armbrust e virginia

One of your recent papers described a “phytoplankton hotspot” in the Pacific Ocean. What causes a phytoplankton hotspot?
By “hotspot” we mean an abundance of phytoplankton occurring in a spot where you have a convergence of open ocean water that meets coastal waters—it’s a transition zone, a place where we believe that the nutrients are just right: the open ocean is bringing lots of nitrogen for the phytoplankton and the coastal water is bringing lots of iron.
What we saw happening there was a large draw-down of carbon dioxide from the atmosphere. We developed an instrument that we call “SeaFlow” —an underwater flow cytometer. It taps into the seawater intake of the ship and is continuously measuring the abundance, size and pigment content of phytoplankton in surface water. And we can make those measurements on the biology while simultaneously making other chemical measurements, like nitrate, salinity, or temperature.

You lead the team that analyzed the first diatom genome. Which diatom was it and why that diatom?
The diatom was Thalassiosira pseudonana. We chose it for a number of reasons. It has a relatively small genome, and this was in the earlier days of sequencing eukaryotes, so we wanted something manageable. The genus is also a cosmopolitan one—it’s in all of the ocean basins. And the species has a long history of physiological studies, so we thought that would also be important because there would be a context to place our genome data in. It was important to me to choose an organism that had an ecological role—not simply a “lab rat,” because we imagined there would be lots of studies that would come later because we had a genome sequence.

Did anything surprise you in the genome?
It was one of the more exciting science projects I’ve been involved in. We didn’t know what to expect.  The big surprise was the diatom seemed to have properties we previously associated with plants, but there were other attributes that had previously been associated with animals. So we could see that their genomes were a sort of mix and match.

What is your lab working on these days?
We continue to work on diatoms, but after all these years I realized the diatoms don’t live in the oceans all by themselves. They live with other organisms. We’re trying to understand the interactions between diatoms and bacteria and archaea. And we’re also doing metatranscriptomics to understand how the organisms function in the environment. And we have another genome we’re working on.

Where do you see your field in 10 years?
I see us moving into a place where we have enormous amounts of data that are coming from the ocean, and we can have oceanography that interacts with multiple different disciplines. Society’s needs for the interdisciplinary skills that go along with being an oceanographer will only increase. My dream is that oceanographers will play a more and more important role in understanding environmental issues.

Are you referring to climate change?
I’m referring to all the issues our society faces, whether it’s an oil spill, increased carbon dioxide, coastal environments, or issues regarding the enormous biodiversity that’s in the ocean.

If you had to change careers today and you could do anything, what would you do?
I can’t imagine there’s a better job out there for me. It’s a really exciting time to be an oceanographer. I love being a teacher, I love being able to talk about the science. I have this one skill set that matched.

What’s your favorite science book?
Right now I’m reading a book all about giant waves. It’s for general audiences. It’s about surfing, rogue waves, and tsunamis. I teach a course in introductory oceanography, so I like to read books I think the students will be interested in.

What is something about you that most people don’t know?
I can tell you what people are always surprised to learn about me: I was raised in Texas. I lived there until I was college age and had a really heavy Texas accent when I was a kid. Now you know everything about me.