The continent, a researcher said, is the “ideal experimental lab,” for studying how nutrients relate to an ecosystem’s biodiversity.
We tend to appreciate penguins for their cuteness. But to the natural world, it’s their poop that matters.
According to research, published Thursday in the journal Current Biology, penguin and elephant seal excrement fosters biodiversity across Antarctica.
Despite the cold, dry weather, the nitrogen in the animals’ waste provides nutrients that are otherwise unavailable in this stark setting, said Stef Bokhorst, the paper’s lead author and a polar ecologist with the Vrije Universiteit Amsterdam in the Netherlands.
“If you put more poo in the system, the Antarctic wildlife like that,” he said.
[Like the Science Times page on Facebook. | Sign up for the Science Times newsletter.]
Because it’s so consistently cold, Antarctica is challenging to study, and it’s been difficult to predict patterns of biodiversity. But Dr. Bokhorst and his colleagues managed to find a direct connection between areas of biodiversity — filled with lichens, mosses, microscopic animals and small creatures — and the nitrogen left behind when penguins and elephant seals defecate.
The larger the penguin colony, the further its footprint spread, the study showed.
The team looked at nitrogen because its various isotopes made it relatively easy to trace it from the sea to mosses and lichen that grow on land, and to the animals that feed on them. The penguins and elephant seals were the conduits ferrying that nitrogen from water to land, the study showed.
“We know that nutrient content of your food has a big impact on abundance and diversity of consumers, but for whatever reasons, no one’s looked at that in such a cold place as the Antarctic,” Dr. Bokhorst said.
The continent, he said, is the “ideal experimental lab,” for studying how nutrients relate to an ecosystem’s biodiversity because its food web is relatively simple. In a more habitable place, there are so many interacting factors that it’s often difficult to figure out what’s driving what — whether predation or more nutrients are leading to changes, for instance, Dr. Bokhorst said. In the new study, it was not hard to trace the path of the nitrogen from penguin and elephant seal to lichen and moss and then to mites and worms.
Dr. Bokhorst is now studying invasive species in the Arctic and Antarctic, mostly spread, he said, by the boots of tourists hoping to catch a glimpse of penguins. Waste from penguin colonies then nourishes those invasive species, which consist mostly of grasses. “These animals could be like invasion engineers,” allowing the grasses to spread further, Dr. Bokhorst said.
One bit of good news from his research: Although Dr. Bokhorst and his colleagues have been looking for more than 15 years, they have yet to see any negative effects from climate change in the areas they’ve studied. Penguins may shift their feeding grounds to keep up with the food supply, but “the vegetation seems to be able to cope with a couple of degrees of warming,” he said.
Earlier reporting on penguins