97 Life in a Biosphere

Drawings of human colonies on other planets often picture the entire community under a glass or plastic bubble. The bubble is intended to create an atmosphere with adequate oxygen and other essential elements. But similar bubblelike structures have also been constructed on earth. One of the most famous, and controversial, is a site in the Arizona desert.

Biosphere 2, as it is called, was built not far from Tucson in 1984 and is now run by Columbia University. This huge (7,200,000-cubic-foot) glass and steel construction contains several separate ecosystems, including a desert, a rain forest, and a 900,000-gallon “ocean.” The climactic conditions—humidity, temperature, air quality—are regulated by sensors and can be adjusted as needed or desired. For example, a rainstorm can be created to increase the humidity. These adjustable features of Biosphere 2 make it an ideal location to perform experiments to help determine the effects of such climactic changes as global warming.

The current conditions at Biosphere 2 are vastly different from those in 1993, when eight people who had moved into the environment with great fanfare two years earlier moved out in failure. Though promising to be self-sufficient, these “colonists” had so much trouble regulating the environment that they reportedly had food smuggled in to them. Oxygen levels became dangerously low; most plants and animals died. In taking over the unsuccessful site, Columbia hopes to erase its notorious past by focusing on small research projects that gradually answer some of Biosphere 1’s—that is, Earth’s—most basic environmental questions.

97 生物圈中的生活

关于其他星球上人类殖民地的绘画，通常会描绘整个社区处于玻璃或塑料泡泡之下。这个泡泡的目的是创造一个含有充足氧气和其他基本元素的 atmosphere。但类似的泡泡状结构也在地球上建造过。其中最著名、也最具争议的一个，位于亚利桑那州的沙漠中。

这个被称为“生物圈2号”的设施，于1984年在图森附近建成，现在由哥伦比亚大学运营。这个巨大的（720万立方英尺）玻璃和钢铁建筑包含几个独立的生态系统，包括沙漠、雨林和一个90万加仑的“海洋”。气候条件——湿度、温度、空气质量——由传感器调节，可以根据需要或意愿进行调整。例如，可以制造一场暴雨来增加湿度。生物圈2号的这些可调节特性，使其成为进行实验的理想场所，有助于确定全球变暖等气候变化的影响。

生物圈2号现在的状况与1993年大不相同：1993年，两年前大张旗鼓搬进这个环境的八个人，以失败告终搬了出去。尽管这些“殖民者”承诺要自给自足，但他们在调节环境方面遇到了极大的困难，据报道他们不得不让人偷偷送食物进来。氧气水平变得极低，大多数动植物死亡。哥伦比亚大学接管这个失败的设施后，希望通过专注于小型研究项目来抹去其臭名昭著的过去，这些项目将逐步回答生物圈1号（即地球）最基本的一些环境问题。