CCE-LTER (RAPID 2016)

Ecosystem Responses to El Niño

Date: April 30, 2016

When life hands you lemons, make SKrillEx 3.

A few days ago we were nearshore and a storm was rolling in. The weather was so bad that the captain said we had to stay nearshore for an extra day before beginning the two-day steam out to our next study location.  It felt like we were going to waste an entire day, except to Cat Nickels of the Ohman Lab.

For the last two summers, Cat has carefully planned two student cruises in these nearshore waters for her PhD thesis, in a place called Nine Mile Bank. Nine Mile Bank (nine nautical miles offshore, if you couldn’t guess) is a feeding ground for blue whales during the summer, but she has seen blues, fins, and the occasional humpback there.  Cat’s thesis focuses on whale-krill interactions, and she is interested if the topography of the bank affects krill aggregations and whale feeding patterns. SKrillEx 1 (Student Krill Expedition) took place in the summer of 2014 and took months to plan; it had students from multiple labs working on chemistry, benthic ecology, microbiology, microbial ecology, and microplastics. SKrillEx 2 (summer 2015) also took months to plan and revisited the same site to ask similar questions.

SKrillEx 3, as we came to call this day at sea, was planned by Cat in 20 minutes. When the captain said we had to stay nearshore, Mark Ohman asked if we could go to Nine Mile Bank. Soon Cat was plotting coordinates for an MVP transect and an all-night bongo tow transect like we had done the last two summers. This pre-blue whale season third replicate may end up being extremely useful for Cat’s thesis and it was all because of stormy seas and quick thinking by Mark and Cat.

The all-girl night shift on the bongo:

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Cups! Cups! Cups!

It is that time of the cruise for the sacred maritime tradition of….shrinking styrofoam cups.

I have no idea who figured out this odd pastime at sea, but the reasoning goes like this: As you move deeper into the ocean, pressure increases due to the weight of the water above you.  All of our equipment has to be rigorously pressure-tested, and is all graded to only go to a certain depth.

Styrofoam is polystyrene plastic that is formed by blowing air into  the plastic during creation.  So, what happens when you attach Styrofoam to said equipment and send it to the bottom of the sea? The increasing pressure with depth pushes the air out of the plastic, and you are left with condensed Styrofoam, sans air. In simpler terms, the pressure causes everything foam to shrink, while the metal equipment, not comprised of air, comes back up in the same shape.

Anything you draw on the cups shrinks with them. We sent down one bag of decorated foam cups, wig heads, and cubes from the science party on board, and two bags from a local San Diego middle school.

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First Cat, Maitreyi, Belli and Ali prepared all the cups by filling them with paper towels and tape to maintain their shape, and then zip tying the laundry bags closed so we didn’t lose any to the ocean.

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Then the Science Techs kindly zip tied them to the CTD for the deepest cast of the cruise. The cups went to 3000 m!

The cups came back a little smaller (note the difference in bag size):

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The most impressive part are the before and after shots:

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My head shrunk a lot at 3000 m!