01-Dec-2022 - Pacific Northwest National Laboratory

Fertilizing the ocean to store carbon dioxide

Iron-based fertilizer, engineered into nanoparticles, could help store excess carbon dioxide in the ocean

The urgent need to remove excess carbon dioxide from Earth’s environment could include enlisting some of our planet’s smallest inhabitants, according to an international research team led by Michael Hochella of the Department of Energy’s Pacific Northwest National Laboratory.

Hochella and his colleagues examined the scientific evidence for seeding the oceans with iron-rich engineered fertilizer particles near ocean plankton. The goal would be to feed phytoplankton, microscopic plants that are a key part of the ocean ecosystem, to encourage growth and carbon dioxide (CO2) uptake. The analysis article appears in the journal Nature Nanotechnology.

“The idea is to augment existing processes,” said Hochella, a Laboratory fellow at Pacific Northwest National Laboratory. “Humans have fertilized the land to grow crops for centuries. We can learn to fertilize the oceans responsibly.”

In nature, nutrients from the land reach oceans through rivers and blowing dust to fertilize plankton. The research team proposes moving this natural process one step further to help remove excess CO2 through the ocean. They studied evidence that suggests adding specific combinations of carefully engineered materials could effectively fertilize the oceans, encouraging phytoplankton to act as a carbon sink. The organisms would take up carbon in large quantities. Then, as they die, they would sink deep into the ocean, taking the excess carbon with them. Scientists say this proposed fertilization would simply speed up a natural process that already safely sequesters carbon in a form that could remove it from the atmosphere for thousands of years.

“At this point, time is of the essence,” said Hochella. “To combat rising temperatures, we must decrease CO2 levels on a global scale. Examining all our options, including using the oceans as a CO2 sink, gives us the best chance of cooling the planet.”

Pulling insights from the literature

In their analysis, the researchers argue that engineered nanoparticles offer several attractive attributes. They could be highly controlled and specifically tuned for different ocean environments. Surface coatings could help the particles attach to plankton. Some particles also have light-absorbing properties, allowing plankton to consume and use more CO2. The general approach could also be tuned to meet the needs of specific ocean environments. For example, one region might benefit most from iron-based particles, while silicon-based particles may be most effective elsewhere, they say.

The researchers’ analysis of 123 published studies showed that numerous non-toxic metal-oxygen materials could safely enhance plankton growth. The stability, Earth abundance, and ease of creation of these materials make them viable options as plankton fertilizers, they argue.

The team also analyzed the cost of creating and distributing different particles. While the process would be substantially more expensive than adding non-engineered materials, it would also be significantly more effective.

Facts, background information, dossiers
More about Pacific Northwest National Laboratory
  • News

    Scientists unveil least costly carbon capture system to date

    The need for technology that can capture, remove and repurpose carbon dioxide grows stronger with every CO2 molecule that reaches Earth’s atmosphere. To meet that need, scientists at the Department of Energy’s Pacific Northwest National Laboratory have cleared a new milestone in their effor ... more

    Simple process extracts valuable magnesium salt from seawater

    Since ancient times, humans have extracted salts, like table salt, from the ocean. While table salt is the easiest to obtain, seawater is a rich source of different minerals, and researchers are exploring which ones they can pull from the ocean. One such mineral, magnesium, is abundant in t ... more

    Plastic upcycling: From waste to fuel for less

    A plastics recycling innovation that does more with less, presented at the American Chemical Society fall meeting in Chicago, simultaneously increases conversion to useful products while using less of the precious metal ruthenium. “The key discovery we report is the very low metal load,” sa ... more

  • Research Institutes

    Pacific Northwest National Laboratory

    The Pacific Northwest National Laboratory is dedicated to addressing the most intractable problems in energy, the environment and national security. Located in Richland, Washington, PNNL is one among ten U.S. Department of Energy (DOE) national laboratories managed by DOE's Office of Science. more

More about U.S. Department of Energy
  • News

    Scientists unveil least costly carbon capture system to date

    The need for technology that can capture, remove and repurpose carbon dioxide grows stronger with every CO2 molecule that reaches Earth’s atmosphere. To meet that need, scientists at the Department of Energy’s Pacific Northwest National Laboratory have cleared a new milestone in their effor ... more

    AI discovers new nanostructures

    Scientists at the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory have successfully demonstrated that autonomous methods can discover new materials. The artificial intelligence (AI)-driven technique led to the discovery of three new nanostructures, including a first-of-its- ... more

    A cool new method of refrigeration

    Adding salt to a road before a winter storm changes when ice will form. Researchers at the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) have applied this basic concept to develop a new method of heating and cooling. The technique, which they have named “ionoca ... more