A New Study Challenges the Role of Diatoms in Ocean Carbon Storage
A recent study led by the UK National Oceanography Centre (NOC) has raised doubts about the conventional wisdom regarding the contribution of diatoms, a type of plankton, in driving ocean carbon storage. Diatoms, known for their silica-based exoskeletons, were believed to play a crucial role in transporting carbon to the deep ocean, but the findings of this study suggest otherwise.
The research, based on data from expeditions to the Southern Ocean’s twilight zone, revealed that diatom skeletons tend to remain near the sea surface while carbon is transported to the deep ocean through other mechanisms. This unexpected discovery challenges our understanding of the biological carbon pump, a set of processes in which plankton help sequester carbon in the ocean.
Dr. Sari Giering, the lead researcher at NOC, emphasized the significance of this finding, stating, “The surprising discovery that diatoms’ silica skeletons stay near the surface while carbon makes it down to the deep ocean forces us to rethink the ecological processes in what we call the biological carbon pump.”
Implications for Ocean Warming and Carbon Storage
One of the concerns addressed in the study was the potential impact of ocean warming on diatom productivity and, consequently, on the strength of the biological carbon pump in the Southern Ocean. While ocean warming could affect nutrient availability and diatom populations, the study suggests that these changes may not significantly alter carbon storage in the region.
Lead author Jack Williams, a post-graduate researcher at the University of Southampton, explained, “Our results suggest that ocean warming may not have as drastic an impact on Southern Ocean carbon storage as previously thought. However, there are still unknown processes at play in the twilight zone that require further investigation.”
Research Methodology and Funding
The study was conducted as part of two NOC-led initiatives, COMICS and CUSTARD, funded by the UK’s Natural Environment Research Council (NERC) and the European Research Council. Over two expeditions spanning more than five weeks each, researchers studied the twilight zone in the Atlantic and Pacific sectors of the Southern Ocean using innovative techniques such as ship-based measurements and autonomous underwater technologies.
By exploring different oceanic conditions and employing advanced research methods, the team was able to gain valuable insights into the processes governing carbon uptake in the Southern Ocean. This knowledge is essential for predicting how the oceans will store carbon in the future.
Overall, the study highlights the complexity of oceanic carbon storage and underscores the need for continued research to better understand the role of diatoms and other marine organisms in this critical process.