Research press release


Nature Communications

Environmental sciences: Volcanic eruptions sealed penguins' fate



今回、Stephen Robertsたちの研究グループは、アードレイ島の中央部にある湖の堆積層に長い年月をかけて蓄積されたペンギンのグアノ(排泄物が堆積固化した物質)から見つかった生物地球化学的特徴に基づいて約7,000年間のペンギンの個体数の記録を再構築し、情報不足の問題に取り組んだ。その結果、Robertsたちは、ペンギンのコロニーに最も大きな影響を及ぼしたのが気温や海氷状態の変化ではなく、近くにあるデセプション島での火山の爆発的噴火であり、火山灰が地表を覆い、少なくとも3回はコロニーの放棄に追い込まれたことを発見した。さらに、このグアノの記録からは、コロニーがこうした火山噴火から持続可能な回復を遂げるまでに400~800年かかったことも明らかになった。

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.

doi: 10.1038/ncomms14914

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