Tubeworms, which exist without a mouth, gut, or anus, are just one of the finds from the first ever dive in a submersible into the crater of a undersea volcano which lies on the Kermadec Arc northeast of New Zealand.
“It is the first time that tubeworms have been recorded in this part of the Kermadec Arc,” said New Zealand project leader Cornel de Ronde of Geological and Nuclear Sciences Ltd (GNS).
The New Zealand scientists and their colleagues from Japan made six dives in total, four of them into the caldera or crater of Brothers volcano. Scientists believe there could be up to 90 submarine volcanoes along the TongaKermadec Arc, a 2500-kilometre stretch of seafloor between the Bay of Plenty and Tonga. Brothers is one of the most active.
The scientists chose the crater of Brothers volcano for exploration because it has at least five very active hydrothermal vents, which pump out hot, acidic, mineral-laden fluids.
Inside the crater were “fields” of chimneys, sometimes numbering 50 or more, venting mineral-rich fluids at up to 300 degrees Celsius.
As we descended, we first saw thick black smoke out the windows at 1600 metres. This means the hydrothermal plumes are rising 50 to 100 metres above the vents in Brothers volcano. That tells us straight away that we have vigorous hydrothermal venting directly below the sub,” said Dr de Ronde.
Using the sub’s praying mantis-like manipulator arms, the scientists collected several chimneys for analysis back on land. Many were 2 to 3 metres tall, with some reaching 6 metres in height.
“Chimneys grow continuously until they become unstable and fall over. Then the process starts again,” says Dr de Ronde.
The scientists were able to gather fluid, gaseous, and geological samples, as well as filming and collecting an array of vent-related animals — shrimps, limpets, crabs and the tubeworms.
It is a unique group of organisms that thrive in this hostile environment, under extreme pressure, in total darkness, next to extremely hot fluids and in a cocktail of chemicals that would be fatal to most life forms on the earth’s surface. These organisms are relatively new to science — the belching underwater chimneys or ‘black smokers’ were only discovered in 1977 — and knowledge of their biology and physiology may lead, scientists hope, to significant advances in industries such as pharmaceuticals.
The deep-sea exploration is a collaboration between GNS, a New Zealand public research institute, and the Japan Agency for Marine-Earth Science and Technology (JAMSTEC).
JAMSTEC brought the world’s deepest-diving submersible, Shinkai 6500, to New Zealand for the project. The 26-tonne vessel can take a crew of three to the bottom of the ocean for eight hours at a time. Typically, the submersible takes about an hour to reach a depth of 1800 metres and then spends five to six hours exploring at that depth before returning to the surface.
The diving project is part of a long-term GNS programme to find out more about the ocean floor within New Zealand’s 200-mile Exclusive Economic Zone. Exploration in New Zealand is expected to continue next March when a 20-dive programme using two subs is planned.