Muddy Megacorer Monday

I rise early, eager to see what the megacorer has returned to the surface. Unfortunately, the winch’s wire became stuck last night, and no sediment was retrieved. But the megacorer has already been redeployed and is on its way back to the seafloor over 2 miles below us. It’s another morning of monitor-checking, counting down the meters during its three-hour journey (one and a half hours each way) back to the surface.

When it is due back, we slip into our safety gear—hard hat, steel toed boots, and flotation jackets—and head out to the aft deck. Standing well back under cover, we watch as the marine technicians await the megacorer’s arrival. The seas are rising, and the occasional wave breaks across the rolling deck.

The marine technicians capture the megacorer, which is swinging wildly due to the heaving seas, with ropes and carefully reign it in, lower it, and secure it on a base on deck.

When the megacorer rises… success!

Six tubes are filled or nearly filled with sediment from the seafloor far below us. The marine technicians capture the megacorer, which is swinging wildly due to the heaving seas, with ropes and carefully reign it in, lower it, and secure it on a base on deck. When it is safely onboard, the science team swoops in. Pairs work to remove the tubes without losing any mud the way we have been taught, place them in the crate, and carry them into the nearby aquarium room for processing.

First, we record the number of each tube and its general appearance. We measure the depth of the mud and of any seawater on top and take photos of each tube. Then we siphon off the seawater above the mud. Sometimes, scientists will keep this water for analysis, but if that isn’t relevant to our experiments, we discard it.

Next comes sectioning the cores. The tube is placed on an extruder and pushed down until the mud begins to emerge from the top of the tube.

We measure 1-2-centimeter-thick slices and slice them off, trimming off the edges that have been smeared along the tube walls (so as to avoid contamination by mud of different age).

We store each section in a bag labelled with, among other things, the depth of the section in the core. Joe, one of the marine technicians, remarks how much like chocolate it looks, and I agree. One can easily imagine we’re slicing through round chocolate mousse cake. Nevertheless, this is a thick clay-like mud, perhaps up to several thousand years old, and we expect it to be full of diatom skeletons.

Meanwhile, the ship is on its way to sampling station two, heading north along 170 degrees west. The seas have picked up today, and we expect 9 to 11 foot waves or more. As we pause to eat lunch in the galley, which is in the ship’s bow, waves crash over the portholes. Our non-slip placemats are back on the tables—a harbinger of the seas we’re heading into. The floor falls away with a sickening motion and then presses up against us, as if we’re in a rollercoaster reaching the zenith of a hill, plummeting into each valley, before it raises us to temporary weightlessness once more. It’s a ride that never ends, one you can’t get off.

I wondered how scientists work on a constantly moving surface… Well, now I know. The answer is “very carefully,” constantly balancing, bracing against the next big wave and the ever-rolling motion of the ship. It becomes second nature after a while, and we are only caught off-balance when a particularly big wave rolls through, but it is tiring work requiring strength of body, mind, and purpose. A good sense of humor helps, too, and there are plenty of smiles and jokes as we slice, scrape, and bag this ancient sediment. When we are done, we are muddy, tired, hungry, and happy. This is thoroughly satisfying work.