Plastic that finds its way into the ocean pretty much stays there forever, said UC Santa Barbara marine microbiologist Alyson Santoro. She's a lead scientist on a project to develop biodegradable plastic for the ocean.
“We want to develop a material that the naturally occurring microbes in the ocean can break down into harmless carbon dioxide and water,” she said.
Some biodegradable materials do exist for use on land, but Santoro said the ocean environment presents different challenges.
“Those materials have been thoroughly tested to break down in terrestrial composting facilities which tend to be anoxic and relatively high temperature, and the ocean is exactly the opposite of that,” Santoro said.
Her team received a National Science Foundation (NSF) Convergence Accelerator grant in 2021 to pursue the idea of biodegradable ocean plastics for the blue economy. The blue economy includes industries like shipping, fishing and tourism that operate in and around the ocean.
Santoro said the team is focused on developing biodegradable marine sensors that are used by oceanographers and others to gather all types of data – from weather to national defense. She said the sensors are abandoned at sea when no longer needed and, currently, they don’t biodegrade.
“We know that the initial target market is a pretty small piece of the overall marine plastics problem but we’re hoping that by focusing on that industry first, we can increase the adoption of these biodegradable plastics,” she said.
Santoro’s project, called Nereid Biomaterials, recently received funding for Phase 2. She said Phase 1 was about design and feasibility, and now it’s time to make a product. Unlike other research grants, Santoro said this one has the added element of seeing the project all the way through to production.
“The goal is to really have a stand-alone entity by the end of this two years,” she said.
The project team includes other scientists, engineers, and industry partners – that’s the convergence part of the grant where multiple fields come together to rapidly solve problems.
She said the team’s prototypes are 3D printed and made with a natural polymer filament from partner Mango Materials. The small objects are placed in underwater locations on both the East and West Coasts – including an area not far from Santoro’s office at UCSB.
“I do have a mooring that is in the middle of the Santa Barbara Channel. It’s operated in collaboration with the Channel Islands National Marine Sanctuary. They’re one of our collaborators on this project,” Santoro said.
There’s still a lot to learn but, so far, she said the results are encouraging – it seems ocean bacteria can break down the prototype samples.
“This material actually degrades quickly enough that within six months we can have a measurable mass loss from these objects,” she said.
In addition to measuring changes in weight, they also use high resolution electron microscopes to see how the objects biodegrade.
“When we bring them back, we can actually see bacteria that are tunneling into this material,” Santoro said.
The NSF grant includes funds for paid internships. UCSB undergraduate students can participate in the science, engineering, and business aspects of the project.
Santoro said developing a truly biodegradable material for marine sensors is just the beginning. She expects that the findings will be applicable to many other consumer products going forward.
The project website is nereidbio.org
