Microscopic life forms in the ocean are crucial for reducing carbon dioxide levels in the atmosphere. A recent study reveals a hidden biological element that has the potential to transform our understanding of this process and enhance the accuracy of climate change forecasts.
Research led by Stanford University introduces an undiscovered factor that could reshape how we perceive the oceans’ role in combating climate change. The study, published on October 11 in Science, unveils new mucus “parachutes” created by tiny marine organisms that drastically slow their descent, thereby affecting the vital process of atmospheric CO2 elimination. This unexpected finding suggests that earlier evaluations of the oceans’ capacity to sequester carbon might have been overstated, while also providing pathways to refine climate modeling and guide policymakers in mitigating climate change.
“We haven’t been focusing on the right aspects,” stated Manu Prakash, the senior author of the study and an associate professor at Stanford in bioengineering and ocean studies. “Our findings highlight the significance of basic scientific observation and the necessity of investigating natural processes in their actual habitats, which is indispensable for tackling climate change.”
The biological pump
Marine snow, composed of decaying phytoplankton, bacteria, fecal particles, and other organic materials, captures approximately one-third of the carbon dioxide emitted by human activities and transports it to the ocean floor where it remains for thousands of years. While scientists have understood this process—termed the biological pump—for some time, the specific mechanisms that dictate how these fragile particles descend (given that the ocean averages a depth of 4 kilometers or 2.5 miles) remained unclear until now.
The researchers unraveled this mystery with an innovative device—a rotating microscope crafted in Prakash’s lab that redefines the approach. This apparatus follows the motion of organisms, simulating vertical travel across vast distances, while regulating factors like temperature, light, and pressure to replicate specific oceanic conditions.
During the last five years, Prakash and his lab team have utilized their specially designed microscopes on research expeditions across the globe—from the Arctic to Antarctica. On a recent trip to the Gulf of Maine, they collected samples of marine snow using traps submerged in the water, then promptly analyzed the sinking behavior of these particles with their rotating microscope. Since marine snow functions as a living ecosystem, completing these assessments at sea is crucial. This rotating microscope provided the team with an unprecedented opportunity to observe marine snow within its natural habitat with remarkable detail for the first time.
The findings astonished the scientists. They discovered that marine snow occasionally forms parachute-like mucus structures that nearly double the duration that the organisms remain suspended in the upper 100 meters of the ocean. This extended stay increases the chances of other microorganisms breaking down the organic carbon in the marine snow, converting it back into accessible organic carbon for other plankton, which delays the absorption of carbon dioxide from the atmosphere.
Beauty and complexity in the smallest details
The team considers their work a prime example of observation-based research, essential for understanding how even minute biological and physical processes operate within natural systems.
This research highlights a significant point: for the last two centuries, scientists have examined living organisms, including plankton, in a two-dimensional plane, confined under glass slides in a lab. Conversely, capturing high-resolution images via microscopy in open waters poses a considerable challenge. Chajwa and Prakash stress the necessity of conducting scientific observations as close to the natural settings as possible.
They argue that supporting research prioritizing observations in actual environments should be a primary focus for funding bodies in both public and private sectors.
Beyond its necessity for accurately quantifying marine carbon sequestration, the research also illuminates the inherent beauty found in everyday occurrences. Just like how sugar dissolves in coffee, the process of marine snow sinking into the ocean depths is governed by a complex range of factors that are often overlooked.
“We often take for granted specific phenomena, but even the simplest concepts can have significant implications,” Prakash noted. “Recognizing these finer details—such as the mucus tails of marine snow—opens up new avenues for understanding foundational principles of our universe.”
The researchers are now focused on refining their models, incorporating these datasets into vast Earth-scale models, and making available a comprehensive dataset from their six global expeditions thus far. This dataset is expected to be the largest collection of direct measurements of marine snow sedimentation. They also plan to investigate factors affecting mucus production, including environmental stressors and specific bacterial species.
While this discovery significantly alters current perspectives on oceanic carbon sequestration, Prakash and his team remain optimistic. On a recent expedition off Northern California’s coast, they identified mechanisms that could potentially accelerate carbon sequestration.
“With each observation of the plankton realm through our tools, I gain new insights,” Prakash said.
