A study by the Scripps Institution of Oceanography at UC San Diego has found a 100-fold upsurge in human-produced plastic garbage in the Great Pacific Garbage Patch within the Pacific Ocean. Researchers found that the plastic debris is disrupting habitats in the ecosystem — but not in the ways you might imagine.
In 2009, a team of graduate students led the Scripps Environmental Accumulation of Plastic Expedition (SEAPLEX) to the North Pacific Ocean Subtropical Gyre aboard the Scripps research vessel New Horizon. The researchers, who focused their studies on an area 1,000 miles west of California, documented an immense amount of human-generated trash, mostly tiny broken down bits of plastic the size of a human fingernail floating across thousands of miles of open sea.
The new study published by a graduate student researcher in the latest issue of the journal Biology Letters reveals that plastic debris in the area popularly known as the “Great Pacific Garbage Patch” has grown by 100 times over in the past 40 years, thereby altering the natural habitat of animals such as the marine insect Halobates sericeus.
“When you go out into the North Pacific, what you find can be highly variable. So, to find such a clear pattern and such a large increase was very surprising,” said graduate student and lead author of the study Miriam Goldstein.
These insects — known also as ”sea skaters” or “water striders” – inhabit water surfaces and lay their eggs on flotsam such as seashells, seabird feathers, tar lumps and pumice. Now, sea skaters have are using plastic garbage as new surfaces for their eggs, which is strongly increasing the insects’ egg densities in the gyre.
This increase, documented for the first time in a marine invertebrate in the open ocean, may affect animals across the marine food web, such as crabs that prey on sea skaters and their eggs.
“This paper shows a dramatic increase in plastic over a relatively short time period and the effect it’s having on a common North Pacific Gyre invertebrate,” said Goldstein, chief scientist of SEAPLEX, a UC Ship Funds-supported voyage. “We’re seeing changes in this marine insect that can be directly attributed to the plastic.”
The amount of plastic debris will influence the survival of species specifically adapted to life on or around objects floating in the water.
The new study follows a 2011 report by Scripps researchers showing that 9% of the fish collected during SEAPLEX had consumed plastic waste. That study estimated that such fish in the North Pacific Ocean ingest plastic at a rate of roughly 12,000-24,000 tons a year.
The new study compared changes in small plastic abundance between 1972-1987 and 1999-2010 through historical samples gathered from various sources. In April, researchers with the Instituto Oceanográfico in Brazil published a report that eggs of Halobates micans, another species of sea skater, appeared on many plastic bits floating in the South Atlantic off the Brazilian coast.
“Plastic only became widespread in late ’40s and early ’50s, but now everyone uses it and over a 40-year range we’ve seen a dramatic increase in ocean plastic,” said Goldstein. “Historically we have not been very good at stopping plastic from getting into the ocean so hopefully in the future we can do better.”