22 October 2004

Deep diving

Like any day at work, our first efforts this morning were taking care of the various details that have spilled over from yesterday with the twist that we are doing odd things in an odd place. For me, first off was calling Marty the Blaster. Martin Reed is an explosives expert who is blasting dive holes for us in locations that are too remote to be reached with the Reed Drill we have been using locally. He drills a small hole in the ice, sets dynamite charges down it, and blows one shot to break the ice and another to clear it out of the hole. This morning, I needed to check if he had the Jiffy drill for placing the charges or if I needed to supply it.


The clearing shot for one of the dive holes at New Harbor, one of our remote field camps. Henry Kaiser, one of the divers at New Harbor right now, sent this image to me with the label "Frost Demon."

Other small but critical tasks included trying to find the one socket we needed to install the solar panels on the roof of the dive hut. We need just a small amount of power to run the fan that moves hot air from the ceiling down to the floor where it keeps our dive hole melted open. Everyone at McMurdo Station is trying to reduce our use of fossil fuels and use renewable energy wherever possible, and Joe Yarkin, known as Solar Joe, has built several pods and panels that we can use at our remote field sites. We are installing them in all the dive huts and hope to run New Harbor camp entirely on solar power this year.


Bob and John, our volunteer dive tender, install the solar panel on the roof of the dive hut.

My final morning task was trying to wrest "shared" equipment from the grasp of other researchers. This last effort was unsuccessful, but I was saved by Crary Lab staff who miraculously produced a profiler which will work almost as well as the CTD we planned on. This instrument measures Conductivity, Temperature and Depth (hence the name), all important properties of seawater that we can use to give us information about flow direction and freeze/melt dynamics. One of the wider goals of this research is to add a bit more data to the slowly growing picture of currents in McMurdo Sound. Our understanding of the ecosystem dynamics won't be complete until we incorporate the physical characteristics of the environment into the mix.


Mt. Erebus, something peaceful to look at when you feel like screaming.

At 9 am our dive tender, Father John Joliffe, met us in the lab. Father John is a Catholic priest from New Zealand who shares the small Chapel here with a Protestant Chaplain from the Air National Guard. Their personalities are an entertaining contrast to each other. We packed and loaded all the gear we needed into our vehicles. It is amazing how much equipment we take with us everywhere we go: 6 tanks, all our dive gear, emergency kits and survival bags, sampling gear and coolers to bring the samples back, tool kits, and this time, a solar panel. There is barely enough room for all of us but by the time we are squashed in together the daily nap becomes quite comfortable, cocooned in a nest of down and red nylon. I am nervous about the drive out to Cinder Cones as there are some large cracks that are near our path and we have to weave a torturous route between them to stay on the safe solid ice. So I have been driving much of the time until the others get a bit more experience, and I miss my naps!


Father John, our dive tender for the day, and a couple of Weddell Seals that are using a crack nearby.

We have three goals for our dives today. First is to reimage some settling plates that were placed on the seafloor in the mid 1970s by Dr. Paul Dayton from Scripps Institution of Oceanography. These plates provide a valuable time series, and I feel proud to be contributing to a decadal perspective of settlement and growth in the Antarctic environment. The plates are placed in replicate sets at several depths, so Jennifer and I locate the shallowest ones, at 60 feet, and navigate off them to find the deeper sets. At 130 feet we are paranoid with narcosis and move incredibly slowly, keeping each other in sight every second. It takes only a few minutes to collect the data we need but I am filled with admiration for the researchers who set up this experiment 30 years age. The plates at 95 and 60 feet go smoothly as well and we spend the remainder of the dive slowly ascending up the slope. Jennifer points out a HUGE nudibrach that is unlike any other specimen I have seen down here, we take pictures of it as well as of the many jellys and ctenophores in the water column. At 25 feet the slope flattens out into a long bench that is carved by the ice overhead. There is an immediate difference in the community as well from an established tube mat of polychaete worms to finer sediment dotted by Edwardsia anemones. The predictable annual disturbance from the ice prevents the slower-growing worms from establishing themselves, and leaves space for the rapidly growing anemones.


Andrew drinking cocoa, the only suitable pre and post dive activity.

Our dive finished, we head back to the hole in time to see Kathy and Bob descending. They have two goals: to sample within an old iceberg scour, a place where an iceberg has ploughed away some of the seafloor, again to examine community succession following a disturbance, though this disturbance is natural (as opposed to the sewage disturbance which is anthropogenic or human-caused), and to continue cleaning up from our experiment. Even underwater we are adhering to the "Leave No Trace" ethic and so everything we put down as part of the experiment must now come off the seafloor. While I heartily endorse this effort, I am also glad that it was not emplaced 30 years ago, or the long term data we have been collecting from Dr. Dayton's initial experiments down here would not be retrievable! As we hang at our safety stop we watch the tiny divers working below us in the super-clear water, Kathy surrounded by small puffs of sediment as she collects cores and Bob carefully stacking marker stakes and weights on the haul line for us to pull to the surface.

 
Bob getting the glove treatment. Andrew powdering his nose. Who knew diving was so glam?!

Out of the water, we debrief the dive and realize that the settings on one camera were not optimal. Since some of the labeling on the housing is in red it is unreadable at depth and combined with the loss in mental acuity caused by narcosis this has led to a potential for poor quality data. So Andrew and Mike will go down and reimage the plates. They do so, but encounter similar problems with temporary nitrogen-induced confusion and we have lots of good images of the plates in shallower water but none of the deepest set. We will have to try one more time at a later date!

 
Jennifer trying to explain how hard it is to see red labels at depth, where all the short red wavelengths of light have been absorbed and red looks black. Andrew and Mike showing exactly how it should be done

We return to the lab and work up our samples, sieving and preserving the animals in the cores, freezing samples for chemical analysis and refrigerating samples for physical habitat descriptions. We also continue processing samples collected earlier, transferring them from fixative to a storage solution and preparing them to ship home.


Jenn and Stacy cleaning up

Finally we are finished and head off for an early dinner because this evening we have a scheduled competition with our arch-rivals, Dr. Adam Marsh's lab of Marshians. We are engaged in a triathlon of Antarctic sporting events, and the first head to head is bowling. Please note that we won handily (by one point) last year in the bowling competition, and I am sure it had nothing to do with the fact that we were keeping score or that we had bribed the pinsetter (Yay Ted!) The Marshians are too smart to be fooled twice, and had insisted on an impartial scorekeeper, and the pinsetters commented that they had never seen so many gutter balls. Plus, the Marshians actually practiced at least twice over the last year. And, they had recruited Rob Robbins, Dive God Extraordinaire, to play on their team. But the nail in the coffin was the matching bowling shirts they were sporting. Basic Black livened by leopard print at collar, pocket, and back vents (for freedom of movement when their shoulder muscles bulged on particularly difficult throws), with their bowling names embroidered across the chest how could we compete? It was an ignominious defeat but we are sure to rally at the next event DodgeBall!


Dr. Adam March in his stylin' bowling shirt. Sweet!

Check back for more on worms, ice and life in the freezer

Smiles, Stacy

Lets see the next day!