Earth Matters: Henderson Island reflects overall garbage trouble in oceans

Already threatened by rising sea levels from global temperature increases, the world’s islands are also threatened by another scourge of modern society — trash.

While ocean-going trash is a problem all around the world, the problem is especially appalling in the center of the ocean’s massive water circulation currents. Thanks to the unique pattern of ocean water circulation, this trash has accumulated in higher concentrations in massive “Garbage Patches” near the middle of the major oceans of the world. In the Atlantic and Pacific, one is found north of the equator and another in the Southern Hemisphere.

The impact of this trash, then, is particularly serious on the shores of islands near the center of these circulation cells. One near the center of the South Pacific Gyre is now being called the most polluted shore on Earth. A British Overseas Territory by the name of Henderson Island, the six-by-three-mile island is about halfway between Chile and New Zealand. It’s part of the Pitcairn Island Group, and like two of the other three islands in the small chain, Henderson is uninhabited.

Henderson Island is one of over 27,000 islands in the Pacific Ocean, and like the overwhelming majority, it owes its existence to one of the tens of thousands of volcanic peaks that have arisen from the geologically violent Pacific Ocean basin.

Recognized by many oceanographers as a horribly polluted island, University of Tasmania researcher Jennifer Lavers took a team there in 2015 to study the scope and effects of the litter. Her final report was published this past week in the “Proceedings of the National Academy of Sciences.”

They estimated the island was covered by approximately 38 million pieces of trash, the overwhelming majority of it made of plastic. Among the wide variety of items found by Lavers’ team was a red Monopoly hotel and green plastic toy soldiers like her brother played with as a kid. Yes, as cartoon character Pogo noted, we have once again met the enemy, and he is us.

Among the oddities discovered by the research team was a turtle that died after being trapped in an old fishing net and a hermit crab living in a cosmetics container instead of an old shell. They estimated the accumulated weight of the litter was nearly 18 tons — on an island that has no record of any human habitation. With the constant ebb and flow of ocean waves, most of the trash was partially buried in the (otherwise) sandy shoreline sediment.

After determining the initial estimates of accumulated trash, Lavers wanted to determine how much trash collected on the shores of Henderson Island each day. The team cleared a 10-meter stretch of the beach and then waited for a fresh batch of litter to be deposited. One day of that study saw 268 new pieces of garbage in that section alone. Extrapolated for the entire island, Lavers estimated 13,000 new pieces of litter come ashore each day.

Lavers had these words of wisdom: “We need to drastically rethink our relationship with plastic. It’s something that’s designed to last forever, but is often only used for a few fleeting moments and then tossed away.”

John Frederick writes on environmental issues every other Saturday. You can read about Dr. Lavers’ research on the National Academy of Sciences website.

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