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.