This is an interesting story from my favorite part of the world: why did this lake at the top of a once-dormant volcano suddenly turn red? Is this the result of a chemical reaction? (That's my guess).
Volcanologists were puzzled today about why a lake atop a rumbling volcano on the South Pacific island of Ambae has changed color from blue to bright red.
Mount Manaro, one of four volcanos currently active in the island nation of Vanuatu, has been showing signs of erupting for only the second time in 122 years.
.
- Log in to post comments
Might be a biological. Some forms of dinoflagellate or bacteria can turn water red.
Yup, red tide was my first thought. Changes in the temperature or salinity of the water might allow for algae blooms. I don't know enough about the lake, though, to know if that's even a possibility.
If it is a dinoflagellate or algae it will only be a temporary change. We can wait and see.
Scanning some abstracts, the lake may have been stratified, waters going anoxic not far beneath the surface. Turnover would have mobilised nutrients for a bloom.
I would agree with GrrlScientist that it is a chemical reaction. If the volcanic activity suddenly overturned previously stable layers of water in the crater, and if iron rich water was exposed to mixing and oxygen, the iron would oxidize turning the water red. This happened in the volcanic Lake Nyos in Cameroon in 1986 after the lake belched forth a huge amount of carbon dioxide suffocating thousands of people and animals near the lake. After this limnic eruption, the lake turned deep red as iron rich waters moved from a reducing environment to an oxidizing one.