IODP Third Report –Arriving on site
The JOIDES Resolution and our scientist-at-sea, PhD student Steffen Jorgensen, have arrived at the first site.
Hovedinnhold
Jorgensen is participating in IODP’s Expedition 336 (International Ocean Drilling Program). On 21 September he reported that …
“We are now 1000 nautical miles north-east from Barbados and literally as far from anything as you can get in the Atlantic. Midnight we arrived at our location over site 395.”
He explains the routines involved at being on-site at a previously drilled hole. Drilling a new hole takes much longer and the ship can be on-site for some weeks.
Measurement routines
“The first thing they do is to throw a beacon overboard that will sink to the seafloor. That along with the GPS will keep the ship in position, by correcting using the six thrusters that are now lowered do that. These are guided by the GPS and the signal from the beacon.
When the ship is position the rig and drilling people start to do their job. That means lowering pipe after pipe down the “moon pool”, which is a hole through the middle of the ship (learn more about the ship and the moon pool).The drilling equipment operates here where it is protected from exterior ocean surface conditions (such as rough waves due to bad weather). Each pipe section is 30 meters long and is lowered down the hole at an incredible speed. Before it disappears in the sea it is connected to 30 new meters of pipe. At the moment there are 3500 meters of pipe hanging under our ship. That pipe will be extended a further 900 meters until it reached the seafloor.
The next thing that will happened is that they will try to locate the re-entry cone to hole 395A. For this purpose they lower a camera down the outside of the pipes. As one could imagine it might not be so easy find this in the complete darkness 4400 meters below us. The diameter of the re-entry cone is approximately 3 meters!
When we find it we will go through the re-entry cone and connect the top (or the bottom you might say) of our pipe to the old installation and start to retrieve the old CORK installation. The CORK contains pressure and temperature tools that have been logging data for many years. In addition some of the microbiogists will sample from the steel string the CORK installation is attached to, in order to see what kind of organisms are living there.
After all this has been done (if everything goes according to plan), at around midnight, we will start the logging of the hole. That means that we will run a bunch of different instruments down inside our pipes from the ship and further down in the old 395 hole that we are attached to. Inside the old hole these instruments will start to measure different geochemical and geophysical parameters while it is being lowered. This year is especially exiting because a new instrument to estimate biomass has been developed. It operates by using UV light and reflection to estimate biomass. This has never been done before so there are many unknowns and things that potentially could go wrong, but we microbiologists are excited!
After the logging, which they do twice (up/down up/down) all the way down at 600 meters below seafloor where the hole stops, a new CORK system will be deployed (more about this later!
Ship-board routines
Well enough of this boring scientific stuff and let me tell a bit about ship life. At this point I am getting up at 0900, eat, write mails and work on papers, eat, meetings, work out in the gym, eat, write mails and work on papers, night snack (if you stay up until midnight there is a new hot meal J), sleep. I know that doesn’t sound much but I can tell you that the day just vanishes into thin air.
So far there is not much wildlife, a couple of flying fish and a lonely seabird is all that I can report. That will hopefully change after the fish get the sniff of us while we are at the same place for almost a week.
Weather-wise it has been nice and calm (almost) 27 degrees C for both the air and water. There is a new hurricane building up to the south off us, but that front will most likely go due west and not affect us (except some moderate wind), so nothing to worry about.
That’s all until next time!”
Have a question? Send it to Steffen!
Links relating to the cruise:
