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Hoboro Island off the coast of Japan may soon be an island of the past, and it’s primarily due to one unsuspecting isopod.

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Hoboro Island off the Coast of Horoshima Japan was never very big, but folks have noticed that it is slowly shrinking. The island was 22 meters high in 1928, but it's only 6 meters high today.

It's not clear how long it has left, but some people have guessed it could disappear in the next century. And it is not being worn away by the wind or the waves, at least not directly. Now I'm gonna guess that you're not gonna predict this: the island is literally being eaten by bugs.

Actually, not bugs precisely. They are small crustaceans related to wood lice called "sphaeroma sieboldii". Researchers believe they bore holes into rock to protect their mates and eggs.

And these little holes expedite natural erosion from water, which breaks off pieces of the island and then washes them away. While there does not seem to be a ton of research about Hoboro specifically, the phenomenon of bioerosion is actually pretty well studied in general. And it's worth understanding because it doesn't just come for small rocky islands off the coast of Japan, but for whole ecosystems.

The perpetrators may include creatures from animals to plants to microbes, who bite, burrow, or chemically dissolve anything from wood to coral, and even solid rock.  Plant roots can fracture rocks apart. Microbes and fungi break down minerals in soils. Even the footfalls of penguins wear down the bedrock of islands.

Around the world, there are tons of examples of bioerosion.  An isopod closely related to those on Hoboro Island can bore centimeters deep into sandstone in Malaysia and remove up to 50 percent of the surface from rocks next to the sea. Isopods like these also chomp down on plant roots, wooden structures, and deck floats, this can cause chaos for humans and even creates microplastic pollution. One of the environments where bioerosion has the biggest impact is coral reef ecosystems, so they're also the biggest targets of study compared to unique scenarios like Hoboro.

Certain sea urchins, sponges, and fish such as parrotfish, all graze on the coral structures that form the reef. A single parrotfish can erode over a thousand kilograms of coral per year. In a way human tourists benefit from this.

Bioeroders help break reefs down into sand which forms the idyllic white sand beaches on nearby tropical islands. However, there is a delicate balance between erosion and accumulation of coral. As the climate crisis acidifies the oceans, the balance tips toward erosion.

Scientists expect climate change to also increase severe weather events which could increase many types of erosion, including in spots expedited by bioerosion. Human pollution, hunting and harvesting of animals as well as introduction of invasive species, all can alter the abundance of bioeroders. And all this makes it extremely important to understand bioerosion if we want to conserve these habitats as the climate crisis rages on.

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