The ocean is big. We are small. These statements are obvious. But just how big, and how small? Numbers and estimates only take your brain so far, and then you have to start using analogies. Here’s one: the Mariana Trench, the deepest trench of the ocean (11km or 6.9miles deep) goes further “down” than Mount Everest (8.8km or 5.5miles high) goes “up.” Here’s another one: less people have been to the deepest parts of the ocean than have been to the Moon! By the time this expedition is over, scientists will have done over 120 CTD casts. (CTD, if you remember, stands for conductivity, temperature, depth, and is lowered, or “cast,” into the ocean with a slew of instruments that allow scientists to get data on the salinity, temperature, chemical composition, currents, etc, of the water.) You can see on the board in the ship’s hydrochemistry lab that the upcoming series of CTD casts start at 1100meters deep, and that each station gets more and more shallow. This transect, or line of stations, will provide data for the water moving through this area. And earlier in the expedition, we deployed a glider. Gliders move through the water, guided by periodic remote instructions from scientists onshore.
All of these things tell us about the ocean, and yesterday we learned from Ilona Goszczko of the Institute of Oceanology of the Polish Academy of Sciences about the “sea” of Argo floats (named after the ancient Greek ship) that are monitoring the world’s oceans as we speak. There are several kinds – if you want to know what is in the water, there are “BioGeoChem” floats. If you want to know about deep (I mean, DEEP) ocean waters, the APEX-Deep can go 6km (3.8miles) down. APEX-Electromagnetic can tell you about the motion of the ocean’s layers. And if you have something else you want to study, engineers can add sensors of your choice! To date, there are more than 4,500 floats deployed and over 1million profiles done of the oceans worldwide. However, although floats have been deployed in the periphery of the Arctic Ocean, they cannot be placed in the interior of the Arctic, because the sea ice would limit satellite communication and potentially damage the floats.
Now let’s get back to scale. This map looks like we have the oceans covered – but think about this. Imagine placing a grid over the Earth, with gridlines marking off increments of 3 degrees (1degree is 60nautical miles). The goal has been to deploy 1 float at every point on that grid, which means that even with 4500 buoys, each begin their journey separated by roughly 200miles in any direction!