The ocean plays a large role in cycling carbon dioxide in the atmosphere. Determining how much carbon is locked away in the ocean is critical to understanding Earth’s changing climate. However, measuring and monitoring oceanographic processes on a massive scale poses a challenge to scientists. MBARI researchers and collaborators from Florida State University have developed a new method for analyzing satellite data to better predict the export of carbon. The team recently published their findings in the scientific journal Geophysical Research Letters. 

“We urgently need tools to monitor the ocean-carbon connection on a global scale. By leveraging diverse sets of data, we’ve identified a new path forward to improve carbon export estimates from space,” said Monique Messié, a senior research specialist who leads MBARI’s Data Integration and Interdisciplinary Oceanography Team and was lead author on the recent study. 

The ocean and its inhabitants are critical parts of Earth’s carbon cycle. Carbon dioxide dissolves into the ocean, and marine life converts it into organic material that later sinks into the deep sea. Together, these processes can lock away, or sequester, carbon from the atmosphere in the ocean’s depths, a process known as carbon export.

Direct measurements of carbon export are scarce, so scientists have to rely on models and satellite data to understand large-scale patterns in the ocean-carbon connection. Tiny plant-like phytoplankton in the ocean’s surface waters convert carbon dioxide into organic carbon via photosynthesis. Scientists can use satellite ocean color data to estimate phytoplankton productivity. However, existing satellite-based models often do not capture what happens below the ocean’s surface. 

Coastal upwelling in the California Current—a cool, nutrient-rich current running from British Columbia to Baja California—creates a boom of productivity. Ocean currents can carry phytoplankton hundreds of kilometers offshore. Marine life consumes phytoplankton, transporting carbon through the food web as food and waste. Dead phytoplankton and carbon-rich waste ultimately sink to the depths below, part of a biological pump that can lock carbon away in the deep sea for thousands of years.

MBARI’s Data Integration and Interdisciplinary Oceanography Team works to understand ocean processes by leveraging diverse datasets from various disciplines, from physics to ecosystems. 

The team is particularly interested in addressing which processes drive patterns of biological communities throughout the water column over time. These relationships are especially challenging to decipher because they are not always direct. For example, because plankton are displaced by currents, what we observe in one location may be the result of past conditions tens of kilometers away. The Data Integration and Interdisciplinary Oceanography Team develops models to untangle these effects and uncover which processes drive biological communities, describe how they occur, and quantify their impact.

MBARI has deployed a suite of advanced technologies at Station M, a research site offshore of Central California, to monitor the abyssal seafloor. The trove of data from this long-term observatory has helped researchers understand how carbon is cycled from the surface to the deep sea. 

MBARI researchers and collaborators had previously observed pulses of carbon to the deep seafloor that could not be explained by existing satellite-based algorithms of carbon export. Those algorithms model ocean physics and biogeochemistry, but do not consider the lag in both time and space between phytoplankton productivity at the surface and carbon export to the deep sea. Messié and a team of MBARI researchers and collaborators sought to identify a new avenue to improve estimates of carbon export. The team developed a Lagrangian growth-advection satellite-derived model that maps plankton succession and export onto surface oceanic circulation following coastal upwelling. The model was initially designed to track biological hotspots where marine life congregates.

Instead of relying on ocean color data to estimate carbon export, this new approach incorporates the offsets between production and export, the role of zooplankton, and advection of plankton blooms by ocean currents. This method performed as well as models that rely on ocean color or long-term monitoring of carbon raining down on the abyssal seafloor.

The team’s success demonstrates that export can be well represented from space without ocean color, using a plankton model and satellite-derived tracks of oceanic currents. These results provide new insights into what controls carbon export, how to represent it from space, and its spatiotemporal patterns in a productive oceanic region.

MBARI’s Data Integration and Interdisciplinary Oceanography Team will leverage this new model to better understand how deep-sea carbon fluxes are connected to surface processes. 

Next year, incoming MBARI Postdoctoral Fellow Théo Picard will work with Messié to explore what mechanisms drive the unexplained intense pulses observed in MBARI’s long-term monitoring at Station M. In addition to refining the Lagrangian growth-advection model of surface carbon export, Picard will use machine learning to build upon previous analyses to estimate surface area catchment at Station M and work with MBARI’s Carbon Flux Ecology Team to investigate the role of biological community composition.

“A complex web of physical and biological factors influence the oceanic carbon cycle. Using satellite data about winds and currents shows promise for estimating ocean carbon export, offering a complementary perspective to models that use ocean color visible from space. We hope the marine research community can build upon our work to better represent complex oceanographic processes from satellite data,” said Messié.

MBARI makes our research, technology, and data available to the wider marine science and technology community. Code and data for the Lagrangian growth-advection satellite-derived model are available via GitHub and Zenodo.

This research was funded by the David and Lucile Packard Foundation, with additional support from the U.S. National Science Foundation Grant OCE-2224726 to the California Current Ecosystem Long-Term Ecological Research (CCE-LTER) Program.

Research Publication:

Messié, M., C.L. Huffard, M.R. Stukel, and H.A. Ruhl. 2025. Spatial and temporal interplay between oceanic circulation and biological production in shaping carbon export off the California coast. Geophysical Research Letters, 52(7): e2024GL113707. https://doi.org/10.1029/2024GL113707

Story by Senior Science Communication and Media Relations Specialist Raúl Nava

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