Yokosuka and Shinkai6500, and for the warm welcome that we have received from all aboard. We look forward to making future voyages together to continue the exploration of our planet’s greatest realm.



5 キロメートル,あるいは 3 .1マイルという距離は,陸上の場合,大したものではなく,むしろウォーキングにはちょうどいい距離だ。しかし,この5キロメートルという距離を,海の深さ方向にとるなら,それは世界を2つに分かつ距離と言うことができよう。

今朝,佐々木義高潜水船船長と田山雄大船長補佐と共に「しんかい6500」にかかる鉄梯子を上り,「よこすか」の直下5 kmに存在する「ビービ熱水噴出域」の潜航調査へ出発しようという時,私は心の底から興奮していた。


船窓から見える海水の色は深い深い青色。あなたも想像することができるだろうか。その色は,深海の開拓者であるウィリアム・ビービ(William Beebe)によって「光る黒色(luminous black)」と表現されている。そう,私たちが向かう熱水噴出域の名は,彼に由来している。

1930年代に、自ら作成した潜水艇「バチスフィア」に乗り込み,世界で初めて深海を冒険したビービと,彼の盟友であるオーティス・バートン(Otis Barton)は,私の「オーシャン・ヒーロー」である。

9時29分,私は 1934年にビービとバートンが達成した最大水深923mを通過した。 その5分後,私たちは1000mを越える「ミッドナイト・ゾーン」(midnight zone)に入った。