This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American
A while back I wrote about how the CTD was the most important instrument on board. Well, it turns out, I was wrong. Here's the most important instrument: Ena, the coffee maker. And it's owned by Jack DiTullio. He's another one of the principal investigators on board
Pigments, vitamins and compounds oh my!
When he's not dutifully caring for his fancy coffee machine, Jack is a professor at the College of Charleston, in South Carolina. His research on board focuses mainly on the physiology of the coccolithophores, particularly how and why they produce this one specific compound called DMSP (which stands for dimethylsulfoniopropionate -- that word's not rolling off my tongue just yet).
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From what I've gathered here, DMSP is like a magical compound. Cells make it when they're stressed, and they use it to regulate osmosis. When the cells are eaten by predators, DMSP is turned into DMS (dimethyl sulfide), which is a gas that leaks from the ocean into the atmosphere. When you go to the beach, you know that smell of the ocean? That's DMS. And DMS molecules are important parts of the nucleus around which clouds form.
So, in theory, the more coccolithophores who die, the more DMS goes up into the atmosphere, and the more clouds form. Which means that the life and death of coccolithophores like Ehux has a lot to do with how many clouds cover the ocean, which can change how reflective the Earth is. The more clouds, the less sunlight reaches the Earth, which means the less warm the Earth gets. And it seems like that change in temperature could in turn effect Ehux.
One of Jack's graduate students, Jacob Kendrick, stumbled upon this potential temperature effect essentially by accident. He was trying to culture Ehux in the lab in Charleston, and he successfully grew them. But when he introduced them to the virus, his Ehux simply weren't dying. The virus wasn't infecting them, and he couldn't figure out why. So he called up Liti Haramaty - a researcher in Kay Bidle's lab - to see how they got their infections to work. Turns out the only difference between them was the temperature at which they were growing their Ehux. Jacob's cells were grown at 22 degrees, and Liti's were grown at 18 degrees. That three degree change, seemed to make all the difference. Cells living in warmer water weren't susceptible to the virus, weren't dying and breaking down, and thus weren't releasing DMS into the atmosphere.
The idea is kind of like the Gaia hypothesis: if the Earth is out of balance, say it's too hot or too cold or there's too much of a certain compound, it will naturally correct itself in some way by decreasing or increasing the temperature, or developing a way to break down the excess compound. This is a controversial hypothesis, and Jack isn't saying that the Earth has some sort of collective mind of its own. But it is an example of a feedback loop, he says.
It works like this. The warmer the water gets, the less susceptible Ehux is to viruses. The less they're infected by viruses, the more they're eaten by grazers. The more they're eaten by predators, the more DMS is released. The more DMS is released, the more clouds there are, and more clouds means the ocean gets cooler.
So on the ship, Jack and his team are trying to figure out just how many Ehux are being eaten - and thus releasing DMS into the atmosphere. To do that, they're collecting samples to count the Ehux and their predators, and to determine how that relationship affects the amount of DMS leaking out into the water and atmosphere.
Jack has a few students and other researchers with him. Rachel Stevens is an undergraduate in his lab, and is helping out with the filtering of the thousands of samples they're taking. Jacob Kendrick - the one who found the temperature effect - is doing his masters degree with Jack, and he's using a high tech sorting flow cytometer that can take a sample and sort its different parts into different tubes. So, for example, he can tell the machine to process a sample and take out things of certain sizes or optical properties, like Ehux or viruses. He then hands those different groups over to other teams doing genetic analysis. Jack's last colleague on board is Peter Lee, who (among other things) is looking at the effect of vitamin B12 on Ehux.
The man behind the plankton
Born in Italy and raised in Boston, Jack is a games guy. He likes sports: The Red Sox, Italia Futbol, Patriots football. And he's good at playing games too, from Cribbage to Backgammon.
He's also a food guy. Where most of us stand in the mess deck trying to figure out which of the seven dinner choices we should have, Jack just tries them all. You can tell what's for dinner when you walk into the mess deck, because Jack is nearly always sitting in the same seat, right by the door, eating everything the kitchen created that night.
But if there are two things you should know about Jack DiTullio, it's not to mess with Ena, and not to remind him that he should have bet on Giacomo in the 2005 Kentucky Derby.
During this trip, I’ll be answering your questions about the science, this ship, and life onboard. Want to know how we search for plankton, why we’re here, or what the food is like? Just ask me! And if you’re wondering how I got here, check out the groups that made this adventure possible: Mind Open Media and COSEE NOW.
Previously in this series:
All Aboard: how you can be a part of our research blog
You wanted to know: what are these phytoplankton?
You wanted to know: what am I bringing to sea?
Greetings from Ponta Delgada! We set sail tomorrow.
Steaming North: how the scientists are trying to find plankton
The superstar sensor: what is a CTD?
Status Update: Day 3 at the Cyclonic Eddy
You wanted to know: what is this virus that infects the phytoplankton (Part One)
You wanted to know: what is this virus that infects the phytoplankton (Part Two)
Plankton hunting: Part art, Part science
You wanted to know: what’s the food like on board?
Jumborizing: a brief history of the R/V Knorr
On the importance of names. Or, “are we at the hump or the hole?”
Arts and crafts day on the Knorr
On the importance of names, part two. What’s the difference between a boat and a ship?
How to stay sane on a ship in the middle of the ocean
A graphical representation of the cruise so far
You wanted to know: who are these scientists? Introducing: Kay Bidle