In the wee hours of the morning, when the sun has dipped behind the horizon line for a few hours (it is never truly dark) the MOCNESS completes her first tow of the research cruise. It is with anticipation that I wait for the first net to raise out of the water. Twenty-four hours of waiting finally yields a reward.
The day didn’t start off in such high spirits. A series of delays, mishaps and unfortunate circumstances delayed our first real scientific catch. You quickly learn this is the rule in oceanography, not the exception.
El Nino seems to be causing a series of unpredictable and extreme weather across the globe. Here on the Western Antarctic Peninsula it has created ice, lots of ice. On some mornings the ocean surface almost completely covered. Such was the case on the morning before our first MOCNESS tow. The great thing about the Gould is that its hull is reinforced to slice through the ice floats, but in heavy ice that resistance adds a bit of extra time to our travel.
Preparing to launch the mighty MOCNESS soon revealed a series of issues with the device itself. Data collection from the MOCNESS relies on a series of electrical sensors to determine depth, temperature, the angle at which the net hangs, etc. On our first attempt the GPS was not communicating with our computers on board. Not a good start. The sensor that determined net angle, too was misbehaving. It consistently read that the MOCNESS was sitting perpendicular when in reality it was lying flat on the deck. A few set backs but nothing the Electronic Techs couldn’t handle. But of course, once we fixed those two issues the flow meter was busted.
The purpose of the MOCNESS is to run one tow in the morning and one tow at night so we can then compare the difference in types and amounts of zooplankton. Zooplankton travel to the surface at night to feed on phytoplankton. This daily migration called diel vertical migration is a safety precaution. Better to feed in the dark when your predators can’t see you.
By the time we fixed the MOCNESS we missed our window.
By domino effect I eventually spent 43 hours working on three of sleep. By the end of the second day it was almost a challenge. Can we finish our work while resisting the urge to nod off? In total, after the first failed tow, we accomplished six tows in over the next two days, including a successful second try at our first MOCNESS. Each time we haul a cod-end on board we opened the top to reveal hundreds of krill and other critters zipping around.
Stay tuned for more on what we caught!