Details

Autor(en) / Beteiligte

• Yang, Xiao
• O’Reilly, Catherine M.
• Gardner, John R.
• Ross, Matthew R. V.
• Topp, Simon N.
• Wang, Jida
• Pavelsky, Tamlin M.

Titel

The Color of Earth’s Lakes

Ist Teil von

• Geophysical research letters, 2022-09, Vol.49 (18), p.n/a

Ort / Verlag

Washington: John Wiley & Sons, Inc

Erscheinungsjahr

2022

Quelle

Wiley-Blackwell Journals

Beschreibungen/Notizen

• 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. Plain Language Summary Water color is a reasonable approximation of water quality. Scientists have studied lake water color for over a century, but we still do not know the color of the lakes across the whole Earth. We used satellite images to determine the water color of 85,360 lakes found around the world. We found that most lakes look green or brown. Blue lakes are not very common. Blue lakes are found in places where the summer temperatures are cooler. Blue lakes are also likely to be covered by ice in winter and are generally deeper than lakes that have green or browner water colors. So, if the summer temperatures get warmer or winter temperatures get so warm that there is no more lake ice, some lakes that are currently blue might shift to being green or brown. Projecting into the future, we predict that 1 in 10 blue lakes might change color because of warming air temperatures. These changes in water color probably indicate a change in the water quality and the conditions for fish in those lakes. We can use satellite images to track changes in lake water color into the future to help us understand how water quality is changing. Key Points ∼5.14 million satellite observations over 2013–2020 capture the most common water color for 85,360 global lakes and reservoirs Lake color shows strong bimodal distribution, with blue lakes clustered spatially and non‐blue lakes more wide‐spread at global scale Climate and lake properties influence global patterns in lake color, suggesting blue lakes may become less abundant with climate change