FROM THE FIELD
Wide Ocean, Tiny Creatures

Trichodesmium is Everywhere!

by |March 5, 2015

We have completed the first two stations of the OUTPACE cruise and we are steaming to Station 3. By noon tomorrow we should be in the center of an eddy that our colleagues back on dry land have used satellite data to identify. Apparently they are detecting very high chlorophyll in the center of the eddy, which should make for good sampling.

Trichodesmium is everywhere out here. I just looked out of the porthole next to the desk in my cabin, and a giant bloom was floating by on the surface of the waves. Filaments of the cyanobacterium Trichodesmium clump together and form little colonies about the size of an eyelash. When we’re on station, Andreas and I fish for colonies using a special net that we tow up and down through the water column to concentrate thousands of liters of water’s worth of biomass. It’s grueling work—I have blisters on my hands and my biceps are sore…but it makes me feel like I’m earning the five-course French meals served on this ship.

Once we’ve fished for colonies, Andi and I individually pluck out Trichodesmium colonies from amidst the other organisms that were concentrated during the tow and rinse them twice in sterile filtered seawater to remove all but the closely associated symbiotic microbes that colonize Trichodesmium. This is grueling work too, but for a very different reason than towing a net. Imagine using a tiny pipette to grab things the size of eyelashes out of water while rocking side to side on a moving ship in 90 degree Fahrenheit weather. Come visit me in the lab at Lamont and I’ll let you try and pick some Tricho—it’s hard even when the ground isn’t moving beneath you.

Sunset over the South Pacific ocean at the end of Station One.

Sunset over the South Pacific ocean at the end of Station 1.

So far, we’ve set up experiments to look at how nutrient uptake changes when we add different microbial communication molecules to the Trichodesmium colonies we’ve plucked, and of course we’ve taken samples so I can look at the molecular underpinnings of these physiological changes. The first two stations have been pretty successful. The ship is stable enough that I haven’t had to take any Dramamine, and really, the food is incredible. I woke up to sample at 5 a.m. yesterday, buoyed by the smell of freshly baked croissants.

Now that we’ve got our sea legs, I think we’re ready for the big kahuna, so bring on whatever’s happening in that eddy!

Follow @kylefrischkorn and the @DyhrmanLab on Twitter for more frequent updates from the OUTPACE cruise.

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