Science Source

Decadal ecosystem response to an anomalous melt season in a polar desert in Antarctica

States that the McMurdo Dry Valleys (MDV) cold desert ecosystem is the largest ice-free area of Antarctica, comprising soils, glaciers, meltwater streams and permanently ice-covered lakes
Examines multi-decadal records, which indicate that the MDV exhibited a distinct ecosystem response to an uncharacteristic austral summer and ensuing climatic shift
Finds that a decadal summer cooling phase ended in 2002 with intense glacial melt (‘flood year’)—a step-change in water availability triggering distinct changes in the ecosystem
Finds that before 2002, the ecosystem exhibited synchronous behaviour: declining stream flow, decreasing lake levels, thickening lake ice cover, and more
Records show that since 2002, summer air temperatures and solar flux have been relatively consistent, leading to lake level rise, lake ice thinning and elevated stream flow
Findings suggest that even abrupt, short-lived climate events can cause long-term alterations in polar regions that subsequently change the overall trajectory of an ecosystem