Island University Ph.D. Student Studies Plastic Eating Microbes

CORPUS CHRISTI, Texas – According to a study published in "Science," more than 5 billion tons of plastic pollute the ocean. While many studies concern the effects of plastic pollution, there’s still much to learn about how microorganisms interact with plastic. Lee Pinnell, a doctoral student studying microbial ecology at Texas A&M University-Corpus Christi, recently collected his final samples of plastic eating microorganisms, which he placed in the Laguna Madre as part of his dissertation.

“Plastic debris affects more than our shoreline and aquatic animals aren’t the only ones that consume plastic,” said Pinnell. “When sea life eat discarded plastics, that plastic could eventually work its way back up to the food chain and into humans.”

To help prevent plastics cluttering our shoreline and our diet, Pinnell recommends recycling and limiting single-use plastics like grocery bags.

“If petroleum-based plastic goes into the environment, it’s going to be there for a long time,” said Pinnell. “This study reinforces that if we don’t properly dispose of our plastic waste, it’s a big issue, especially in areas like the Texas coast.”

To study how microorganisms respond differently to biodegradable plastics and petroleum-based plastics, Pinnell placed containers of different small plastic pellets in the Laguna Madre. He included ceramic pellets as a control. Pinnell discovered that microorganisms respond differently to biodegradable plastics and petroleum-based plastics. Pinnell chose the Laguna Madre as the location for his study for several reasons: it’s local, he’s able to access the University’s field station and the amount of plastic debris are often much higher in coastal regions. The Laguna Madre is a water body that stretches along the western coast of the Gulf of Mexico, between the Nueces River and the Rio Grande.

“We found that the microbes are living on the ceramic pellets, the petroleum-based plastic and the bioplastic,” explained Pinnell. “But the microbes are only interacting with and biodegrading the bioplastics. We also found that the microbial communities on the ceramic pellets and the petroleum-based plastics are similar to each other while the microbial community on the bioplastic was unique.”

Pinnell is interested in isolating the microorganisms that break down the biodegradable plastic once his data analysis is complete. While it can be considered “good” that the biodegradable plastic can be broken down, it is still unknown how the microorganisms are fully affected.

Pinnell conducts his research through Dr. Jeff Turner’s Laboratory for Microbial and Environmental Genomics at A&M-Corpus Christi. Through studying how ecosystem change affects microbial populations, Pinnell will have a fuller understanding of pollution’s impact. His research has been funded by Texas Sea Grant, the Texas Coastal Management Program and Texas Research Development Fund.