Penguins have been pooping on Ardley Island off the coast of the Antarctic Peninsula for a long, long time. The population there is one of the biggest and oldest Gentoo penguin (Pygoscelis papua) colonies. But evidence from ancient excrement suggests that these animals didn’t always flourish.
Stephen Roberts of the British Antarctic Survey and colleagues set out to see how the Ardley population responded to past changes in climate to better inform future conservation efforts. The researchers studied the geochemical makeup of lake sediment samples and identified elements from penguin guano. Knowing the fraction of guano in lake sludge over time let the researchers track penguin population changes.
The Gentoo penguin colony was nearly wiped out three times over the 6,700 years that the penguins have occupied Ardley Island. But rather than lining up with changes in temperature or sea ice levels, these population dips corresponded to volcanic ash preserved in the geologic record from big eruptions of a volcano on nearby Deception Island. After each population crash, the colony took 400 to 800 years to recover, the team reports April 11 in Nature Communications.