It's estimated that roughly 8 million metric tons of plastic enters the world's oceans each year — a tragic influx that is posing serious threats to marine life.

Besides the Great Pacific Garbage Patch, the most direct way to view the impact of all this garbage is to gaze into the stomachs of marine fish, whales and birds. Researchers studying 13 sperm whales that washed up on the coast of Schleswig-Holstein in Germany recently discovered this firsthand, with four of the mammals having very large quantities of plastic in their stomachs.

Included in the sad inventory of items recovered was a 42-foot-long commercial fishing net, a 27-inch plastic cover for a car engine, and the jagged-edged remains of a plastic bucket.

Absolutely tragic.

sperm whales plasticResearchers hold some of the large items recovered from four of the thirteen sperm whales' stomachs. (Photo: Claußen/LKN.SH)

"These findings show us the effects of our plastic society," Robert Habeck, the environment minister of Schleswig-Holstein, said in a statement. He added that marine animals inadvertently consume plastic, with many suffering the consequences, or worse, slowly dying. "Some starve with full stomachs," he said.

The presence of plastic itself in the diets of marine life is sadly becoming more pervasive. A study published last year using 76 fish from Indonesian seafood markets and 64 from markets in California found roughly a quarter had either plastic fragments or textile fibers in their guts.

As for the deceased sperm whales, while the four whales with plastic in their stomachs undoubtedly felt discomfort from the items, the researchers suspect the pod died of starvation after chasing food into shallow waters. Once trapped, the weight of their bodies pressed together blood vessels, lungs and other organs, leading to acute cardiovascular failure.