“The first class is an eye-opening one because I say, we’re going to learn why the oceans are salty. We’re going to learn why the water is blue and why the oceans move the way they do,” said Benitez-Nelson, Distinguished Professor in Marine Science at the University of South Carolina in Columbia.
Then, to help illustrate how oceans behave, students grab each other's hands and move like seismic P-waves and S-waves, or they pretend they are water molecules and have to bond to each other.
“We focus on concepts and why things work the way they do. They draw, they move themselves, we just do a lot of things that make them think conceptually about what they are doing and why it is important. And it's a tough transition. A lot of them are like, ‘Can’t I just memorize the answer?’” she laughed.
Benitez-Nelson says plenty of smart kids enter college having mastered high school biology, chemistry, and physics, but they have not had the opportunity to pull it all together. Midway through her class, though, concepts like large-scale ocean circulation and atmospheric convection all start making sense.
The passion and intensity that Benitez-Nelson brings to the classroom continues the guidance shown to her as an undergraduate at the University of Washington, where she was breezing through math and chemistry classes with no clear career path -- understandable, since she started college at age 13. After acing numerous aptitude tests in middle school, she enrolled in the university's experimental program. She says it was the best of both worlds for her; college courses that challenged her, plus the ability to continue to play high school sports with her friends.
One of her professors asked if she had ever thought about oceanography. When he told her she could do chemistry on a research ship, she remembers thinking, “That's a job?”
She soon landed a research position in another professor’s lab, and in no time, she was doing chemistry on the high seas.
“My first cruise was off Mazatlan, Mexico. We deployed Niskin [water sampling] bottles, we did oxygen measurements, and they did some coring. I was the chemist. I was a flunkey, but I was a chemist flunkey! It was looking at nitrogen cycling, essentially, trying to understand how low oxygen systems influenced the biogeochemistry in the water,” she said.
Today, Benitez-Nelson enjoys numerous awards and accolades both for her bold and inspiring teaching, and for her research into understanding the ocean’s role in climate change.
Her life's work uses a wide array of space and oceangoing tools, as well as traditional physical chemistry. She uses radioactive isotopes to trace carbon and phosphorus in the ocean, studying how these elements are influenced by natural and human activity.
“I’m really interested in how material makes its way from the surface to the deep oceans; how particles get transported, and kind of the cycling that forms those particles and makes them get down. So this has implications for understanding not just carbon cycling and sequestration, but things like mercury transfer, trace metal contaminants, and nutrient cycling in general,” she said.
She says a combination of satellite imagery, and ever more precise sensors on autonomous underwater vehicles are helping to take some of the guesswork out of where to go, and what to look for during a research cruise.
“So all these instrumentations, these satellite launches, help us look at ocean color, and ocean salinity. It’s rapidly revolutionized our view of the oceans and how variable they are. Now we are measuring atoms, we are measuring bonds at levels that we just couldn't do even five years ago. So combined with our knowledge of the genetics of all the organisms that are out there, the genes that they are upregulating -- doing things that we never knew organisms could do -- I guess I’m overwhelmed there’s so much exciting stuff going on right now,” she said.
One way the oceans might help moderate global climate change is by removing carbon dioxide from the atmosphere; a process called the biological pump. It’s one process that leads to long-term carbon storage in the deep ocean.
“So we know that the biological pump has played a pretty big role in our atmospheric carbon dioxide levels. We estimate that carbon dioxide might be 150-200 parts per million higher than it would be if it weren’t for this biological activity that happens in the ocean. So that's one of the reasons we want to study it to try to understand,” she said.
Benitez-Nelson compares the search for answers in our vast oceans to the exploration of the Amazon for drug cures.
“There is so much out there. You don't want to destroy it because you might find that next super vaccine. I feel like that's where we’re at with the oceans. There’s so much that we don't know, we just don't know where to start.... There might be drugs that are cures for cancer, or there might be organisms that show us novel ways of building materials,” she said.
Her next research voyage is to Madagascar, where she'll do an exploratory sampling of groundwater. It will be a collaborative effort to look at groundwater, nutrients, and how those nutrients influence coastal regions. She will also be looking at how saltwater recirculates and gets pumped back out into the coastal ocean and what happens when it releases all these varieties of elements and nutrients.
As is often the case in the field, she expects a remote work site.
“I’m bringing car batteries, duct tape, and tubing. You can get a lot done with a vacuum pump, duct tape, and tubing,” she said.
Science at sea can also have some benefits.
“I have rewired my bathroom, replaced things in my car, (and) fixed my washer and dryer. Because, if I can do this in the middle of the sea, I can certainly do it in my home with the hardware store down the street!”
Read more at The American Association for the Advancement of Science.