Sampling up a Storm
I’m writing from where L’Atalante is currently parked, 18S 170W, right in the middle of a giant, anomalously high sea surface chlorophyll patch. Such a high concentration of chlorophyll—a pigment that helps photosynthetic organisms harvest energy from sunlight, and the one that’s responsible for the green color of plants—can mean but one thing in the ocean: a phytoplankton bloom.
The satellite images of this bloom are stunning: a screaming red splotch surrounded by blue, the desert color of the ocean, which is used to denote regions with very little chlorophyll. Paths of red snake out from the center of the patch and shed light on the physics that drives this phenomenon. A physical oceanographer aboard L’Atalante described it to me as two adjacent eddies, enormous whirlpools of water that stir up nutrients and drive the productivity of phytoplankton.
The satellite reconstruction of this chlorophyll patch is so popping that I expected a noticeable change in the water when we arrived. I just took a stroll around the deck of the ship, and to be honest, to the naked eye the water looks just as crystalline blue as it did outside the patch. I love this about the ocean: it’s an expert at keeping secrets. It forces us to think outside the box—or rather, outside the boat—on a bigger scale than human perspective in order to figure out what’s going on. Because I’m a microbial oceanographer, at the same time I think about processes at the other extreme of the size spectrum, which genes are differentially turned on or off by the microbes in this patch, and I start to get dizzy.
Dizziness has been a common theme this past week on the South Pacific. As if metaphysical thoughts about the size scales of ocean processes weren’t enough to make me queasy, Tropical Cyclone Pam was there to rattle things up as well. Pam is such a nice, innocuous moniker, but this storm is so vicious authorities have renamed her The Monster. It’s the largest to hit the South Pacific in recorded history, and we’ve sailed on its outskirts for the past week and a half.
The captain skillfully navigated us away from danger; the worst we on L’Atalante faced were long, rolling waves and pounding rain—nothing compared to the devastation endured by Pacific nations like New Caledonia and Vanuatu. Our escape path sent us across the International Date Line a day early, literally sending us back in time to flee The Monster. As a result, I had two Thursdays this week. Had we crossed the Date Line at the originally scheduled time, Friday the 13th would have repeated. I’m not superstitious, but while floating in the middle of the largest ocean on the planet during a tropical cyclone, two 13ths is a chance I’m glad we didn’t take.
Today the physicists have the run of the ship as they deploy sensors that characterize the physical structure of this region. This means us biologists have the day off. It’s a welcome respite, because for 15 hours yesterday we conducted a high frequency biological survey as we cruised from one side of the patch to another. It was a sampling frenzy: 12 people queued up to take seawater from one spigot every 20 minutes. Everyone else needed maybe half a liter. In the Dyhrman Lab, we think big (about the smallest critters, that is). I hobbled up to the spigot each time with three 20 L carboys, explaining in all the French I could muster, “I need this much for the genes! For the genes!”
If you’d like to read more about what’s happening on the OUTPACE 2015 cruise, check out the blog of another oceanographer on board L’Atalante, Marcus Stenegren, a graduate student at Stockholm University in Sweden. Totally worth your click if you want to see action shots of me, with a mustache, hopping between blocks of wood during the “OUTPACE Olympics.”
Finally, if you’re still interested in seeing more—and if you want to brush up on your French—check out the video features of OUTPACE happenings, produced by the co-chief scientist, Sophie Bonnet.