Voyager: As scientists study the effects of plastic-related toxins that marine organisms are ingesting, are they finding the chemical or physical effect to be more dangerous?

The physical effects of plastic entanglement and ingestion on large vertebrates like birds and whales are well known. For example, The Marine Mammal Center in Sausalito, Calif., recently found and dissected a sperm whale with 450 pounds of debris including fishing net and plastic bags in its stomach. However, Scripps SEAPLEX scientists are working on much smaller organisms. The biggest specimens, such as lanternfish, are just a couple of inches long.

Most of the plastic found in the North Pacific Gyre was equally small, little pieces less than a quarter-inch across. Since these pieces were so tiny, the researchers have not found evidence of physical effects such as entanglement or choking, though that doesn’t mean this never occurs. Fish researchers Pete Davison and Rebecca Asch of the SEAPLEX cruise found that some fish had eaten small pieces of plastic, but their intestines did not appear to be blocked. During the cruise Seabird researcher Andrew Titmus also observed an albatross pecking at lost fishing gear (sometimes called a “ghost net”), which may be one way that albatrosses and other seabirds are ingesting plastic. As for the chemical effects, the lab work is still ongoing and scientists don't have results yet.

Researchers are also investigating other ways that plastic can harm the open ocean ecosystem. For example, plastic may be changing the way fish move across the ocean. During the SEAPLEX cruise, scientists found tropical reef fish living underneath a ghost net in the middle of the ocean – and we definitely didn’t expect to see them there!

To learn more about the Pacific Ocean Garbage Patch read our story, “Inside the Plastic Vortex.”

-- Miriam Goldstein, graduate student researcher, Biological Oceanography