16 August 2023
When I loaded up a zoom call with Debbie Kelley of the Regional Cabled Array last October to discuss collaborating on a film making use of their underwater footage, the last thing I expected was for her to casually ask if I‘d like to join them on their next deep-sea research expedition. ’That would be wonderful’, I smiled – suppressing the part of me that wanted desperately to jump for joy, punch the air and shout from the rooftops – before we went on to discuss the sites we’d be visiting.
The Regional Cabled Array (RCA) is a network of cabled sensors, instruments and cameras spread out across the Juan de Fuca plate, where varied geological, biological and chemical process have crafted a collection of otherworldly environments at the bottom of the ocean. The Southern Hydrate Ridge, a site of methane seeps where hydrocarbon-rich fluid is squeezed from deep beneath sediments and supports communities of unique organisms. Slope Base, at depths greater than 2 kilometres, where the elusive so-called ‘weirdfish’ is often sighted. Oregon Offshore and Shelf sites, where highly productive waters are influenced by the California current. And last but not least, Axial Seamount, the most active submarine volcano in the northeast Pacific, located 300 miles off the coast of Oregon. It hosts one of the deep’s most mysterious and charismatic ecosystems in the form of hydrothermal vents. Chimneys of grey rock that form as water entering the seafloor becomes superheated and spews back out at temperatures that, in parts of the world, exceed 400 celcius (752 f), crafting towers from the deposition of dissolved minerals and supporting life in great abundance! The presence of specialised bacteria spurs primary productivity in the form of chemosynthesis, a process that parallels photosynthesis in many ways. These vents, to me, epitomise all that is wondrous and majestic about the deep sea.
The vessel for the cruise is R/V Thomas G. Thompson, an 83.5 m (274 ft) long ship owned by the US Navy and operated by the School of Oceanography at the University of Washington. When it comes to marine science, this ship is a powerhouse, equipped with multiple winches and cranes for deploying instruments, an A-frame, a state-of-the-art CTD system, along with numerous well-equipped laboratories and computer rooms. A 9 hour flight brought me from London to Seattle, where Deb was kind enough to pick me up and drive me, along with several enthusiastic students, down to Newport’s NOAA facility where Thompson was docked and waiting for us. Rough weather out at the survey sites meant we had a couple days to acclimatise to life on board while docked before taking to the high seas. Even so, the quirks of living on a ship began to show right away. My cabin is small but comfortable. I’m bunking with another, and the “head” (as the bathroom is called) is shared with our neighbours. One of the drawbacks of this setup is the need to remember to lock both the inner doors, and unlock them both once you leave, or else your neighbours will be quite upset with you when they can’t get in (especially as the seasickness sets in). It’s as we were preparing to set sail on the 13th August that I was told to make sure my computer, bags, and other bits were tied down. Before I could ask “with what?” or “where?”, I was handed a power drill and a handful of screws and told to go to town on the wooden table.
Shortly after we left port, we were introduced at long last to the true workhorse of the expedition, ROV Jason. In the sphere of deep-sea exploration, few tools have revolutionised our understanding of the underwater world like remotely operated vehicles (ROVs). They are robots, tethered to a ship by kilometres of cable and controlled remotely, that open a window onto the deep. A world we once could only make sense of by hauling creatures onto the deck from trawling nets can now be entered and traversed with relative ease under the supervision of an expert team of pilots and engineers. The cameras are our eyes, and manipulators our arms. In the case of Jason itself, developed by the Woods Hole Oceanographic Institution (WHOI), a suite of sensors, sampling instruments, and high-resolution cameras come together to create a submarine laboratory that can study environments once beyond human reach. At the time of writing, Jason is depth rated to 6,500 metres (21,385 feet), which gives the vehicle access to 98% of the seafloor!
As a lifelong follower of deep sea exploration, to be in Jason’s presence was surreal. Here before me was the vehicle that recorded the very first video and imagery of a deep-sea volcano erupting on the sea floor, that had had plumbed and surveyed many of the deep sea’s most renowned and charismatic environments. To my delight, one of my tasks during the course of this expedition would be to operate Jason’s 4K camera from a small workstation in the ROV “van”, as it was called. In truth, it’s little more than two bright blue shipping containers strapped together and craned onto the ship’s aftdeck. A seemingly low-tech approach to controlling such a high-tech vehicle… from the outside, at least.
Upon climbing the steps and passing through the doorway of the control van, I was met with a windowless room filled with towers of blinking lights and servers, neatly bundled coils and pillars of cables running between ports and machinery that looked as if it came straight out of science fiction, all convening at a great wall of screens relaying live video from Jason’s many cameras.
It was in that moment I found myself assured that this expedition and its legacy was something truly special. En par with Mars rover missions. I’m reminded often of the parallels between space and deep-ocean exploration. Naturally, both involve exploring places we cannot enter remotely OR in-person without the use of precision, high-tech, innovative equipment developed by teams of brainiacs. Both are characterised by darkness and mystery, but what intrigues me above all else is the under-appreciated truth that the deep sea is far more challenging to explore than space (and exciting, though I might be a tad biased). We can learn a great deal about distant stars and far-flung galaxies by pointing a telescope at the sky. Point a telescope at the ocean, however, and you’re lucky if you see much more than blurred ripples. The ocean keeps its secrets locked away, and reveals them only once we dare descend into its depths. Even then, the lights of an ROV can only shine so bright before they’re swallowed by gloom.
I witnessed this phenomenon first-hand during our initial Jason dives. Amidst a rise of bubbles, the vehicle’s descent was slow – about 30 metres per minute, give or take – but the dark was rapid in its emergence. I was told the first dive was a test of sorts, and “naked”, without any additional equipment, primarily to ensure everything was working as expected. The control van’s great wall of screens showed the view-feed from Jason’s multiple cameras, pointing every-which-way. But front and centre on the control monitor was the feed from most important camera of all (for myself and the science teams, at least) – the science camera, able to record in stunning 4K. The screen became speckled with marine snow, the slow and steady trickle-down of organic debris and faecal matter that sinks from the productive waters up above. My heart skipped as the first animal appeared. It was a siphonophore, tiny, distant and quick to pass as the ROV continued its descent. For the Jason team, this was an everyday occurrence and little more than background noise in their grand operation, and a sighting that paled in comparison to the ones that lay ahead, but I was overjoyed! More followed. Swarms of jellyfish and shoals of fish, erupting out of nowhere to fill the screens before vanishing just as quickly. Some appeared as little more than silver darting flecks passing in and out of sight as their mirrored skin turned in Jason’s headlights. During my time on board the Thompson, I’ll be filming operations and collecting 4K ROV footage to create a series of films about the RCA and the deep waters of the Juan de Fuca plate. I sat back and settled in to the first of many 4-hour shifts monitoring the cameras, transfixed, my finger resting on the trigger of the 4K recorder.
It was when Jason finished its descent that we caught another glimpse of life in the form of sessile communities that had built up on one of the RCA’s instrumented midwater Shallow Profiler Moorings – a bright orange contraption suspended in the water column and anchored to the seafloor below by long chains. I was told it had been there since 2018. In just 5 years, vibrant assemblages had bloomed and settled, for on its surface were colonies of crinoids (feather stars) clinging on with their finger-like cirri to the wire crawlers and science pods of the mooring, while arms lined with lateral extrusions called pinnules were unfurled into the flow of water where they trapped particles of food and tiny organisms. There were anemones, brittle stars, and squat lobsters, making their homes in the many nooks and crevices, while shoals of shrimp spun around them. For these animals, the moorings have created a perfect opportunity to thrive in an otherwise uniform habitat. On the seafloor below, soft sediments limit the availability of attachment points for sessile creatures such as these, and currents are slower than those of tidal or wind-driven surface waters. But by anchoring to the mooring, the sessile filter-feeders have access to the strong, nutrient-rich waters that heave a greater amount of food past their hungry, coiling arms. In the ocean, complexity drives biodiversity, allowing these 3D solid structures to become islands of life in the midwater expanse.
