The Color of Earth’s Lakes

Abstract

Although water color is a fundamental property of freshwater ecosystems, the global distribution of lake color remains unknown. Here, we used 5.14 million color records derived from satellite images during 2013–2020 to determine the modal water color of 85,360 representative lakes worldwide. We find that globally, lake modal colors span the visible spectrum with a bimodal distribution of blue versus non‐blue (green‐brown), with 31% of lakes being blue and 69% being non‐blue. Both climate and lake morphology influence lake modal color. Blue lakes are associated with cooler summer air temperature, winter ice cover, and higher precipitation. Under a 3°C increase in summer air temperature, 14% of blue lakes could shift to a non‐blue regime, representing a substantial change to their underlying ecology. As lake ecosystems continue to face a range of stressors, this study provides a critical baseline for understanding lake responses to global environmental change.

Shifts, Trends, and Drivers of Lake Color Across China Since the 1980s

“…However, Yang et al. (2022) found that increasing summer temperatures in the future would induce more green and brown lakes. Our analysis showed the contribution of air temperature to the shifts did not cause differences in raising or reducing $${\lambda }_{d}$$ (Figures 3b and 3c), suggesting that the bluing lakes possibly resulted from multiple factors rather than only temperature.…”

“…For example, oligotrophic lakes were usually blue, eutrophic lakes greener, and eutrophic lakes with high suspended sediment were usually brown. It should be noted that $${\lambda }_{d}$$ has limited information in determining constituent concentrations compared to hyperspectral measurements, though it has been used to reveal patterns and trends in water color (Gardner et al., 2021; Giardino et al., 2019; Topp et al., 2021; Yang et al., 2022).…”

“…We first examined the trends of lake color in chromaticity color space and identified the prevalence of shifts of lake color in China. It is hypothesized that the patterns of lake color change as a result of climate change and human activity (Hou et al., 2017; Kuhn & Butman, 2021; Oleksy et al., 2022; Yang et al., 2022). Therefore, we studied possible links between air temperature, wind speed (WS), precipitation, land use, and vegetation cover and lake color.…”

“…However, in situ data series are rare and available only in a few lakes, limiting further understanding of changes in lake color over regions (Stanley et al., 2019). Satellite images have been utilized to investigate spatial distributions of lake color (Giardino et al., 2019; Lehmann et al., 2018; Topp et al., 2021; Yang et al., 2022). However, temporal shifts and trends in lake color and relevant drivers are rarely documented (Kuhn & Butman, 2021; Lehmann et al., 2019; Oleksy et al., 2022).…”

Assessing and predicting the influence of chromophoric dissolved organic matter on light absorption by phytoplankton in boreal lakes

“…While the browning increases water color and can reduce light availability, the increased input of allochthonous matter also provides nutrients, which can promote phytoplankton biomass and thus help to compensate for the light limitation (Corman et al 2018). As brown lakes are projected to become more common in the future (Yang et al 2022), it will be useful to understand the effect of browning on the light availability to phytoplankton.…”