Follow Dr. Katrina Edwards, as she explores the microbial life at the bottom of the Atlantic Ocean
We have drilled through sediments to upper most basement in order to put in casing that will prevent this hole from collapsing – Hole 1382A, or the first hole (A) for this new site (1382). When we come back here in about a month to core sediments (we aren’t recovering any sediments during present operations), this second hole is called the B hole, and then perhaps we’ll get a C hole and a D hole, and so on. And such are the naming conventions of the IODP.
After we are done with our casing we will begin coring operations here – yay! Finally to lay my hands on some samples. Spirits have been high around here with everyone excited about coring our first hole. We are actually not completely certain we’ll get back here to core even the B hole for sediments, but with a bit of luck – well, really if we don’t have any more disasters or tropical storms – our odds are pretty good we will. That will make a whole bunch of sedimentary microbiologists very happy.
I’ve talked a lot about observatory science on these blogs – the science and the operations. This next phase of operations will be entirely different, as we will be recovering core on a 24-hr schedule for several days. Teams of samplers – microbiologists and petrologists – will split the samples according to what kind of rocks we drill into and then will divide up and sub-sample for the various science programs.
Sampling rocks that are recovered from the subseafloor for microbiology is tricky. For petrology, you can simply cut samples using a saw any way you see fit. For microbiology, it’s all about contamination – dealing with contamination on the exterior of the samples that come up and then dealing with the subsampling without introducing new contamination.
So, samples that are recovered are first carefully rinsed with sterile seawater to remove contamination, and then are sampled in specialized sterile microbiological boxes using flame-sterilized chisels of various sizes. We then split samples using these chisels and a rock hammer. It is crude work for microbiology, but there just isn’t any other way to do it. Some samples get further crushed using a sterile rock-crusher for starting microbial cultures or doing incubations – i.e., shipboard biogeochemical assays.
Bubba the driller (he’s the guy in the bib overalls who made all of his guys wear those blue gloves for us out on the rig floor – shown in an earlier blog post) took me out to a tool room today in order to show me some of the “fishing tools” they use to recover materials from inside of holes. I’m interested because we hope to come back here and fish out our experiments from Hole 395A.
Basically these look like long rods with a series of offset barbs near the terminal end – like fish hooks – that you stick in borehole to retrieve whatever is down there. In this case, some very precious experiments! We are cautiously optimistic after discussions with the drillers that we can actually do this successfully. Just have to bide our time for a few years until the time is ripe….