‘Marine snow’ using tiny ‘parachutes’ has a big impact on ocean carbon storage

A recent discovery about "marine snow" is altering our theories on how Earth's oceans store carbon and help mitigate climate change.

Scientists have found that microscopic marine organisms produce mucus "parachutes" that slow down their descent to the ocean floor.

This finding could change our understanding of carbon dioxide removal from the atmosphere.

Manu Prakash , an associate professor of bioengineering and of oceans at Stanford University , led the study. His team's work suggests we've been missing a crucial piece of the puzzle.

Prakash and his colleagues have been exploring the mysteries of the ocean for years. Their research focuses on tiny particles and organisms that play a big role in our planet's health.

By observing these minute details, they hope to gain insights that could help combat climate change.

Understanding microscopic marine organisms

Tiny ocean organisms, like phytoplankton and zooplankton, play a crucial role in our oceans' health and the planet's climate.

These tiny creatures drift through the water, performing photosynthesis to produce oxygen and form the base of the marine food web.

Without them, larger marine animals wouldn't have the sustenance they need to survive. Phytoplankton alone contribute to about half of the world's oxygen supply, making them indispensable for life on Earth.

Beyond their role in producing oxygen, these microorganisms are vital in regulating carbon dioxide levels in the atmosphere.

As they consume carbon during photosynthesis, they help reduce greenhouse gases, mitigating the effects of climate change.

Mystery of marine snow

Marine snow is a mix of these microscopic dead organisms, including phytoplankton , bacteria, fecal pellets, and other organic particles. It absorbs about a third of human-made carbon dioxide from the atmosphere.

This material sinks to the ocean floor , where the carbon is locked away for thousands of years. Scientists call this process the biological pump.

Until now, the exact way these particles fall through the ocean's depths -- averaging about 2.5 miles -- wasn't fully understood. Prakash's team set out to change that.

Rotating microscope

The researchers developed a unique device called a rotating microscope.

This invention simulates vertical movement, allowing them to observe how organisms travel through the water. It adjusts temperature, light, and pressure to match specific ocean conditions.

Over five years, the team took this microscope on research vessels across all major oceans -- from the Arctic to Antarctica. They collected samples of marine snow and analyzed how it sinks in real-time.

Surprising role of mucus "parachutes"

What they found was unexpected. Sometimes, marine snow forms parachute-like mucus structures.

These mucus parachutes slow down the sinking process, doubling the time the particles spend in the upper 100 meters of the ocean.

"We haven't been looking the right way," Prakash said. This extended suspension means more microbes can break down the organic carbon in marine snow.

Instead of sinking and storing carbon away, the carbon gets recycled back into the ocean, reducing the amount removed from the atmosphere.

Marine snow and ocean carbon

Since marine snow is a living ecosystem, studying it at sea is crucial. The rotating microscope allowed the team to see these processes in detail, right where they happen.

Rahul Chajwa , a postdoctoral scholar in Prakash's lab and the study's lead author, was amazed by the findings.

“Theory tells you how a flow around a small particle looks like, but what we saw on the boat was dramatically different,” Chajwa explained. “We are at the beginning of understanding these complex dynamics.”

These mucus parachutes mean that previous estimates of the ocean's ability to sequester carbon might be too high.

If more carbon is recycled near the surface, less is stored deep in the ocean. This could have significant impacts on climate models and policies aimed at reducing atmospheric carbon dioxide .

Studying natural environments

“We cannot even ask the fundamental question of what life does without emulating the environment that it evolved with,” Prakash explained.

“In biology, stripping it away from its environment has stripped away any of our capacity to ask the right questions.”

For too long, scientists have studied organisms in artificial settings, like slides under microscopes. By taking their tools to the high seas, Prakash's team is changing that approach.

Refining ocean carbon models

The researchers are now working to improve their models and integrate their findings into larger climate models.

They plan to release an open dataset from their six global expeditions -- the largest of its kind on marine snow sedimentation.

They're also investigating what factors influence the production of these mucus parachutes. This could include environmental stressors or specific bacteria species.

Despite the challenges, Prakash remains optimistic. On a recent trip off the coast of Northern California, the team found processes that might speed up carbon sequestration.

"Every time I observe the world of plankton via our tools, I learn something new," he said. These discoveries could lead to new strategies for enhancing the ocean's ability to absorb carbon.

Marine snow, parachutes, and ocean carbon

Beyond the scientific implications, this study highlights the wonder of natural processes.

“We take for granted certain phenomena, but the simplest set of ideas can have profound effects. Observing these details -- like the mucus tails of marine snow -- opens new doors to understanding the fundamental principles of our world," Prakesh concluded.

By paying attention to the small details, we can uncover secrets that have a big impact on our world. This research is a reminder of the importance of curiosity and the pursuit of knowledge.

The full study was published in the journal Science .

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