Scripps Student Spotlight: Natalie Posdaljian

PhD student examines marine mammal acoustics as a signal of greater changes in the ecosystem

Natalie Posdaljian is in her fifth year of pursuing her PhD in biological oceanography at Scripps Institution of Oceanography at the University of California San Diego. A Los Angeles native, she originally came to San Diego for her undergraduate education at UC San Diego, where she earned her bachelor’s degree in environmental systems: ecology, evolution, and behavior. Posdaljian currently works as a bioacoustician in the Scripps Acoustic Ecology Lab alongside biological oceanographer Simone Baumann-Pickering, studying marine mammals.

 

explorations now: Why did you choose to attend Scripps?

Natalie Posdaljian: When I decided it was time to go back to school for my master’s, I couldn’t imagine going anywhere but Scripps. When I was an undergraduate at UC San Diego, they didn’t have a marine biology major yet. But, I spent as much time as possible taking Scripps classes and being on campus, manifesting my return one day. Being surrounded by the world’s experts in oceanography while watching the sunset from La Jolla Shores everyday makes for an irresistible combination.

 

Scripps PhD student Natalie Posdaljian and Marine Technician Bruce Thayre work on retrieving the mooring that supports the underwater recording instrumentation.

en: What are you researching at Scripps?

NP: My research focuses on marine mammals as an indicator of ecosystem change. You can think of marine mammals as the canary in a coal mine: changes in their behavior could be indicative of greater changes in their environment. Our lab studies marine mammals by using underwater microphones to record their acoustic signatures. My specific focus is sperm whales, who are extremely vocal and found in every ocean basin, making them a good indicator for studying widespread changes. Sperm whales were nearly whaled to decimation for their extremely valuable oil in the nineteenth century. Before we can use them as indicators of ecosystem change, we must create a baseline knowledge about these animals. My research includes over 100 years of acoustic data from over 41 sites in the Pacific and Atlantic oceans, ranging from the tropics to the Arctic, aiming to understand patterns of sperm whale presence.

 

en: How did you become interested in science and your field of study?

NP: Like many undergraduates at UC San Diego, I originally wanted to pursue medicine. My sophomore year, I took a marine conservation elective that completely changed my path and inspired me to pursue marine ecology. When I graduated, I was eager to find a job that would contribute to understanding and protecting our oceans. I moved to Alaska for two years and worked as a fisheries observer, collecting data to support science, conservation, and management of U.S. marine fisheries. One of my job responsibilities was to record incidental takes and interactions of marine mammals with fishing gear and vessels. Killer whales and sperm whales would often take fish off the fishing lines—a free lunch for the animals. We would only see the whales briefly when they would come up for air, or notice the straightened hooks they would leave on the line where they took the fish from. I was supposed to take notes on how the whales were interacting with the fishing gear and vessel, but the animal was spending 95 percent of their time underwater. I knew there had to be a better way to study them outside of visual observations, which is what led me to the field of marine mammal acoustics and my lab here at Scripps.  

 

en: What’s life like as a Scripps student? Describe a typical day.

Natalie Posdaljian and Karla Garcia, a STEMulare 2021 intern, look for sperm whale clicks in acoustic data from the Western Atlantic.

NP: I spend most of the day on my computer analyzing and visualizing our acoustic data. Programming languages like MATLAB and R allow us to efficiently analyze years of acoustic data and search for patterns related to the ecology and behavior of marine mammals. Once I have results that I’m ready to share with the scientific community, I’ll spend time writing a manuscript for publication. I also mentor several undergraduate students in our lab, as well as high school students in Alaska who are working on their own research projects. A typical day includes meetings with the students to discuss their projects, help them with code, or work on figures to share their findings. 

 

en: What’s the most exciting thing about your work (in the field or in the lab)?

NP: The most exciting thing about my research is extracting patterns of marine mammal behavior or ecology from very large data sets. Our acoustic data at any given site can range from one year to one decade. Working with these long time series can be challenging. Listening to or visualizing all the sounds manually is impossible. Writing software that can take these data sets and assist you in coming to meaningful conclusions can take years to accomplish given the size of our data sets. But when you discover something in the data that you weren’t expecting, it’s exciting!

 

en: Are there any role models or mentors who have helped you along the way?

NP: I am extremely grateful for the community and mentors that I have at Scripps—especially my colleagues within my lab group. When I first came to Scripps as a master’s student, Alba Solsona Berga, who is now an assistant project scientist in our lab, took me under her wings and showed me the ropes. She supported my initial steps into acoustics and coding which I will be forever grateful for! My advisor Simone Baumann-Pickering is another one of my mentors who continues to support me throughout the PhD process, providing me with guidance and motivation. And lastly, Vanessa Scott, the director of Corporate Affiliates, Business Development, Industry Outreach and Innovation at Scripps, is another mentor who I’ve had the privilege of working with as a student fellow for almost two years. Vanessa’s passion for industry and innovation in the context of oceanography has taught me so much about what science looks like outside of academia.

 

Natalie Posdaljian participated in the GULF Listen research cruise in the summer of 2021, when the team retrieved and deployed almost 20 underwater recording devices. This involved servicing and re-deploying equipment while on the cruise, as Posdaljian can be seen doing here with the acoustic releases that allow the instrument to float back to the surface after a year.

en: What are some of the challenges you face as a student?

NP: Dealing with imposter syndrome has been the biggest challenge. It’s very easy to doubt your abilities and feel inadequate in graduate school. It’s easy to lose sight of your accomplishments, and the long road to a PhD can become desolate. During these moments, I like to remind myself that this is part of bigger goals that I have for myself. And even though graduate school can be isolating, I rely on my support system to get me through times of low self esteem and remind me that I do belong here.

 

en: What are your plans post-Scripps?

NP: The intersection of academia and industry is very interesting to me! Academia is highly research and discovery focused. So, much of the research is done for the sake of learning. In industry, researchers usually feel a sense of immediate impact and their work tends to be more applied. And even though academia and industry are different, they have so much to learn from one another and there is so much potential for collaboration between the two.


You can find Posdaljian on Twitter and Instagram at @illuminatttttt.

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