Down, down, deeper and down

Deep-sea explorer Alvin is finally being laid to rest, so David Bradley salvages a few thoughts on deep-sea exploration from scientists who don't seem to mind the pressure.

Alvin - Image from NOAAHow do scientists cope under pressure? In the depths of the ocean? In a place where the only natural light is the product of bioluminescence, where high-pressure sales has an altogether different meaning?

Plumbing the ocean depths began in earnest in the 1930s with the invention of the bathysphere. Built by New York explorers William Beebe and Otis Barton it was little more than a 2-tonne steel ball dangling from cables attached to a ship. Beebe and Barton dived to almost a kilometre below the surface off the coast of Bermuda in 1934 and piped details of their findings through a telephone to the crew up top. They reported sightings of fish and invertebrates the likes of which science had never seen before and have inspired a generation of scientists to explore deeper.

Paul Tyler of Southampton University's Oceanography Centre is a marine biologist who regularly dives and has tried out all the deep-sea submersibles except the Japanese Shinkai craft. 'It's like sitting in a refrigerated VW Beetle without the seats,' he told us, 'there are normally three of you in a 2 metre sphere with three portals to look out of, as you get deeper you put more and more clothes on, but it's fantastic, priceless'. But, a 4000m dive can take three hours to reach the seabed, 'so you sleep, read, or chat, but once you reach the bottom, time flies past because you don't want to waste a second, you're so busy, you're either collecting, photographing or setting up experiments,' Tyler adds.

Even graduate students can go deep. Coral biologist Scott France of the College of Charleston made an early start in diving, 'My PhD studies included research on dispersal of crustaceans between hydrothermal vents,' he explains, 'Within eight months of arriving at the Scripps Institution of Oceanography, I made a dive in Alvin to 3800 meters.' Alvin is a submersible operating out of Woods Hole Oceanographic Institution. France realised that no amount of reading would have prepared him for the experience, 'I was ecstatic,' he exclaims, 'I was an explorer venturing to a place on Earth that virtually no other human had seen before, witness to an environment completely alien to most people.' For some the experience can be quite out of this world. 'It takes a few hours to descend to the bottom and is very eerie,' says Emma Jones a fish behaviourist at the FRS Marine Laboratory in Aberdeen, Scotland, 'the sub tends to creak as it sinks which can be a bit disconcerting!' She revisited a dead whale that had been 'planted' on the sea floor 18 months previously. 'The skeleton was a very spooky sight,' she says, 'we were collecting bone samples to see what had colonized them, sediment samples, sucking up amphipods and filming.'

Submersibles are certainly not the most luxurious way to travel, says geologist Paul Aharon of The University of Alabama, Tuscaloosa who has just returned from the Atlantic diving in Alvin. 'It is an uncomfortable ride inside the submersible with three people crammed in among the oxygen tanks, carbon dioxide scrubbers and electronic consoles,' he explains. 'Last dive I almost got hypothermia because I forgot to take long pants with me,' he revealed to us, 'I worked at 3 Celsius with no possibility of moving my legs for over 8 hours!'

He and Tyler also point out that there are some rather personal problems that face anyone on a submersible. 'There is always the question of vital body functions such as urinating...' Aharon muses, 'In addition, the air we breathe has less oxygen and more CO2 than the atmosphere to prevent sudden ignitions. The results are headaches, memory lapses and slowdowns in brain functions.'
Alvin is a titanium-hulled submersible and can remain submerged for 10 hours under normal conditions, although its life support system will allow the sub and its occupants to remain underwater for 72 hours. It makes about 150 dives every year. There are several other equally adept submersibles including - Clelia and the Johnson Sea-Links I and II, which are run by Harbor Branch Oceanographic Institution. And, the Japanese craft Shinkai 6500, which weighs almost 26 tonnes and goes down, obviously, to a depth of 6500m. Shinkai, like the others, carries the requisite TV cameras, temperature and depth sensors, stills cameras and various navigational devices. But, riding Shinkai can be a lonely life since there is room for just one diver.

Discomfort aside, it is the wonder that keeps the scientists going back for more. 'You don't realise what a unique experience entering 'inner space' is,' explains Tyler. 'I went to Axial Seamount on the Juan de Fuca Ridge, which is actually the shallowest of my study sites, at about 1550 m,' says Maia Tsurumi who works with Verena Tunnicliffe on hot vent ecology at the University of Victoria, 'Getting to go down to the bottom in a sub was amazing - definitely one of the highlights of my grad career.' The sites can be almost beyond belief, it seems, 'The most fantastic biological site I have seen in my life is a tubeworm pillar,' adds Tyler, 'it is just unbelievable, 14 high and five meters in diameter, it’s just enormous covered in these tubeworms.'

In October, visual ecologist Tamara Frank of HBOI was about to set sail, when October's Hurricane Iris and Tropical Storm Jerry scuppered her plans. She made her first dive in 1992, and is now studying the effects of light on the daytime depth distributions of organisms with colleague Edie Widder. Their dives need go no deeper than 1000m at the moment, but she is hoping to collect benthic animals too, which would mean much deeper dives. 'Most dives in the submersible are fascinating, seeing these spectacular organisms in their natural habitat is just the most amazing experience in the world.' she told us, 'Once you pass through the air-water interface, you're surrounded by seawater, and don't even realize that you're looking through a Plexiglas sphere because the refractive index of Plexiglas is the same as that of seawater…there's none of this "looking out of little tiny portals" if you're lucky enough to be in the front of the JSL; and the seats are very comfortable!'

'There are too many rewards to count,' Aharon also enthuses. 'First, we descend for hours without lights to conserve electricity and you'll see all kinds of eerie bioluminescence with psychedelic colours. It is a wonderful experience!' he exclaims. 'I wish I had more time to just sit and observe,' laments Frank, 'but on most of our dives in the Gulf of Maine, we immediately have to start transects, which are exhausting, because you're straining to identify organisms that pass through the transect area as the sub goes through the water.' She confesses that science sometimes obstructs the view! 'Both Edie and I have seen beautiful gelatinous organisms during these transects, but couldn't stop and film or observe them because data collection always has priority, and that's sometimes frustrating.' Takeshi Matsumoto of the Japan Marine Science and Technology Center (JAMSTEC) which operates the Shinkai submersible agrees that it is a busy game, 'The most serious problem during a dive is the restriction of diving survey time,' he explains, 'observers have to accomplish everything within a few hours during the dive. Planning and preparation are essential.' Jones agrees, 'Because research vessels cost so much to run, and weather can change so quickly, you do feel you have to make use of every minute available to do your science.'

So, what is the motivation for cramming oneself into a tiny capsule and diving to the bottom of the sea? 'I was always fascinated by the abyss and grabbed the opportunity when it came my way,' Aharon told us, 'I guess my initial attraction started in childhood when I read about Captain Nemo.' Tsurumi agrees that the deep can affect you profoundly, 'There is nothing so romantic and exciting as going somewhere seemingly totally inaccessible,' she says. Aharon is totally hooked, 'It's an addiction, once you start going down (and hopefully, coming up again),' he says.

It is not always so dreamy though. One of the more frustrating aspects of deep-sea science is not diving as Southampton University oceanographer Mark Varney explains, 'I went on an expedition to the central Indian Ocean in June, and found the entire trip something of an ordeal. The weather was bad for most of the period, and the science wasn't terribly successful.'

Indeed, extremely rough conditions are perhaps the worst aspect of doing research at sea. 'On our Indian Ocean trip we were blown out on two occasions (to Indonesia and then towards Australia - both took several days to get back on to station,' adds Varney. Tyler points out that, 'Bad weather and very occasionally malfunctions are the only things that stop us diving.' But, Frank notes, the hazards of diving are overrated, 'I find it much more terrifying driving in Boston than diving in a submersible,' she asserts, 'At least in a submersible, you're being 'driven' by a professional, there's no 'traffic' to worry about, and you know the vehicle has been through an enormous number of safety checks.'

France too is not perturbed by the potential dangers, 'My desire to see the deep sea and its organisms first hand represses rational consideration of the dangers involved,' he says, 'Of course there are dangers involved in travelling to such great depths. One can't simply call for a tow-truck if the sub is stuck.'

'The longest cruise I have been on was slightly over five weeks,' says France, 'and this was as a graduate student. At that time everything was an adventure and so the time passed quickly. Now that I am married, being away for that length of time would be an emotional hardship.' However, at the end of a trip, the coming home can be a problem for some, 'I often get "post cruise blues" after a cruise,' admits Frank, 'as do many of my colleagues, because you go from this exciting, noisy, "happening" environment, where there's always someone to talk to, to a very quiet home.'
But, one question remains…how do they cope with those 'personal' problems during a dive? Jones had her own method, 'I found out I was diving in Alvin at 4pm the day before so I deliberately stopped drinking any fluids from then on as I didn't want to be squirming and crossing my legs for 10 hours,' she says. Aharon, however, explains the standard approach, 'We take capped bottles fitted specially for men and women. Not a pretty site, but we are all human.'

This article originally appeared in HMSBeagle, which has since sunk without trace...ironically enough, although it was fun while it was still afloat and is sadly missed by its trusty crew of writers and even those who had to swab the decks.

Also in Issue 75
The growing problem of biopiracy
Research assistants under contractual obligation

Previously, in Elemental Discoveries:
Accidents will happen
Predicting climate change
Green silicon production
P2P for scientists
Women in science
Academic poaching of researchers
Permanent implantable contact lenses
Profile of ETH Zurich
Paradoxical ozone