The day begins, for some, at 6:00 a.m., when breakfast is served. I, however, never make it to breakfast. That last hour of sleep is worth too much to me. Rolling out of bed at 7:00, I am at the Dive Locker by 7:30 to begin preparing the gear for the day’s activities.
Our day’s objective is to collect sediment samples and sea urchins from Bernacchi Bay, located at about 76oS on the continent of Antarctica, almost due south of New Zealand. The team with which I am working is from Moss Landing Marine Laboratory, in California. John Oliver has been funded by the National Science Foundation to study the effects of pollution on the marine fauna of Ross Island, particularly in the vicinity of McMurdo Station, Antarctica’s largest research station.
The goal is better understanding
One major facet of their work involves comparative mortality rates of Antarctic benthic life. They worked primarily with three species of animals, a clam (Laternula elliptica), and two species of amphipods, closely related to shrimp. The team collects enough animals of each type to yield statistically valid results. They also collect sediment samples from different areas, some of which are pristine and undisturbed, others of which are from polluted areas.
Half of each type of animal are placed into one sediment, for example from polluted Winter Quarters Bay
The other half into another sediment, perhaps from the pristine Cinder Cones area.
After a predetermined amount of time, they count the surviving animals, to determine the number of deaths occurring.
The clean sediment is used as a control, to see how many of each animal could be expected to die naturally.
The excess loss in the other sample is deemed to be due to stress induced on the animals by pollution.
Some of the experiments are carried out in the laboratory, others are conducted underwater in specially constructed containers.
Packing for the day
We spend an hour collecting and packing the equipment for the day.
Two scuba cylinders per diver
two regulators per person
sleds to haul the equipment
excess clothing to cover any emergency survival situation
a chain saw
nets and ice breakers to clear new ice from the hole
buckets for the animals and sediment
…the list seems to go on forever. Yet, it is all important. Our very lives may depend on an item as seemingly banal as a shovel, should a storm come in and we find ourselves stranded there.
Bernacchi Bay is about sixty miles from our support facilities. We load everything into a Huey twin jet engine helicopter flown by United States naval personnel for the trip there. Four of us are squeezed inside, surrounded by our gear, which is stacked to the ceiling. Forty-five minutes later, we land on the sea ice, between two grounded icebergs trapped there last year when the ocean froze. There they leave us, planning to return twelve hours later when our work is done.
Setting up camp for the dive
Our first job is erecting the tent. This not only gives us a place to change into our diving dress, safe from the wind, but serves as our emergency shelter should we have to stay unexpectedly due to deteriorating weather or mechanical difficulties with the helicopters. A stove is set up to provide water and hot drinks for the research team. Around the tent is strewn our other equipment, which seems to explode from the tightly packed bags in which it was transported. Soon, it looks like a refuge camp.
Two divers are dispatched to the dive hole. The hole was created yesterday, using 53 pounds of explosives to blast through the thirteen feet of ice covering the ocean at this point. It took three people eight hours to clear the resultant loose ice and brash generated by the blast, which is necessary to prepare the aperture for the divers. Today’s team only has to clear the residual ice which formed on the surface since yesterday, a relatively easy task.
The first team dresses while the second team provides surface support. Down lines with flags affixed are installed to allow the divers to find the hole underwater. Tethers to the divers are not used, as the 600+ foot visibility readily allows the exit to be seen. This is significantly different from ice diving techniques used in the continental United States. Two complete regulators are attached to each cylinder, using a slingshot valve. This ensures a supply of air should a regulator freeflow from freezing, a not uncommon occurrence in the 28.6oF (-2oC) water. The divers don gloves which are first filled with hot water, maximizing comfort duration while using three-finger neoprene mittens. Finally, Hunter Lenihan and I help Krist Hammargren and Rick Morrill into the water. Masks are not spit into to prevent fogging, as it immediately freezes to the mask and obscures vision.
Then the diving begins
Krist and Rick will be collecting eight sediment samples from this uncontaminated region to use as control environments. The dive is terminated when Rick’s first regulator freezes up, followed shortly thereafter by a malfunction in his second regulator. He’s not happy with the situation, but ascends safely.
Diving safety is a strong concern when diving in these remote locations. While a recompression chamber is maintained at McMurdo, transportation times range from a minimum of one hour to potentially days, depending on the weather. Thus, any diver suffering from a serious malady such as decompression sickness or arterial gas embolism faces significant delays before treatment is available. On-site oxygen is always carried by the dive teams regardless of the location of diving activities.
The second dive quickly follows. The same dive hole is used by Hunter and Krist, where they descend to collect another set of sediment samples. They finish their dive uneventfully, completing the sediment collection.
Now a break for lunch
The stove is started to heat snow to make water, tea, and apple cider. It is a calm, warm day, with temperatures hovering around 15oF (-10oC), so the group eats outside while enjoying the sunshine. We share cabin bread, cheese, nuts, and granola bars. A skua, the only gull generally seen this far south, sneaks up and steals a bag containing a pound of cheese, flying away with it after being chased. As this represents half of our cheese, we keep a much closer eye on the remaining food.
After lunch, we move 1/2 mile to a different site, near one of the grounded icebergs. Gear is loaded onto sledges, which we then pull by hand to the new hole. Several round trips are required before all of the requisite equipment is available. This hole was one which was kept open through the winter by the Weddell seals, who use their teeth to chew newly formed ice, thus maintaining their breathing stations. We have merely to enlarge the hole with shovels and ice breaking bars to make it adequate for diving.
A new objective
Our objective is to collect heart urchins from the bottom, which is at a depth of 109 fsw. The urchins will be used in the comparative testing described earlier, once we return to McMurdo. Hunter and prepare to dive, sliding into the clod, clear waters. Below the ice, it darkens rapidly. Brilliant blue light spears into the depths, a column broadcasting a friendly message, our beacon to the surface. At the edge of the iceberg, a thin region of ice allows a diffuse glow to light its sides, down to a depth of fifty or sixty feet, at which point the sides of the berg curve in under the upper portions and are hidden in darkness. As we sink to the bottom, we turn on our lights and begin our hunt.
Life is sparse here, on this sandy substrate
Scallops litter the bottom, each about four inches across, and one-inch high anemones extend their white tentacles looking for nourishment. A group of nine or ten pycnogonids (sea spiders), the largest about seven inches across, are feeding on a jellyfish which has had the misfortune to become ensnared on the bottom. A few gastropods, marine snails, crawl about. And occasionally we find our prey, the two to three inch wide heart urchins. These we carefully place in our collection bags, gathering seventeen of them during our twenty minute dive.
We ascend upwards near the sides of the immense iceberg, gliding along its smoothly sculpted ice walls. On the walls are small strands of diatoms, the beginning of the plankton bloom soon to come. Amphipods crawl on the side, and a lone bright yellow crinoid waves its feathery arms in the dark waters. Finally, we reach the ice ceiling, and swim back to the entrance hole for a safety decompression stop.
We then begin the process of sledging back to the original hole for one final collection dive, which Hunter and I do together. Surfacing, we are helped from the water with our bulging collection bags, the contents of which are quickly transferred to five gallon buckets. We strip off our equipment, which has started to freeze solid as soon as we emerged from the water, and rapidly change into dry clothes.
We settle down for supper
It is now almost nine o’clock. Although it is late, the sun still rides high in the sky. It will be months yet before it sinks below the horizon. We dine on the remainder of our cheese and biscuits, and melt yet more snow for hot drinks and soup. Afterwards, we pack our equipment and await the landing of the helicopter.
While waiting, we have time to admire the breath-taking scenery… vast plains of ice-covered ocean, intermittently broken by last year’s icebergs which did not make it to open ocean before being trapped by the rapidly forming sea ice of fall… the ice covered ranges of the Queen Victoria mountain range proudly thrusting her peaks skyward into the cold, clean air… and the mysterious dry valleys, where the snow is shattered and sublimated by the adiabatically warmed winds tumbling from the peaks….
Finally, we hear the drone of the approaching helo, and light off a smoke canister to help them judge wind drift. Carefully we load our gear, and our precious specimens and sediments. Gently lifting off from the ice, we wing our way back to McMurdo, and the lab work required to ready the samples for the morrow.
Then, at long last, we trudge to our rooms in the early morning sunlight, exhausted but exhilarated, to rest before beginning again in the morning.
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