Cleaning up ocean ‘garbage patches’ could destroy delicate ecosystems | Science

Removing trash from the ocean may not be as harmless as it seems. That’s the conclusion of new research, which finds that marine dumps known as “garbage patches” are home to countless delicate creatures that could perish when people scoop debris from the sea.

The oceans are home to five major garbage patches. They form far from land where strong currents swirl together, ferrying trash of all sizes. Some of it has been eroded by the churn into tiny debris known as microplastics.

The largest of these marine debris fields is known as the Great Pacific Garbage Patch. Spanning 1.6 million square kilometers midway between Hawaii and the coast of California, it was first observed in 1997 by Charles Moore, an oceanographer and founder of Algalita Marine Research and Education. The patch escaped notice for so long because most of its contents aren’t easily spotted from afar.

To see whether the Great Pacific Garbage Patch was harboring a cluster of floating creatures in addition to floating waste, a crew sailed through the patch for 80 days, collecting samples from Hawaii to the coast of San Francisco. “These mysterious regions are largely unexplored,” says Rebecca Helm, a biologist at Georgetown University.

The samples revealed high concentrations of three species that hover at the ocean’s surface. They included blue button jellies (jellyfishlike organisms that grow to about 3 centimeters wide), by-the-wind sailors (up to 10-centimeter-long creatures with translucent natural sails that help them drift in the wind), and violet snails (which float using bubbles and live in golf ball–size shells). Blue button jellies and by-the-wind sailors feed on plankton and serve as food for violet snails.

The scientists matched the locations of these creatures with high concentrations of plastic debris. That hints that ocean currents shepherd all of these floating objects—both life and trash—in the same way, the team reports this month in PLOS Biology.

Helm says the presence of these creatures implies a complex ecosystem in which they serve as food for predators like sea turtles and seabirds. “These animals don’t exist in isolation,” she says. “The food web they’re a part of affects the whole ocean.”

That could complicate efforts to clean up these patches. Some environmental organizations aim to remove the waste by skimming the surface with nets. But just as similar fishing methods lead to bycatch–creatures like dolphins caught accidentally while targeting commercial species such as shrimp–such cleanup efforts would likely scoop up surface-dwellers along with the debris, Helm says. Indeed, a modeling study published last month in Aquatic Biology found such efforts could potentially threaten the survival of species that have flourished for millions of years.

“I call it King Neptune’s nursery,” says Moore, who was not involved in either study. “Many creatures found there are delicate because they’re used to calm conditions.” Human activity could upset the balance, though Moore suggests the influx of plastic waste is already doing so. Based on his personal observations, as the volume of plastic in the Great Pacific Garbage Patch has risen, floating creatures have declined.

In March, nearly 200 countries agreed to a new high seas treaty that will eventually allow the creation of protected areas in international waters. If garbage patches were so designated, the treaty could guard them against even well-intended human impacts, Helm says. An effort led by the government of Bermuda is advocating for the Atlantic Ocean’s Sargasso Sea, which also contains a garbage patch, to be named a marine protected area.

Doing so for other garbage patches could pause cleanup efforts long enough for scientists to better understand potential impacts, Helm says. Ultimately, groups may still decide to proceed with the cleanup. “Plastic is an invasive species,” Moore says. “Sometimes you have to kill invasive species to preserve biodiversity.”

Helm argues that the most effective solution is to prevent plastic from getting into the ocean in the first place by reducing our reliance on it. “Single-use plastic is the low-hanging fruit that should be the first to go.”

Removing trash from the ocean may not be as harmless as it seems. That’s the conclusion of new research, which finds that marine dumps known as “garbage patches” are home to countless delicate creatures that could perish when people scoop debris from the sea.

The oceans are home to five major garbage patches. They form far from land where strong currents swirl together, ferrying trash of all sizes. Some of it has been eroded by the churn into tiny debris known as microplastics.

The largest of these marine debris fields is known as the Great Pacific Garbage Patch. Spanning 1.6 million square kilometers midway between Hawaii and the coast of California, it was first observed in 1997 by Charles Moore, an oceanographer and founder of Algalita Marine Research and Education. The patch escaped notice for so long because most of its contents aren’t easily spotted from afar.

To see whether the Great Pacific Garbage Patch was harboring a cluster of floating creatures in addition to floating waste, a crew sailed through the patch for 80 days, collecting samples from Hawaii to the coast of San Francisco. “These mysterious regions are largely unexplored,” says Rebecca Helm, a biologist at Georgetown University.

The samples revealed high concentrations of three species that hover at the ocean’s surface. They included blue button jellies (jellyfishlike organisms that grow to about 3 centimeters wide), by-the-wind sailors (up to 10-centimeter-long creatures with translucent natural sails that help them drift in the wind), and violet snails (which float using bubbles and live in golf ball–size shells). Blue button jellies and by-the-wind sailors feed on plankton and serve as food for violet snails.

The scientists matched the locations of these creatures with high concentrations of plastic debris. That hints that ocean currents shepherd all of these floating objects—both life and trash—in the same way, the team reports this month in PLOS Biology.

Helm says the presence of these creatures implies a complex ecosystem in which they serve as food for predators like sea turtles and seabirds. “These animals don’t exist in isolation,” she says. “The food web they’re a part of affects the whole ocean.”

That could complicate efforts to clean up these patches. Some environmental organizations aim to remove the waste by skimming the surface with nets. But just as similar fishing methods lead to bycatch–creatures like dolphins caught accidentally while targeting commercial species such as shrimp–such cleanup efforts would likely scoop up surface-dwellers along with the debris, Helm says. Indeed, a modeling study published last month in Aquatic Biology found such efforts could potentially threaten the survival of species that have flourished for millions of years.

“I call it King Neptune’s nursery,” says Moore, who was not involved in either study. “Many creatures found there are delicate because they’re used to calm conditions.” Human activity could upset the balance, though Moore suggests the influx of plastic waste is already doing so. Based on his personal observations, as the volume of plastic in the Great Pacific Garbage Patch has risen, floating creatures have declined.

In March, nearly 200 countries agreed to a new high seas treaty that will eventually allow the creation of protected areas in international waters. If garbage patches were so designated, the treaty could guard them against even well-intended human impacts, Helm says. An effort led by the government of Bermuda is advocating for the Atlantic Ocean’s Sargasso Sea, which also contains a garbage patch, to be named a marine protected area.

Doing so for other garbage patches could pause cleanup efforts long enough for scientists to better understand potential impacts, Helm says. Ultimately, groups may still decide to proceed with the cleanup. “Plastic is an invasive species,” Moore says. “Sometimes you have to kill invasive species to preserve biodiversity.”

Helm argues that the most effective solution is to prevent plastic from getting into the ocean in the first place by reducing our reliance on it. “Single-use plastic is the low-hanging fruit that should be the first to go.”