Follow Dr. Katrina Edwards, as she explores the microbial life at the bottom of the Atlantic Ocean
Happy day happy day! We landed the CORK and unhooked from it successfully – our final CORK is in the hole! Signed sealed and delivered, our CORKs are now nice and safe and we won’t see them again until next year when we return to North Pond to sample from our CORKed well-heads and install more instrumentation.
It was a marathon of a day – we were lucky that we started the CORK installation before the crack of dawn, but not much more before. Starting such an operation at the very beginning of a day make the long day tolerable – starting at say 11pm, which we had feared for awhile, is gruesome. At 5am we had assembled the bottom pipe assembly at the rig floor – this bottom assembly is a series of what are called “drill collars” that are basically slotted steel rings that weigh down the casing assembly.
These collars are rusty and greasy, so we clean them on the moon pool dance floor (a grating that covers the hole in the middle of the ship that is the moon pool) and then coat them with an epoxy based paint. This has to be done quick so we have many people out there with rags, ethanol, and paint cleaning and slapping on thick paint. We do this because the iron in steel and the grease both can feed microbes and we want to avoid unintentionally introducing artifacts into our system of study – we wish to study these microbes ‘ au natural ‘.
After the drill collars, we then cross over to our main casing, which is constructed of fiberglass – a much better material for doing microbiology underground, and it turns out is the industry standard in the continental realm. Not so out here in the ocean, and we were met with a lot of skepticism when we first explained that we wanted to use fiberglass to case these holes. Turns out fiberglass worked great! And some of the components that we also had to adapt to be compatible with fiberglass – like centralizers and banding – were better than what the drillers here were using previously, so it’s very likely they will use at least some of these components now routinely.
As we assemble the pipe, we put in 3 packers at different levels to create our experimental observatory intervals. Packers, like inflatable tires in the hole, seal these different intervals so that they are hydrologically isolated from one another, permitting us to do discreet experiments at different depths and geochemical/physical conditions within a single hole.
After the casing is all assembled, then we line up our experimental packages that get inserted in the middle down a long cable. This is quite an amazing feat to observe – hundreds of meters of long skinny tubes containing all the materials that we hope to come back and collect to examine for microbiology and chemistry in a few years – all lined up and hoisted from the rig floor to be lowered into the CORK head and casing. Then it is all sealed up and sent down to the seafloor. The main job is done then – after 30 hours of straight work in this case – but there are just a few more critical steps to completing the job. One, getting the CORK in the ground – always a bit nerve-wracking. Two, unlatching from the CORK – which we’ve see go horribly wrong on this expedition already – we were not eager for a repeat event.
For my part, while I’m just a microbiologist - not an engineer, driller, or even particularly strong and thereby useful at hefting things around – I still like to be there at the moon pool an on the rig floor during the entire series of operations. If just to hand tools and help in small ways, I get to see everything first hand, start to finish, which is really important to me. That’s the only real way to figure out how things work, and to be able to carry out intelligent conversations with those that make this whole program hum – the engineers and drillers. Learn their language, the tricks of the trade. Bubba, the lead driller, or “tool pusher” (his official title), and Tom, my lead engineer, appear to have great patience and tolerance for me and questions, rags, ethanol and paint during operations, for which I am very thankful.
Now we are on to coring again – this time for sediments – and I just heard “core on deck” so I guess it is time for me to run. Wait… it must that time in the cruise – I just heard an audible groan in response to this call – oh… that was me!