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Why Do Some Lakes Change Color From Blue to Pink During Dry Seasons?
为什么一些湖泊在干旱季节会从蓝色变成粉红色？
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Certain shallow lakes turn pink when evaporation concentrates salts and triggers microbial blooms.
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Specialized archaea and algae, like Dunaliella salina, produce red carotenoid pigments under high-salt stress.
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These microbes thrive where salt levels exceed 15%, far above normal seawater concentration.
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Sunlight exposure and warm temperatures further boost pigment production during dry months.
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The color intensifies as water volume shrinks and light reflects off dense microbial layers near the surface.
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Lake Hillier in Australia and Lake Retba in Senegal show this phenomenon seasonally.
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No toxic chemicals cause the shift — it is entirely natural and reversible with rainfall.
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Scientists study these lakes to understand life limits in extreme environments on Earth and Mars.
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The pink hue does not indicate pollution but rather a delicate ecological balance of salinity and biology.
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When rain refills the lake, dilution returns it to pale blue or green within weeks.