Where on Earth: Floating Islands in India

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What are the round, green spots in this satellite image?

Produced by the Space Telescope Science Institute’s Office of Public Outreach in collaboration with the NASA Earth Observatory (https://earthobservatory.nasa.gov/).

Story adapted from Image of the Day post by Kasha Patel: https://earthobservatory.nasa.gov/images/92090/the-floating-islands-of-india

  • Image of Floating Islands in Loktak Lake from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on the Terra satellite. 
  • Ground-level Image of Phumdis, by Sharada Prasad CS
  • Written by Katherine Porter
  • Designed by Dani Player 
  • Music from Yesh Music (ASCAP)

Collage of distinct satellite images of natural phenomena.
Text, where on earth? Satellite image, a body of water speckled with green dots.
Text, what are the round green spots in this satellite image? A, coral reefs off the coast of Fiji, B, floating islands on a lake in India, C, algae blooms in a reservoir in Florida, D, pods of whales off the coast of Japan.
B is highlighted, floating islands on a lake in India. Labels appear on map.
Text, Floating Islands in Loktak Lake, India. Loktak Lake is the largest freshwater lake in northeast India.
It is an important source of water and food for the region.
Unique floating islands called phumdis are scattered throughout the lake.
The islands are made of soil, plants, and decaying organic matter, and they extend far beneath the surface of the water.
During the dry season, the water levels in the lake drop.
This allows the roots of the plants on the island to reach the soil below and gather nutrients.
The islands have a spongy springy surface that can support a fair amount of weight. Image, a structure rests on one of the islands.
Text, some of the islands are large enough to support buildings and other features, including a school and the world's only floating national park.
The map recedes until we have the whole Earth before us.
Text, where on earth?