One of the oldest and largest gentoo penguin colonies on the Antarctic Peninsula was periodically wiped out by an erupting volcano according to an article published in Nature Communications this week. The findings reveal at least three local near-extinction events over the past 7,000 years, from which it took the colony between 400 and 800 years to recover.
Ardley Island off the northern coast of the Antarctic Peninsula is home to a large and diverse colony of penguins. However, warming conditions and changes in sea-ice extent are threatening this diversity, with the gentoo population growing while the Adelie and chinstrap penguins decline. Unfortunately, our understanding of how this colony has changed in the past, and thus our ability to project future changes, is restricted by a lack of long-term records.
Stephen Roberts and colleagues attempted to address this gap in knowledge by reconstructing a 7,000-year-long record of penguin population based on biogeochemical signatures recovered from penguin guano that had accumulated over time in the sediments of the island's central lake. The authors discovered that rather than changing temperatures and sea-ice conditions, explosive eruptions of the volcano on nearby Deception Island had the most dramatic impact on the penguin colony, with blankets of ash resulting in colony abandonment on at least three occasions. The guano record further reveals that sustainable colony recovery lagged these eruptions by 400-800 years on average.