Publication Spotlight – Dinoflagellate metabolism across the central Pacific Ocean
BY ALLY HUGHES
We interviewed first author, Dr. Natalie Cohen, about her work recently published in Nature Microbiology)
Dr. Natalie Cohen (Credit: Dr. Natalie Cohen)
What are dinoflagellates and why are they important to study?
Dinoflagellates are single-celled eukaryotes that are capable of photosynthesis, heterotrophy (eating), or both. They have a few several noteworthy characteristics: they can travel vertically in the water column using their flagella, they are capable of bioluminescence which can light up the ocean at night(!), and some coastal species produce toxins that can harm fish, birds and people. They are found throughout the world’s oceans and an important component of the ocean carbon cycle.
How did this project come to fruition?
Data from this project was collected in 2011 – this was my very first year of graduate school as a wee lad, and I had no idea this research cruise was happening in the equatorial Pacific! I didn’t join the project until my postdoctoral appointment, which began in 2017. My postdoctoral advisor, Mak Saito, was co-chief scientist on the Metzyme cruise, and orchestrated the collection of biomass and seawater samples. It’s such a huge data set consisting of transcripts, proteins, pigments, and geochemistry, and many individuals processed the raw data in the years before I officially joined the project.
Metzyme cruise, 2011 (Photo credit: Brian DiMento)
What are the main highlights from this paper?
My first examination of this data set showed a high relative abundance of dinoflagellates in the transcript and protein pools, which we were not expecting. I read about how diatoms commonly occur in the equatorial Pacific, especially when the micronutrient iron is introduced, but I hadn’t read much about the dinoflagellates. And, they were relatively abundant not only in surface waters, but also in the mesopelagic zone. We deduced that they must have a distinct and effective set of strategies that allow them to outcompete other phytoplankton in surface waters and other heterotrophs in the deep ocean, and therefore are important members of the microbial community across huge expanses of the Pacific.
Metzyme cruise, 2011 (Photo Credit: Brian DiMento)
Will you continue with this project? What is the next step?
At the very last station of this research cruise, samples were collected directly above a hydrothermal plume! We didn’t realize this until processing the seawater samples for dissolved trace metal concentrations back in the lab. I’ve been focusing on this hydrothermal metal plume and its potential influence on the deep sea microbial community.
In terms of the dinoflagellates, there is much to be understood about their physiology and ecological roles in the open ocean. It would be incredible to get some of these offshore dinoflagellates in culture, where we can explore their feeding habits, life cycles, and nutrient acquisition strategies in a controlled environment.
If this study was of interest to you, you’re in luck! Dr. Cohen is looking for students to join her research lab at UGA in Savannah, Georgia, USA:
I am absolutely looking for curious graduate and undergraduate students to join my lab group! We seek to understand how marine microeukaryotes respond to variations in their geochemical environment, and the implications for ecosystem function and ocean biogeochemistry. We combine techniques from molecular biology, environmental bioinformatics, and trace metal geochemistry. If interested, please see our website for more information and feel free to reach out! www.CohenLabUGA.com