View Images Gentoo penguins climb up a snowy slope on Danco Island in the Western Antarctic Peninsula on March 14, 2016; Photograph by Carolyn Van Houten

9 a.m. local time, March 14, 2016, Post #3

A flurry of snowflakes swirls past in the cold morning air—at least they look like snow—but I soon realize they’re actually penguin feathers, lofted by wind from the colony of stinky birds nesting a few yards away.

It is late summer on Danco Island, a small postage stamp of land just off the coast of Antarctica. I had just climbed off a Zodiac, waded in tall rubber boots through a foot of frigid sea water, and then scrambled ashore. It was our first time setting foot on land since sailing across the Drake Passage from Argentina to the Antarctic Peninsula–a journey that took three days. After all of that, this first step onto land was hard-won. It involved climbing onto an overhanging platform of ice, several feet thick, which covered this part of the island.

Between 500 and 1,000 gentoo penguins live on the mostly bare, rocky, northwestern half of Danco Island. As I walk across the ice platform that I climbed onto, it becomes clear that these penguins have made themselves at home here. The restless waddling and sliding of these 18-inch birds has worn grooves two feet deep into the ice–creating a penguin highway that leads down to the beach.

Melted into the surface of the ice here and there are straight yellow or orange lines, each a couple feet long–evidence that despite its small stature and low undercarriage, the gentoo penguin can pee like a race horse.

I climbed 400 feet up the rocky mountain at the island’s center, past one group of penguins after another. The little birds stood upright among the rocks, as though dressed in black tie formal, waiting for something. (But what?) Off to the left, a lone penguin waddled patiently up the mountain on a snowfield–one that was steep and icy enough that I wouldn’t wander onto it myself without an ice ax and crampons.

The entire island, up and down the mountain, was littered with penguin feathers, straight and narrow like cactus needles, sometimes an entire clump of them. What was most striking, though, was the dirt. Here and there, the moist, brown soil was mushed in between the rocks. It looked as though it had recently come out the rectum of a penguin–which was probably pretty close to the truth. Of everything I saw on Danco Island, it was this dirt, this penguin poo, that most captured my imagination.

Danco is a low island with a single rounded mountain, evidence that glaciers bulldozed over it during the last ice age. When the glaciers finally retreated 5,000 or 10,000 years ago, they left the island denuded, stripped of soil–smooth rock littered with glacially pulverized sand. These gentoo penguins are now helping to reverse the process, turning this rocky postglacial wasteland into an environment that will one day be suitable for many kinds of plants and animals that don’t currently live here.

Every summer and fall for the last 5,000 years or so, penguins living on Danco have dived into the water, eaten krill, then returned to the island and pooped out the remains of those meals. In doing so, they acted as a bucket brigade, ferrying up tons of nutrients derived from plankton and krill in the ocean, and dropping it onto the rocky island.

If that sounds a little far-fetched, then consider a simple back-of-envelope calculation: say that an average of 500 penguins has pooped on the island 100 days per year, for the last 5,000 years. Two biologists sitting next to me in the ship’s cocktail lounge tonight estimated that a typical gentoo might drop around two thirds of a Coke can of poop each day (call it 30 milliliters). Crunch all of these numbers together, and you find that the gentoo penguins on Danco are probably dumping over 3,000 pounds of poop on the island each year. Over the last 5,000 years they may have delivered over 16 million pounds of poop onto the island. That translates into thousands of pounds of critical plant nutrients like nitrogen and phosphorus–and far more organic carbon than that. Importantly, all of these nutrients are derived from the ocean–from krill and from plankton–and would never have gotten onto Danco Island had penguins and other sea animals not brought them there.

This could set the stage for new types of plants and animals to arrive and spread on the Antarctic Peninsula as temperatures continue to rise. If you exclude seals, penguins, and flying birds that spend some of their time on land, the Antarctic Peninsula’s land is inhabited by only a few readily recognizable living things: lichens and moss that grow on rocks, near-microscopic worms, tiny mites, and 6-legged animals called tardigrades that can be smaller than the period at the end of this sentence. It’s a fragile ecosystem, long separated from the rest of the world.

But newcomers are arriving. At least one type of grass has already found its way to the Antarctic Peninsula–possibly hitchhiking in as a stray seed on a boot. Insects from other continents have also found their way down. As the Peninsula warms, these outside species will all the more readily arrive, survive, and establish themselves in Antarctica. Those penguins, long laboring to carry nutrients from the ocean to land, are already creating landing pads up and down the coast of the peninsula where the newcomers can gain a foothold.