Potential Influence of Climate Change on the Acid-Sensitivity of High-Elevation Lakes in the Georgia Basin, British Columbia

Donna Strang,Julian Aherne

doi:10.1155/2015/536892

Abstract

Global climate models predict increased temperature and precipitation in the Georgia Basin, British Colmbia; however, little is known about the impacts on high-elevation regions. In the current study, fifty-four high-elevation lakes (754–2005 m a.s.l.) were studied to investigate the potential influence of climate change on surface water acid-sensitivity. Redundancy analysis indicated that the concentration of nitrate, dissolved organic carbon, and associated metals was significantly influenced by climate parameters. Furthermore, these components differed significantly between biogeoclimatic zones. Modelled soil base cation weathering for a subset of the study lakes(n=11)was predicted to increase by 9% per 1°C increase in temperature. Changes in temperature and precipitation may potentially decrease the pH of surface waters owing to changes in anthropogenic deposition and organic acid production. In contrast, increased soil base cation weathering may increase the critical load (of acidity) of high-elevation lakes. Ultimately, the determining factor will be whether enhanced base cation weathering is sufficient to buffer changes in natural and anthropogenic acidity. Mountain and high-elevation regions are considered early warning systems to climate change; as such, future monitoring is imperative to assess the potential ramifications of climate change on the hydrochemistry and acid-sensitivity of these surface waters.

Highlights

It is widely accepted that changes in climate may significantly alter the biological, physical, and chemical systems of mountainous regions [1,2,3]
The CGCM2 model predicted that both air temperature and precipitation will increase in the Georgia Basin under the Intergovernmental Panel on Climate Change (IPCC) A2 scenario; the average increase in mean temperature from present day at the study catchments was 1.1, 2.1, and 3.4∘C for the years 2020, 2050 (Figure 2, [18]) and 2080, respectively
It is difficult to predict how the hydrochemistry of surface waters will be influenced by climate change

Summary

Introduction

It is widely accepted that changes in climate may significantly alter the biological, physical, and chemical systems of mountainous regions [1,2,3] Their potentially dramatic response has been attributed to the pronounced rise in temperature (1.5– 2.0∘C during 1980 to 1995) in high-elevation regions compared with the global average (0.5∘C; [4]) and to the influence of changes in glacier, ice, and snow cover [5]. Experimental climate change treatments in regions of the Rocky Mountains, USA, have shown that changes in snow pack cover significantly influence the mineralization rate of both nitrogen (N) and carbon [10]. These changes in nutrient hydrogeochemistry have been associated with altered plant community competition, species dominance, and their geographical range [11]

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Conclusion