One lobe of Lake Bonney provides an example of chemistry and bacteria in harmony, while the other provides an example of what can go wrong. Nitrous oxide is the most alarming of the east lobe's wealth of nitrogen-based chemicals. A bucket of water from the east lobe contains 5,000 times more nitrous oxide gas than a bucket of ocean water. The lake holds so much nitrous oxide and other gases that the water bubbles when Ward and her colleagues haul it to the surface. By analyzing chemicals deposited deep in Antarctic glaciers, scientists have found that the atmosphere contains more nitrous oxide today than it has for the last 45,000 years.
Nitrous oxide is a greenhouse gas, meaning it contributes to global warming.
Though carbon dioxide is at least 50 times more abundant, nitrous oxide packs more of a warming punch in each molecule. Commonly known as laughing gas, nitrous oxide does not just billow from dentists' offices. Industrial sources of nitrous oxide include nylon manufacturing, fossil-fuel burning, and nitrogen fertilizing. When all these sources are added together, they still do not completely account for the abundance of nitrous oxide. When asked to join an Antarctic expedition in 1991, Ward agreed to go only after being prodded by her graduate student, Mary Voytek.