Vaguely resembling a giant sea turtle, Barro Colorado Island is a heavily forested patch of land rising up out of the waters of Gatun Lake, situated at the northern end of the Panama Canal. The island is the focus of the JASON Project’s Expedition XV (“Rainforests at the Crossroads”), in which students, teachers, and scientists will conduct a detailed examination of the rainforest ecosystem. The expedition will be televised to the international network of JASON schools, and an interactive lesson featuring the use of NASA satellite remote sensing data is now available on the Earth Observatory.
The true-color scene above was acquired on March 29, 2002, by the DigitalGlobe Corporation’s QuickBird satellite. At better than 1-meter resolution, the satellite reveals Barro Colorado Island in stunning detail. Several small cumulus clouds float silently over the western portion of the island, casting shadows on the surface. A ship can be seen cruising past the island’s northeastern shore. The red roofs of the Smithsonian Tropical Research Institute can be seen peeking through the dark green canopy just inland from the bay to the south of the ship’s position. Barro Colorado Island has been managed since 1924 by the Smithsonian Institute and is one of the premier sites in the world for study of tropical forests and the plants and animals that inhabit them.
At this resolution, one can easily spot the many Guayacan trees blooming all over the island. The trees’ canopies fill up with bright yellow blossoms, appearing as bright yellow splotches in this scene. According to tropical ecologists, the first showers of the rainy season cause the Guayacans to flower.
Barro Colorado Island was not formed by natural events, such as volcanic activity or tectonic plate movement. Instead, human activities are responsible for the island’s creation. Back in the early 1900s, the area of Panama now known as Barro Colorado Island was a big hill, called West Hill, located in the Chagres River Valley. A lush green canopy of tropical rainforest covered much of the valley, but people also lived in the valley and converted some areas into farmland. In fact, some of the towns and villages in the valley were hundreds of years old!
In 1914, engineers who were working on the Panama Canal constructed a dam to block the Chagres River’s outflow. The dam changed the way the river flowed and caused water to rise in the Chagres River Valley. New lakes, like Gatun Lake, were created in the process and entire towns, forested areas, and farmlands were flooded. As the water rose, the lower portions of West Hill were also covered by water and the top part of the hill became an island—Barro Colorado Island.
On September 25, 2002, astronauts aboard the International Space Station viewed Easter Island, one of the most remote locations on Earth. Easter Island is more than 2000 miles from the closest populations on Tahiti and Chile—even more remote than astronauts orbiting at 210 nautical miles above the Earth. Archaeologists believe the island was discovered and colonized by Polynesians at about 400 AD. Subsequently, a unique culture developed. The human population grew to levels that could not be sustained by the island. A civil war resulted, and the island’s deforestation and ecosystem collapse was nearly complete.
Named Isla de Aves in Spanish, (meaning “Island of the Birds”) Aves Island lies west of the Lesser Antilles in the Caribbean. It provides a nesting site to green sea turtles (Chelonia mydas) and, of course, birds. Because the abundant bird droppings, known as guano, could be used in fertilizer and gunpowder, guano miners worked on the island until they depleted the supply. Since its discovery by Europeans, likely in the late 16th century, Aves Island was subsequently claimed by several European nations. The island is currently claimed by Venezuela, although disputes about ownership of the island, and the surrounding exclusive economic zone in the Caribbean, continue today.