Dive and Discover : Expedition 10 : Antarctica : Day 13

Here we are, floating on an ocean of salps. We find them every time we tow a net or take a dive. “For the first time,” Pat Kremer said, “we have enough salps to do every experiment we want to do.”

What is it, exactly, that we do with our days and nights?

The Bongo Boys
Byron Pedler and Jeff Mercer are the “bongo boys.” Bongo tows, conducted by a dedicated team, quickly reveal if there are salps in surface waters.

They fasten the net to the cable, and tie off the narrow end of the net with string. There’s a flow meter on the net, which records the amount of water it goes through. Either Byron or Jeff tosses in the net, and the other tosses the weight that carries it down. When it comes up, capturing plankton, they take the catch to the wet lab. “It’s easy,” said Jeff, “But I’d rather be diving.”

The Salp-Pickers
When the buckets arrive, Kelly, Kerri, Wally, Izzie, Brenna, Byron, and Diane swing into action. Leaning over the net catch, they pick out every salp in the sample. They lay them out on dishes labeled with the net they came from, arranged by sizes, and carry them into the hydrolab for measuring.

The (Dis-)Assembly Line
Every last salp in the sample gets measured (there could be hundreds). Lena, Jun, and Brennan do this job, working with a partner who writes down each number. They then remove the salps’ guts (the stomach and intestines, which can be as small as a sesame seed in small salps, and as large as a pea in large ones.) Rapidly they transfer the guts to foil packets and freeze them—thousands of foil packets.

The Test-tubers
Izzie Williams is a test-tube reader, along with Wally, Brenna, and Diane “It’s the tyranny of the tubes,” Izzie said, because 500 test tubes are constantly being used, washed, and used again. They grind up the frozen salp guts in a test tube with a liquid (acetone). The plant pigments—colored substances in the algae the salps ate—goes into the liquid. A fluorometer is used to measure color intensity of each sample, which tells them how much pigment the sample contains.

“We extract the pigment from the food in their gut, and it’s an indicator of how much they ate,” said Jun. “We can understand when they feed, and link it to their vertical migration (going up at night and down in day) by knowing how much food is in stomachs of salps at different depths and times of day.” When, where, and how much they eat will tell us a lot about the impact salps have on the Antarctic ecosystem.

The Bongo Boys Byron Pedler and Jeff Mercer are the “bongo boys.” Bongo tows, conducted by a dedicated team, quickly reveal if there are salps in surface waters.

The Bongo Boys
Byron Pedler and Jeff Mercer are the “bongo boys.” Bongo tows, conducted by a dedicated team, quickly reveal if there are salps in surface waters.