A Scientist's Life: Andrew Barton

Marine ecologist considers diversity of plankton and their roles in ecosystems

Andrew Barton is a marine ecologist with a joint appointment at the University of California San Diego’s Scripps Institution of Oceanography and Division of Biological Sciences. He received his PhD in climate physics and chemistry from the Massachusetts Institute of Technology in 2011, and was a National Science Foundation International Research Postdoctoral Fellow hosted jointly between Duke University and the University of Liverpool in the United Kingdom. He joined the UC San Diego faculty in 2016.

explorations now: What do you do for a living?

Andrew Barton: I'm an assistant professor at the University of California San Diego with a joint appointment between the Section of Ecology, Behavior and Evolution and Scripps Institution of Oceanography. A big part of my job is education, and another key part is research.

Education includes teaching courses, but also mentoring early-career, up-and-coming scientists, which I really enjoy. It’s partly the traditional teaching of classes in a lecture hall or lab setting, but also includes one-on-one interactions with young scientists, mentoring students in their own research, helping them formulate their own problems, set up their own experiments, and develop their own models. It's something that I find really rewarding. Each time I work with a student I learn something new.

Research is where you push forward a research agenda and try to make progress on a particular question or field. I'm a marine ecologist. I study marine plankton, which includes phytoplankton, photosynthetic marine microbes living in the surface ocean, up to organisms as large as krill, which are crustaceans that some whales famously feed on.

en: Why are marine phytoplankton important?

AB: Marine phytoplankton are incredibly important globally, even though they're individually tiny. Marine ecosystems depend critically on marine phytoplankton—fish, seabirds, and marine mammals all ultimately gain their energy from photosynthetic phytoplankton in the ocean. But they are also really important for biogeochemical cycles of elements like carbon, nitrogen, phosphorous, and oxygen.

For example, phytoplankton build their bodies to a large degree out of carbon. So when we emit greenhouse gases, some of that carbon ultimately ends up in phytoplankton in the ocean surface and then a fraction of that carbon eventually sinks with their dead and decaying bodies. Without phytoplankton in the ocean, the biogeochemical cycles of carbon, nitrogen, phosphorus, and other elements would be very different, and in fact our climate on Earth would be quite different than it is today.

en: What tools do you use for your research?

AB: I use a combination of observations and models. I think they're very complementary, and there is a strong two-way interaction between these perspectives. Observations can be made by going out to sea, collecting plankton, and then looking at them under a microscope, or you can also do careful studies in a laboratory setting. Models are numerical simulations where, in many cases, you try to understand what you've observed. For example, if at the Scripps Pier we always see particular plankton growing at certain times of year, we can use a model to try to understand why. 

en: What are the big questions in your field?

AB: One of the main questions that I ask, and that other people are interested in, is why are there so many species of plankton and what roles do they play. We find that different areas of the ocean sustain different numbers of species, and we don't understand why that is yet, and we don't understand the impact of that diversity on fisheries and biogeochemical cycles.

I also like to think about general organizing principles of ecology – not just what happens at one particular spot, or two particular spots, but if you look at many, many places around the globe, what tends to organize all those systems? What conditions or properties do they have in common?

I think for land plants, and land animals, we have a fairly good intuition about where they live and why. For trees and birds, you can pick up a guidebook, and see a map about where they live, and the common observer can see these things. It's far more difficult in the ocean, because it's difficult to go to sea, and the microorganisms are hard to collect and count. So we don't yet have that sense about where planktonic organisms live and why. I want to build that appreciation of planktonic organisms in their natural environment.

en: Why did you pick Scripps as a place to work?

AB: I think the University of California San Diego and Scripps are globally unique places to work, because you have so many experts in different fields. My research is strongly interdisciplinary. I work with physical oceanographers, biologists, ecologists, even chemists, and being here I have the ability to draw upon expertise across all of these different disciplines, and work with people who are world-leading experts in different areas. My skill is trying to integrate these different areas to tackle ecological challenges and questions with global implications.

I think a great example of interdisciplinary research at Scripps is a collaboration I’m working on with (research oceanographer) Jules Jaffe and (biological oceanographer) Peter Franks. Peter Franks has a background in physical oceanography and biophysical interactions in the plankton, and Jules Jaffe is interested in developing new technologies for monitoring ocean biota. 

We want to understand the population dynamics of marine phytoplankton by using high-tech automated instruments at the Scripps Pier and possibly elsewhere in the future. We want to know when populations rise, and when they fall, and we want to know why. We'll take these observations from our waters and couple them with observations about the environmental conditions, and then develop models to try to synthesize the ‘why.’ By bridging these disciplines hopefully we'll be able to see new ecological dynamics and interpret the patterns we see in a new way.

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