Changes in the Toolik Lake Ecosystem of Alaska in the Past Decades

Abstract

Arctic regions are experiencing faster climate change than any other region in the world. Since the Arctic plays a critical role in the carbon cycle and strongly affects the thermal state of the surrounding permafrost, it is important to understand the impact of Arctic climate changes. This study investigates the climate and ecosystem changes of the Toolik Lake area in Alaska. Satellite remote sensing measurements and long-term baseline environmental and biological data from the Environmental Data Center (EDC) of the Toolik Field Station (TFS) were used to analyze this climate change and its impact on ecosystems. Land surface temperature (LST) data from the Terra/MODIS satellite remote sensing measurements show significant warming of the Toolik lake area in the past two decades, with an increasing trend of 1.049K/decade and 1.186K/decade for daytime and nighttime LST respectively. MODIS NDVI data during the summer season also shows a significant greening trend. EDC field observations show that air temperature above the Toolik lake has an increasing trend of 0.6762K/Decade from 1988 to the present, and 0.8598K/decade from 2000 to present, indicating that there has been faster warming in the past two decades. The thawing times of the Toolik Lake and the inlet river are becoming earlier, and the freezing times of the Toolik Lake and the inlet river are becoming later, causing the ice-free period of the lake to increase significantly. These changes have considerable impacts on local and regional ecosystems; for example, the first seen times of the Arctic ground squirrel around the study area are becoming earlier, and the hibernation periods are becoming shorter, as shown from the EDC field survey data. This study confirmed the rapid warming of Arctic regions and showed changes in the Toolik Lake ecosystem caused by climate change. In future research, these methods can be applied to other regions near the Arctic to gain further insight into changes in the Arctic regions caused by climate change.