Marine snow is a blend of decaying plankton, excrement, mucus, and other organic matter. Yet our understanding of this exceedingly important pathway in the ocean carbon cycle has some of the biggest knowledge gaps. Recent research by scientists Sasha J. Kramer and Colleen Durkin has illuminated the significance of marine snow in sequestering carbon from the Earth’s atmosphere. Their discoveries, published in The ISME Journal, show how vital microscopic processes are in regulating the global climate.
The study focused on understanding how certain phytoplankton groups, particularly diatoms and photosynthetic Hacrobia, can help predict the magnitude of carbon export into the deep ocean. This work was among many EXPORTS field campaigns in the North Atlantic and North Pacific. The ocean is Earth’s biggest carbon container, sequestering vast quantities of carbon from the troposphere. The mechanisms underlying this sequestration are perhaps the least understood mechanism of the global carbon cycle.
The Importance of Marine Snow
Marine snow forms when organic material sinks out of the surface of the ocean. This second process, mineralization, is the key to moving carbon to a stable, deeper layer of earth where it can be stored away from the atmosphere for millennia. Marine snow is an important component to ocean ecosystems and even climate regulation. We know how it interacts with various biotic components and their contributions to carbon export very thoroughly.
Kramer and Durkin’s research highlights that diatoms and Hacrobia are not just passive participants. They play an active role in determining how much carbon will eventually reach the ocean’s depths. The research team has made significant progress toward understanding these complex interactions. They looked at 18S rRNA gene sequences recovered from both phytoplankton collected directly in surface seawater and in marine snow aggregates.
“Marine snow—a mixture of dead plankton, waste, mucus, and other organic material slowly sinking from the ocean’s surface—is an important, but poorly understood, part of the ocean carbon cycle.” – Phys.org
Developing Predictive Models
Kramer and Durkin performed an exhaustive analysis. To address this knowledge gap, they created a novel predictive model that serves to bridge surface ocean phytoplankton communities to ecological mechanisms in the deep ocean. This new model is designed to improve initiatives to bridge satellite observations of surface ocean conditions with information from the deep sea.
Kramer stressed the importance of this model for performing research and predicting climate in the future.
“This research represents a major advance in quantifying the ocean carbon cycle. We’ve developed a predictive model for ocean carbon export that links surface ocean phytoplankton communities with the ecological mechanisms that occur in the deep ocean. This model will improve efforts to link satellite observations of the surface ocean to the deep sea, better predict the impacts of climate change, and evaluate the effectiveness of future ocean-based climate interventions.” – Sasha Kramer
These advancements hold promise for better understanding how climate change affects marine ecosystems and how intervention strategies can be optimized.
Integrating Microscopic Insights with Global Climate Drivers
The research team recognizes that in order to tackle climate change, we need new and creative ways to find a clearer view of our ocean ecosystems. Colleen Durkin emphasized the challenges of observing processes and mechanisms at very small scales while trying to combine that understanding with larger climate drivers.
“Responding to the climate crisis will require major leaps forward in our ability to monitor the ocean ecosystem. We must find new ways to observe the processes occurring on the microscopic scale and integrate that perspective with the climate drivers occurring on the global scale.” – Colleen Durkin
Durkin added that learning more about these tiny processes is key to understanding what effects they might have on the larger world.
“The ocean and its inhabitants export carbon on a massive scale, all driven by tiny phytoplankton. Microscopic processes translate to global impact.” – Colleen Durkin