La Jolla biologist finds disturbing marker of human life

Scripps Institution of Oceanography biologist Jenni Brandon unwraps the sediment sample that helped her make a grim discovery about plastic accumulation in the ocean.

How do you protect a core sample of seafloor that’s just helped you make a revolutionary scientific discovery about plastic contamination in the oceans?

Jenni Brandon, a Scripps Institution of Oceanography biologist who specializes in plastic contamination, recently toured the Light around Scripps’ Core Collection, a room where 15,000 tubes of ocean sediment — one of the largest U.S. collections — are kept at 38 degrees and sealed in plastic wrap.

“Yes, I suppose it is ironic,” Brandon said as she unwrapped the core that helped her make headlines earlier this month. (To counteract any contamination added by the wrap, a spectral signature of every core is recorded before wrapping, and any hits for that exact plastic are removed from the results.)

The core was taken in 2010 by Scripps paleobiologist Bill Jones, off Santa Barbara, to study fish scales deposited since 1834. Brandon wondered what she would see if she re-analyzed it.

“I asked Bill, ‘Do you think I’ll see plastic?’ ” Brandon recalled. “And he said, ‘Even looking for fish, I couldn’t avoid the plastic. You’re going to find plastic.’”

Brandon’s discovery — that plastic deposits double about every 15 years — were published in the journal Science Advances.

“I wasn’t surprised that it was increasing over time,” Brandon said. “I was surprised just how fast it was increasing. It was this exponential, not-stopping line.”

It is believed that this line represents the boom in plastics production worldwide after 1945. Before then, almost none was present in the sample. Brandon said the discovery supports the idea of using plastic accumulation as a defining signifier of the Anthropocene, a proposed new geological epoch marked by humanity’s effect on Earth.

“I hope that this paper shows that we’re leaving plastic behind in our fossil record,” Brandon said. “What our generation could be remembered for is this much plastic, and that this is hopefully a call to action.”

A native of Palo Alto who now lives in Encinitas, Brandon developed her plastic obsession while studying at the Duke University Marine Lab. While she earned her Ph.D. in biological oceanography from Mark Ohman’s lab at Scripps, he encouraged her to dive further into plastic because, she said, “he studies plankton, and a lot of this microplastic is the same size as plankton, and he really wanted to know how it was interacting with it.”

When Brandon started this project — with Ohman on her research team — she said that “no one was talking about plastic.”

“I’d say I study plastic in the ocean and they’d be like, ‘What?’” she said.

“And now, any room I walk into, people are like, ‘Oh yeah, we studied the garbage patch. There’s plastic in the ocean. I know about that.’ ”

Now — thanks to discoveries made largely at Scripps — people are talking about ocean plastic in law, medicine and in every realm of engineering.

The form in which Brandon discovered most of the plastic contamination was also a surprise. Most was tinier than a speck of lint. Brandon speculates that much of it came from washing-machine wastewater over the decades.

“We already knew there were a lot of microfibers, but the fact that I found so many at the bottom, that really shows — as we’re studying how coral reefs and mussel beds how are affected — that we should really look at how microfibers specifically affect those animals,” Brandon said, adding that that ingesting plastic is known to cause physical damage to marine organisms that reverberate throughout the marine food web, but that this damage has not been studied enough.

Brandon poses amidst the more than 15,000 tubes of ocean sediment stored in a single refrigerated room at Scripps Institution of Oceanography.

Ironically, the reason plastic is such a great protector of the core Brandon employed is the same reason it doesn’t break down in the environment. It is almost completely inert.

“We’re in a plastic environment and labs are full of plastic,” Brandon said. “To build a plastic-free clean room is a daunting task.”

Though she can’t avoid it in her professional life yet, Brandon said she at least tries always to avoid it at the grocery store.

“I have reusable plastic produce bags and I’m really thoughtful about what I purchase,” she said. “I don’t buy things in individual snack packs, where it’s plastic within plastic within plastic, and I buy things in bulk.

“But every once in a while, you’ll see me make a mistake,” she admitted. “You can’t kill yourself over those tiny decisions.”