Brian Hunt / UBC
The researchers aim to increase oceanic carbon sequestration by introducing clay particles into the zooplankton’s diet, taking advantage of their natural eating habits.
Dartmouth researchers have introduced an innovative approach to mitigating climate change by leveraging natural feeding habits of zooplankton.
published in the journal Nature Scientific Reports, proposes the biological carbon pump booster from the ocean through the use of clay particles, which accelerate the sequestration of atmospheric carbon in the deep ocean.
The method begins with spraying clay powder onto the ocean surface at the end of the algal bloom. These blooms annually remove about 150 billion tons of carbon dioxide, converting it into organic carbon particles.
However, much of this captured carbon is typically released into the atmosphere as blooms decompose. The research team found that clay bonds with carbon particles, forming sticky flakes that zooplankton quickly consume. The animals then excrete these granules of carbon-laden clay to great depths, effectively transporting the carbon to the ocean floor for long-term storage.
According to Mukul Sharma, professor of Earth Sciences and lead author of the study, this approach significantly improves the efficiency of the biological pump. “You clay-laden poops generated by zooplankton sink more quickly, accelerating the carbon burial process”, explained Sharma at the American Geophysical Union annual conference.
The team conducted experiments using water samples from the Gulf of Maine during an algal bloom in 2023 and found that clay-coated organic carbon particles not only sank faster, but also reduced bacterial activity which normally releases carbon back into the atmosphere.
In treated seawater, sticky organic particles capable of sequestering carbon increased 10 times. Additionally, unconsumed carbon-clay flakes increased in size as they sank, further increasing carbon capture, explains .
The study highlighted the diurnal vertical migration of zooplankton – a daily movement from deep water to the surface – to illustrate the potential for efficient carbon transport. By feeding near the surface and returning to deeper waters, these microscopic creatures accelerate the transfer of carbon to the deep ocean.
Sharma plans try this method don’t worryo off the coast of Southern California, using clay dust from planes that dust off crops. Sensors at various depths will monitor zooplankton interactions with clay flakes and carbon to optimize the timing and location of large-scale application.
Despite the promising results, Sharma stressed caution. “It is crucial to identify the correct oceanographic configurations to ensure method efficiency and environmental safety.”
