School of Environmental and Forest Sciences, University of Washington, Seattle, WA 98195;
School of Environmental and Forest Sciences, University of Washington, Seattle, WA 98195.
Proc Natl Acad Sci U S A. 2021 Apr 13;118(15). doi: 10.1073/pnas.2021219118.
The highest concentration of the world's lakes are found in Arctic-boreal regions [C. Verpoorter, T. Kutser, D. A. Seekell, L. J. Tranvik, Geophys. Res. Lett. 41, 6396-6402 (2014)], and consequently are undergoing the most rapid warming [J. E. Overland et al., Arctic Report Card (2018)]. However, the ecological response of Arctic-boreal lakes to warming remains highly uncertain. Historical trends in lake color from remote sensing observations can provide insights into changing lake ecology, yet have not been examined at the pan-Arctic scale. Here, we analyze time series of 30-m Landsat growing season composites to quantify trends in lake greenness for >4 × 10 waterbodies in boreal and Arctic western North America. We find lake greenness declined overall by 15% from the first to the last decade of analysis within the 6.3 × 10-km study region but with significant spatial variability. Greening declines were more likely to be found in areas also undergoing increases in air temperature and precipitation. These findings support the hypothesis that warming has increased connectivity between lakes and the land surface [A. Bring et al., J. Geophys. Res. Biogeosciences 121, 621-649 (2016)], with implications for lake carbon cycling and energy budgets. Our study provides spatially explicit information linking climate to pan-Arctic lake color changes, a finding that will help target future ecological monitoring in remote yet rapidly changing regions.
世界上湖泊最集中的地区位于北极-北方地区[C. Verpoorter、T. Kutser、D. A. Seekell、L. J. Tranvik，《地球物理研究快报》41，6396-6402（2014）]，因此这些地区正在经历最迅速的变暖[J. E. Overland 等人，《北极报告卡》（2018）]。然而，北极-北方湖泊对变暖的生态响应仍然高度不确定。遥感观测到的湖泊颜色的历史趋势可以提供对不断变化的湖泊生态系统的深入了解，但尚未在全北极范围内进行研究。在这里，我们分析了来自 Landsat 30 米的 30 米生长季节合成物的时间序列，以量化北美北极和北方西部 4×10 多个水体的湖泊绿色度的趋势。我们发现，在研究区域内的 6.3×10 公里范围内，从分析的第一个十年到最后一个十年，湖泊的绿色度总体下降了 15%，但具有显著的空间变异性。在空气温度和降水同时增加的地区，绿色化下降的可能性更大。这些发现支持了变暖增加了湖泊与陆地表面之间连通性的假说[A. Bring 等人，《地球物理研究：生物地球科学》121，621-649（2016）]，这对湖泊碳循环和能量预算都有影响。我们的研究提供了将气候与全北极湖泊颜色变化联系起来的空间明确信息，这一发现将有助于在偏远但变化迅速的地区确定未来的生态监测目标。
