Millennium-scale volcanic impact on a superhumid and pristine ecosystem

Abstract

Ecosystems damaged by distal volcanic ash and sulfur deposition usually recover within decades. However, sediment, stalagmite, and pollen records from the southernmost Andes indicate a 2000 yr impact on forest and aquatic ecosystems after deposition of a thin tephra layer. SO 2 released from altering pumice produced intense soil and lake acidification in a >150,000 km 2 area. Acidification led to nutrient leaching and affected soil microorganisms, causing plant decay and increased soil erosion in an area larger than 8000 km 2 . We conclude that weakly buffered soils in humid environments are extremely vulnerable to volcanic and anthropogenic acidification, causing long-lasting ecosystem damage and perturbations of paleoclimate proxy records.