The Sun helped us recently celebrate the second-to-last mooring of our expedition. Lots of us went outside to enjoy a little bit of sunshine along with the amazing sight of lowering instruments down 2,700meters (more than 1.5miles) into the ocean. Here’s more about this outrageously awesome piece of science and engineering.
The photo shows the diagram of this M9 mooring. This diagram has been well-used, as you can see from the notes scribbled all over it (most of which are serial numbers of the components). This mooring was deployed in a location where the ocean floor has a pretty steep slope, and a couple things were adjusted to the whole structure to account for this. A heavier-than-usual anchor was lowered down as the base of the mooring (it’s about 850kg in water), and an extra “buoyancy support” element (the square yellow component in the diagram) will help raise the mooring out of the water when another expedition returns to retrieve it.
The two yellow cylinders in the diagram, between the anchor and the extra buoyancy support, are the “release assembly.” You can see the bottom of these two cylinders are joined by a “v” shaped link and ring. When another expedition returns to retrieve the mooring, they will “speak” to the release assembly with an acoustic signal, and one of those releases (the other is there as a back-up) will detach. The anchor will remain at the bottom, but the rest of the mooring cable and instruments will be lifted up out of the water, aided by the buoyancy components.
There are five different CTD (conductivity, temperature, depth) instruments on the mooring, at various depths, which will take these ongoing measurements of the water. There are also two “upward-looking” ADCPs (Acoustic Doppler Current Profiler), at roughly 450meters deep and 50meters deep, each of which will measure water currents between their location and the surface. The instruments in the diagram just below the largest yellow buoyancy sphere (the ISUS and ODO) will be taking measurements of nitrates and dissolved oxygen in the water, which will help scientists trace water masses throughout the Arctic. (We have put these instruments on three moorings at three different locations, all of which will take ongoing measurements until they are retrieved during a future expedition – and we have also been taking measurements of oxygen and nitrates throughout this expedition, every time we do a CTD cast). There is also an upward-looking sonar near the top of the mooring, which measures ice-depth at the surface.
Just knowing our position when we deploy this mooring (82°N latitude, 97°E longitude) is not enough to locate it to retrieve it in the future. The ocean is huge (not to mention the fact that the area is sometimes ice-covered). Near the top of the mooring, still almost 50meters down, the location transponder will be able to send and receive signal from a ship, allowing the future expedition to more precisely locate and retrieve the mooring. Can you see why I described above the whole mooring process as “outrageously awesome?”
Hey Lindsay I realized the m9 mooring is a complicated device, or at least this is the way it seems judging from the drawing. How do you prevent failures when using a device like this ? And what are some of the common complications?
Hi Rochae, wow that is a great technical question. There are a couple things that we have to consider and plan for when dealing with moorings. The first thing is that you can double-up on equipment and instruments, so that if one doesn’t work for whatever reason, the other still will. For example, we will need to retrieve the mooring on a future expedition. So the release assembly that I mentioned has two of those yellow cylinders at the bottom for this reason. If you look back at the picture, the two cylinders are connected to each other through a ring and a chain. So if one of them doesn’t release when we tell it to, the other one will – and by releasing that chain, both of them can safely come up to the surface, along with the rest of the mooring. The other thing is the waves and weather. You need to keep the cable as vertical as possible while deploying the mooring, and lots of waves and wind can put tension on the cable and pull it nearer the ship’s propellers. I’ll mention one more thing – the ice that we’re here to study can actually stop us from retrieving the mooring, if the ice at that location is too thick the next time the ship returns!
how often does it snow by you guys and girls?
Hi Angel, it’s cloudy almost all the time, but it has only snowed a few times during the expedition. It is enough to make the ship’s deck pretty icy and slippery, but there are not mounds of it – there was enough to make a miniature snow-man and snow-polar bear though!
Has your life changed after you’ve started the expedition?
Hi Jessica, that is a big question. I think my life will have changed due to this expedition, because I think something like this gives you a whole new perspective on the world. I have learned so much, and it’s kind of like proof that everything on Earth is connected through the oceans and atmosphere, and also that many areas of science are all involved in the field of climate. It makes me hope even more that we can all make good decisions about the climate for the future’s sake. Plus I will have stories to tell for a long time to come!
what are those red/orange balls ,and what do u use them for
Hi Kaderrius, those orange spheres will actually be placed on top of the mooring line which runs from the seafloor to about 50meters from the surface. It is part of the location transponder which will transmit a signal with sonar to scientists when they return on the next expedition to retrieve the mooring from the water.
Hello my name is shantrell wright im in ms.gilbert class.. Heres my question In the Mediterranean they use atool called RAFOS for measuring. Do you use the RAFOS tool as well???
Hi Shantrell, that is a good question. I checked with a scientist onboard, and she explained that RAFOS is used for acoustic navigational purposes, so we have not used that on this expedition, when we are doing a lot of studying water samples using the CTD instrument for example (which measures conductivity, temperature, and depth). But RAFOS has been used before in the Fram Strait, which is the “pathway” between the Arctic and the Atlantic.
how much effect do you think the change between the climate now to where you go once the expedition ends will be?
Hi Vilanea, climate actually has a bigger definition (literally), because it refers to things happening over long time scales (years or decades or even more) and big distances (like hundreds of miles or more). So we won’t see changes in the climate during this 5 week expedition. But if you’re referring to the difference in the weather between the Arctic and the port where we will end the expedition, it will probably be pretty different! We have had below freezing temperature the whole time, and now we will go back to maybe 60°F during the day in Norway. And it will probably be sunnier too! 🙂