It is one of a chain of uninhabited islands and atolls that extent 1,200 miles northwest of the main Hawaiian Islands. Two years ago, I got the opportunity to visit this remote island as part my job with the U.S. Fish and Wildlife Service.

Lisianski (Lee-see-an-ski) itself is small, with a sand beach around the perimeter and shrubs, grasses, and a few trees covering the interior. It required about two hours to walk around the entire island, something that we did every day.

We encountered lots of wildlife on these walks: Hawaiian monk seals, sea turtles, and thousands of birds of all shapes and sizes including terns, shearwaters, petrels, albatross, boobies and frigate birds. Every square foot of the island contained somebody's nest, either above ground or below ground.

In an act of great foresight, President Theodore Roosevelt protected all these islands 100 years ago as the Northwest Hawaiian Islands National Wildlife Refuge. Despite their remoteness, sealers, whalers, feather hunters and guano miners all threatened the marine life and bird life of these islands at that time.

Monk seals were killed for their meat, oil and skin. Plume hunters slaughtered birds by the boatload to satisfy the demand for feathers in ladies' hats. Rabbits accidentally released on Lisianski completely denuded the island of vegetation by 1915.

Thankfully, the rabbits are gone, and the marine life, the birds and the vegetation are mostly flourishing again. It's a testimony to the resiliency of nature.

But the island's history is also a testimony to the fragility of ecosystems and how vulnerable these places can be. Consider that fashion trends in the U.S. and Europe in the early part of the 20th century were inadvertently wiping out wildlife resources on the other side of the world. Rabbits were not introduced deliberately to denude Lisianski but that was the unintended consequence of them being there.

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It is often our lack of appreciation or understanding that threatens ecosystems. Hawaiian monk seals and sea turtles are threatened by abandoned fishing nets, pollution, habitat loss, loss of food resources and illegal hunting. Coral reefs near Lisianski and around the world are threatened by warming sea temperatures.

The islands themselves are at risk of disappearing due to rising sea levels. Most of us don't connect bleached corals and flooded islands every time we start our vehicles, but that is an indirect result of this everyday routine.

On Lisianski, not only did we come across birds, sea turtles and monk seals on our daily walks, but we also found something else – garbage – piles of litter and debris that had washed up onto the beach over the years. It was astonishing. The island is almost 1,000 miles away from the nearest human habitation and there was garbage everywhere: bottle caps, cigarette lighters, plastic containers, glass bottles with labels in many different languages, balls, fishing nets, chairs, buckets, and all kinds of other plastic debris.

Floating garbage is a problem for beaches all over the world but the difference on Lisianski is that no one is around to remove it. The seabirds on Lisianski and elsewhere often ingest this floating debris at sea, mistaking it for food. They can accumulate so much indigestible trash in their stomachs that they starve to death.

We found the tragic evidence of these birds around the island – just a small, jumbled mass of decaying bones, feathers, and plastics.

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Not all of the stranded garbage we encountered was unsightly. Some of what accumulated on the beach were glass fishing floats that had drifted to the island from Asian fishing nets deployed half an ocean away. Amazingly, these fragile-looking glass balls remain intact throughout their journey across the Pacific, a journey requiring at least 10 years.

I returned home with a collection of these glass floats and this past Earth Day, I found myself contemplating them with a sense of awe.

To me, they are marvelous symbols of the earth. Most obviously, their shape resembles the spherical body of our planet. Their color reflects the oceans that comprise 70 percent of our planet's surface. Their composition represents both the strength and ultimate fragility of ecosystems on our planet. They are surprisingly strong but hit them hard enough, and they will break. Their translucent and opaque qualities reflect the complex and sometimes obscure relationships that connect all life on the planet.

Objects viewed through the molded glass can appear distorted or unclear, just as our understanding of ecological interactions can be muddled or incorrect.

Finally, their origin, most likely Japan, serves as a reminder of how small a planet we live on and how easily we can affect it. Seemingly trivial actions, such as buying a feather hat, discarding a cigarette lighter, or driving an automobile, can have unintended consequences that reach around the globe.

I don't really know what motivated Theodore Roosevelt to protect these islands. But I believe that as humans, we all share a responsibility to protect the planet. That responsibility entails recognizing how we affect resources worldwide through our actions and lifestyle choices and then working to lessen those impacts.

Collectively, these small efforts to reduce our individual, ecological footprints will have a global impact and will help preserve special places like Lisianski forever.