Amid growing concerns over global warming, scientists are exploring an unconventional solution to combat atmospheric carbon dioxide (CO2) and mitigate climate change: tiny poop from microscopic marine life called zooplankton.
The study by researchers from Dartmouth College, recently published in Nature, reveals that marine microorganisms, aided by clay minerals, could enhance carbon sequestration by releasing carbon-filled feces in the water, offering a novel strategy for accelerating the ocean’s natural removal of CO2 from the atmosphere.
According to researchers, this novel approach could significantly bolster the biological carbon pump, a natural process that locks carbon away in the ocean’s depths.
“Normally, only a small fraction of the carbon captured at the surface makes it into the deep ocean for long-term storage,” study co-author and professor of earth sciences at Dartmouth, Dr. Mukul Sharma, said in a statement. “The novelty of our method is using clay to make the biological pump more efficient—the zooplankton generate clay-laden poops that sink faster,”
The biological carbon pump is a well-known mechanism by which phytoplankton and microscopic marine plants capture atmospheric CO2 through photosynthesis.
When these organisms die or are consumed, some of their carbon sinks into the deep ocean, where it can remain sequestered from the atmosphere for centuries. However, much of this carbon is lost before reaching the ocean floor due to microbial decomposition.
Dartmouth researchers, however, have found that clay minerals—key components of continental dust—could significantly enhance this process. By binding with organic matter in seawater, clay triggers the formation of “organoclay flocs,” dense particles that sink rapidly and resist degradation. This mechanism not only boosts carbon burial but also holds potential as a scalable solution for removing CO2 from the atmosphere.
To explore the interaction between clay and marine organisms, the research team conducted a microcosm experiment using water samples from the Gulf of Maine’s spring phytoplankton bloom. Clay was added to these samples in varying concentrations, and the results were striking.
Transparent Exopolymer Particles (TEPs), sticky organic substances that help form aggregates, increased tenfold in treated water. These aggregates, enriched by clay, sank rapidly to the bottom of the containers, simulating deep-sea sequestration.
Crucially, the flocs trapped carbon-rich phytoplankton and altered the microbial and planktonic communities. Diatoms, a type of phytoplankton with silica-rich shells, thrived in this clay-amended environment, while dinoflagellates—typically less effective at carbon sequestration—declined. The addition of clay shifted the ecosystem in a way that favored carbon export.
The study also examined the role of zooplankton, small animals that graze on phytoplankton and produce fecal pellets—a key component of the carbon pump.
When fed a mixture of clay and algae, copepod (a type of zooplankton) fecal pellets were denser and sank up to 3.6 times faster than those without clay. This enhancement in sinking speed reduces the likelihood of carbon being recycled back into the atmosphere, boosting long-term sequestration.
“This particulate material is what these little guys are designed to eat. Our experiments showed they cannot tell if it’s clay and phytoplankton or only phytoplankton—they just eat it,” Dr. Sharma explained. “And when they poop it out, they are hundreds of meters below the surface, and all that carbon is, too.”
Admittedly, using tiny poop to combat climate change is slightly amusing. However, the implications of this research could be profound. By leveraging natural processes in the ocean, this method could offer a sustainable and relatively low-cost way to combat climate change. Spraying clay minerals over targeted ocean regions, particularly during phytoplankton blooms, could amplify carbon capture on a large scale.
“Not only does the dust provide nutrients driving up productivity, but the clay minerals in the dust also provide surfaces that absorb organic molecules dissolved in seawater,” researchers wrote. “Certain bacteria, particularly heterotrophs, can detect and attach to solid surfaces including those of clay minerals initiating aggregation and organoclay floc formation.”
“Zooplankton feeding on organoclay flocs egest rapidly settling fecal pellets potentially releasing them below the euphotic zone during their daily vertical migration.”
While the results are promising, the method is not without challenges. Scaling up the deployment of clay and understanding its ecological impacts require further study. The method’s cost-effectiveness and potential to disrupt marine ecosystems also need to be evaluated.
However, the researchers are optimistic. Given the vast quantities of natural clay available and its compatibility with marine environments, this approach could complement other climate mitigation strategies, such as reforestation and carbon capture technologies.
“It is very important to find the right oceanographic setting to do this work. You cannot go around willy-nilly dumping clay everywhere,” Dr. Sharma said. “We need to understand the efficiency first at different depths so we can understand the best places to initiate this process before we put it to work. We are not there yet—we are at the beginning.”
Nevertheless, the urgency of addressing climate change cannot be overstated. Researchers highlight that mineral dust deposition on the ocean’s surface has long played a natural role in reducing atmospheric CO2. This newfound understanding of clay’s potential could revolutionize carbon sequestration strategies, bringing us closer to achieving critical global climate targets.
Ultimately, as unconventional as it may seem, the idea of tiny poop helping to save the planet is a reminder of nature’s ingenious solutions to global problems. While the science behind clay-laden fecal pellets may sound complex, the principle is simple: even the smallest creatures can make a significant impact.
If zooplankton can play a role in mitigating climate change one tiny poop at a time, perhaps it’s time we all took inspiration from their commitment to the cause—because when it comes to saving Earth, every little bit truly counts.
Tim McMillan is a retired law enforcement executive, investigative reporter and co-founder of The Debrief. His writing typically focuses on defense, national security, the Intelligence Community and topics related to psychology. You can follow Tim on Twitter: @LtTimMcMillan. Tim can be reached by email: tim@thedebrief.org or through encrypted email: LtTimMcMillan@protonmail.com