Follow Dr. Nam on X or learn more about the research Dr. Nam and his team conduct here. A link to the specific paper our earlier news report and this interview pertains to can be found here.
In a groundbreaking study, Dr. Onyou Nam and his team from the Department of Biology at the University of York have uncovered crucial insights into diatom proteins and their role in enhancing the CO₂ reduction potential of oceans. This research highlights the remarkable efficiency of diatoms as natural carbon fixers and opens new pathways for sustainable climate change mitigation strategies.
As part of our detailed exploration of this topic, we spoke with Dr. Nam to delve deeper into the scientific breakthroughs, challenges, and future implications of his research. The following interview remains unedited to preserve the authenticity of Dr. Nam’s responses and provide readers with an in-depth understanding of the pioneering work conducted by his team.
Acknowledgement From Dr. Onyou Nam: I would like to thank the members of the Mackinder Group, especially those involved in this project, researchers from the Biology department in York, Jamie Blaza and Adam Dowle, collaborators from Basel, Ben Engel and Manon Demulder, and the funding agencies (in particular UK Research and Innovation). Without this awesome team, such research would have been impossible.
What led your team to focus on diatom proteins as a key to unlocking the CO₂ reduction potential in oceans, and what was the initial breakthrough in your research?
Our focus on diatoms, one of the major carbon fixers in the ocean, was driven by their pivotal role in global carbon fixation. They run a CO2-concentrating mechanism (CCM) via the subcellular organelle known as the pyrenoid, where the carbon-fixing enzyme Rubisco is densely packed in the matrix. The initial breakthrough was the identification of ten previously unknown proteins in the diatom pyrenoid. The discovery led us to move forward in understanding how diatoms achieve efficient carbon fixation under a dynamic marine environment.
Can you explain the role of diatom proteins in carbon sequestration and how this process differs from other biological or chemical methods?
The proteins in the pyrenoid facilitate the CCM to ensure efficient carbon fixation by Rubisco. To grasp pyrenoid-based CCM, we need to understand its key structural features. First is the Rubisco matrix, which has a highly condensed Rubisco. Next, an inorganic carbon delivery system is required to fuel Rubisco with its substrate CO2. Finally, a CO2 diffusion barrier is necessary to prevent CO2 leaking out from the pyrenoid. Compared to other biological systems, the diatom pyrenoid lacks the starch sheath found in eukaryotic green algae, relying instead on a protein-based barrier, which closely resembles the protein shells of prokaryotic carboxysomes. Unlike chemical CO₂ capture methods, which are often energy-intensive processes for chemical conversion, the diatom’s biophysical CCM operates passively within its natural environment, making it highly efficient and sustainable.
How do your findings contribute to our understanding of the natural carbon cycle and its potential enhancement through technological or ecological applications?
Our research offers critical insights into the structure and function of diatom pyrenoids, which are major drivers of the oceanic carbon cycle. By elucidating the role of the proteinaceous Shells in CCM, we provide molecular targets for bioengineering efforts to enhance pyrenoid-like structures in other organisms. These findings can pave the way for innovations in artificial carbon sinks and improvement of crop photosynthesis, leveraging diatom-inspired mechanisms to boost global carbon sequestration.
What are the practical implications of your research for large-scale CO₂ reduction efforts, and how might this translate into real-world environmental benefits?
The discovery of the structural role of Shell proteins highlights opportunities to harness diatoms for large-scale CO₂ reduction. Potential applications include bioengineering synthetic systems that mimic the pyrenoid’s CO₂-concentrating capabilities. Such innovations could reduce atmospheric CO₂ concentrations, mitigate ocean acidification, and support marine ecosystems, representing a multifaceted approach to climate change mitigation.
What challenges did you encounter when studying the interactions between diatom proteins and CO₂ in marine environments, and how did you overcome them?
At the start of the project, we faced a fundamental challenge as the molecular components of the diatom pyrenoid were largely unknown. Unlike well-studied pyrenoids in other microalgae, such as Chlamydomonas reinhardtii, diatom pyrenoids had no clearly identified structural or functional proteins beyond Rubisco. This lack of foundational knowledge made targeting specific pathways or mechanisms difficult.
To address this, we drew inspiration from studies on pyrenoid proteins in other microalgal species, analyzing their structural and functional characteristics to identify potential analogues in diatoms. We also used a protein identification method, leveraging fluorescence tagging and affinity purification-mass spectrometry to discover and validate novel candidate proteins systematically. This approach allowed us to identify previously uncharacterized Shell proteins that encapsulate the pyrenoid, which is critical to its architecture and CO₂-concentrating function. By combining insights from other systems with innovative molecular techniques, we built a spatial interaction network for the diatom pyrenoid, overcoming the initial lack of data. This methodology helped us overcome early obstacles and revealed unique diatom CCM features that could advance our understanding of marine carbon fixation.
Are there specific regions or conditions in the ocean where your discoveries could be most effectively applied, and how might this affect global carbon management strategies?
Diatoms are found globally, including regions like the Southern Ocean and coastal areas, and are well-suited for carbon management strategies due to their adaptability and efficient CO₂ fixation. Coastal regions, often overlooked, offer accessible sites to enhance diatom blooms, potentially increasing local carbon drawdown and mitigating ocean acidification. Current global strategies lack sufficient integration of biological systems for sustainable carbon sequestration, so a gap diatom-based approach could fill it. By leveraging diatoms’ CCM, natural carbon sinks could be amplified. However, the practical application requires further validation, including nutrient management, scalability, and ecological impacts. Pilot studies in diverse marine regions are essential to assess feasibility. If successful, diatom-based solutions could complement technological efforts, providing a scalable, sustainable method for global carbon management.
What are the next steps for your research, and how do you envision diatom protein studies influencing future policies or innovations in climate change mitigation?
The next steps in our research include further studying the newly discovered pyrenoid components, focusing on how they interact systematically to understand the diatom pyrenoid’s assembly, structure, and function. We will explore how these proteins contribute to enhancing efficient CO₂ fixation.
We envision that diatom pyrenoid studies will inform climate policies. Understanding and optimizing the diatom CCM may offer a natural, sustainable solution to alleviate future climate challenges. This would encourage the integration of biological systems into carbon management strategies and drive innovations in sustainable climate change mitigation technologies.
