Arctic climate shifts drive rapid ecosystem responses across the West Greenland landscape

Prediction of high latitude response to climate change is hampered by poor understanding of the role of nonlinear changes in ecosystem forcing and response. While the effects of nonlinear climate change are often delayed or dampened by internal ecosystem dynamics, recent warming events in the Arctic have driven rapid environmental response, raising questions of how terrestrial and freshwater systems in this region may shift in response to abrupt climate change. We quantified environmental responses to recent abrupt climate change in West Greenland using long-term monitoring and paleoecological reconstructions. Using >40 years of weather data, we found that after 1994, mean June air temperatures shifted 2.2 °C higher and mean winter precipitation doubled from 21 to 40 mm; since 2006, mean July air temperatures shifted 1.1 °C higher. Nonlinear environmental responses occurred with or shortly after these abrupt climate shifts, including increasing ice sheet discharge, increasing dust, advancing plant phenology, and in lakes, earlier ice out and greater diversity of algal functional traits. Our analyses reveal rapid environmental responses to nonlinear climate shifts, underscoring the highly responsive nature of Arctic ecosystems to abrupt transitions

The Arctic in the twenty-first century: changing biogeochemical linkages across a paraglacial landscape of Greenland

The Kangerlussuaq area of southwest Greenland encompasses diverse ecological, geomorphic, and climate gradients that function over a range of spatial and temporal scales. Ecosystems range from the microbial communities on the ice sheet and moisture-stressed terrestrial vegetation (and their associated herbivores) to freshwater and oligosaline lakes. These ecosystems are linked by a dynamic glacio-fluvial-aeolian geomorphic system that transports water, geological material, organic carbon and nutrients from the glacier surface to adjacent terrestrial and aquatic systems. This paraglacial system is now subject to substantial change because of rapid regional warming since 2000. Here, we describe changes in the eco- and geomorphic systems at a range of timescales and explore rapid future change in the links that integrate these systems. We highlight the importance of cross-system subsidies at the landscape scale and, importantly, how these might change in the near future as the Arctic is expected to continue to warm

Factors Controlling Methane in Arctic Lakes of Southwest Greenland - Fig 3

<p>Regional differences in (a) chloride (Cl), (b) sodium (Na), (c) calcium (Ca), (d) magnesium (Mg), and (e) DOC in lakes across southwest Greenland. Bars represent 1 SE of the mean, and letters represent significant differences (p < 0.05) based on post-hoc comparisons of ln-transformed data.</p

Individual relationships between predictors of methane (CH₄) in Greenland lakes.

<p>All lines represent significant regression models. Statistics for each relationship can be found in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0159642#pone.0159642.t003" target="_blank">Table 3</a>.</p

Methane concentrations (μmol L^-1) across the study region in southwest Greenland.

<p>Methane concentrations (μmol L^-1) across the study region in southwest Greenland.</p

Characteristics of the 15 lakes used in this study.

<p>Characteristics of the 15 lakes used in this study.</p

Temperature differences across the ice-free season of summer 2014 in southwest Greenland lakes, including differences in depth and regions.

<p>Bars represent 1 SE of the mean. Statistics outlining differences among groups may be found in the text.</p

Lake characteristics for pilot lakes sampled in 2013.

<p>Lake characteristics for pilot lakes sampled in 2013.</p

Patterns in lake-water methane and sulfate concentrations across the sampling region from the Greenland Ice Sheet outward in 2014.

<p>Patterns in lake-water methane and sulfate concentrations across the sampling region from the Greenland Ice Sheet outward in 2014.</p

Regression results for predicting methane (CH₄) in southwest Greenland lakes, along with the validation of this model using 2013 pilot lake data.

<p>Regression results for predicting methane (CH₄) in southwest Greenland lakes, along with the validation of this model using 2013 pilot lake data.</p