EVIDENCE OF CRITICAL SLOWING DOWN AND FLICKERING IN LONG TERM BIOMASS, PRODUCTIVITY AND DIVERSITY TRENDS IN TAYLOR VALLEY LAKES, MCMURDO DRY VALLEYS, ANTARCTICA

While many of the effects that polar regions have been experiencing from decades of warming temperatures and increased thaw have been documented, biological impacts in the McMurdo Dry Valleys, Antarctica have been difficult to discern. The lakes of the McMurdo Dry Valleys provide a unique system in which to study ecosystem responses to climate change. Three decades of intensive study by the McMurdo Long Term Ecological Project has documented physicochemical and biological trends in Taylor Valley Lakes Fryxell, Hoare and Bonney. Subtle climatic changes over the same period, combined with uncoupled dynamics between biomass, productivity and disturbances have made it difficult to distinguish stochastic biological variation from a critical transition that may represent a new state for these lakes. Long term trends in biomass, productivity and microbial diversity [jp1] reveal that Taylor Valley lakes may be approaching a critical biological transition, as evidenced by increased recovery time after disturbance (critical slowing down) and increasing shifts between alternate states (flickering). Such dynamics provide metrics of lake physical or biological stability, enable us to infer the magnitude of disturbance required for a critical state change in the lakes, and predict the impact of future climatic changes on lake biota.

Primary Presenter: Cristina Takacs-Vesbach, University of New Mexico (cvesbach@unm.edu)

Authors:

Cristina Takacs-Vesbach, University of New Mexico  (cvesbach@unm.edu)

Jade Lawrence, University of New Mexico  (jlawrence1@unm.edu)

Emily Reynebeau, University of New Mexico  (ereynebeau@unm.edu)

Renee Brown, University of New Mexico  (rfbrown@unm.edu)

Rachael Morgan-Kiss, Miami University of Ohio  (morganr2@miamioh.edu)

John Priscu, Montana State University  (jpriscu@montana.edu)