Pump-mania & the Particle Master, Part 1

Yesterday, I helped Pat and Colin change the batteries in the four McLane pumps we use to collect particles from the water column. This is a complex process involving undoing, unhooking, unscrewing, and un-battery-ing, trying not to fall over as the ship pitches about in 14-foot waves, re-battery-ing, screwing, hooking, and doing-up, then testing to make sure the Outreach person has put the batteries in the right way—or something along those lines. There’s grease—7 kinds of grease, I’m told—that keeps the pumps working and the water out at 800 meters, where the pressure the deepest pump is subjected to is 80 times the pressure it experiences on dry land. Think about that. Remarkable pieces of equipment, these pumps. They each take a lot of D batteries because alkaline batteries—unlike rechargeable batteries—work in the cold of the deep-sea. D batteries must also work well under pressure, I’m thinking.

If anyone knows pumps, it’s Pat, our Pump & Particle Master, who also works well under pressure. Pat shows me how the filtering section of the pump, designed to catch particles—or marine snow—from the water is put together. McLane pumps are designed to take up to three filters of various screen sizes. We are using two: a very fine screen of 10 µm (microns or micrometers—one micron = one millionth of a meter), designed to catch very tiny particles, and one of 53 µm, designed to catch larger (but still very tiny) particles. Gloved and using sterilized forceps, Pat carefully places each screen in its holder and smooths it out. Above these is a honeycomb section of plastic design to keep out “swimmers”—such as overly curious jellyfish and the like, who might otherwise be sucked in by the sleek design and fancy workings of these strong, powerful pumps.

Now the pumps are ready to go. As the winch operator gradually lowers a cable into the sea, Pat clamps the pumps to various points on the cable, so they end up at different depths in the water column. They pump seawater and filter particles for 4 hours. (That’s why we check and/or change the batteries before we send the pumps down. It would be unfortunate if a pump ran out of power partway through its 4-hour shift.)

When Pat retrieves them 4 hours later…

…Well, you’ll have to wait to find out—Pat has been up most of the night and has received a good pummeling from the Southern Ocean in the process, so we’ll let him rest (just as soon as he processes these particles). As with the rest of the team, he works long, irregular, often absurd hours, literally tied to the ship’s deck as the wild Screaming Sixties go about their business. The sea and its particles wait for no man.