Janet Kenny, age 12, of Redlands, California, for her question:
How did oil eat under the oceans?
Nobody has proved exactly how the earth creates her underground reservoirs of oily petroleum. But most geologists are sure that the recipe starts in the seas and that the process continues underwater through millions of years. If this theory is correct, then it seems logical to look for deposits of petroleum under the oceans.
Researchers have done many experiments trying to learn just how oil is formed by nature. They know that certain bacteria can convert masses of organic marine life into an oily substance somewhat similar to the stuff we call petroleum, or crude oil. The marine life is composed of the teeming one celled plants and animals present in surface waters of the seas. So far, we have not exactly duplicated nature's recipe, which is why the true scientists refuse to state that they know the secret. Maybe there is a mystery ingredient in the recipe. We do not know whether nature is still creating more oil or whether an unidentified bacterium or some other ingredient has departed from the earth.
However, there is lots of evidence that the petroleum recipe always began in the seas, often in shallow waters that slopped over the land areas hundreds of millions of years in the past. The sunny ancient waters teemed with single celled plants and animals, just as they do today. They converted chemicals around them into complex substances called hydrocarbons. Countless zillions of these cells sifted down to the ocean floors. They filtered through the sand and silty mud and carpeted the seabeds with immense deposits of oozy slime.
These deposits were later covered with layers of sand and silt and 11my little seashells. Certain types of bacteria were also present, busily digesting the organic marine material. The bacteria process, plus heat and pressure from the earth, began the petroleum recipe or so we suspect. Through the ages, the mixture was buried deeper and deeper under newer sediments. Sometimes these upper layers were compacted into dense rocks that sealed down the petroleum. Then, much later, large areas of the seas retreated, leaving their ancient beds high and dry. In some places their buried reservoirs of petroleum now belonged to the land. But not all of them. Many were still buried under coastal waters and perhaps farther out to sea.
When searching for likely oil deposits on land, geologists always select regions that once were flooded by ancient seas. Sometimes these great oil fields extend through thousands of miles. It seemed logical to suspect that more oily reservoirs were still under the seas and in recent years ways were found to tap them. At present, about one¬ fifteenth of our petroleum is drilled up from beneath coastal waters. Four of our largest oil fields are in the coastal states of California and Alaska, Texas and Louisiana. And these buried reservoirs extend out under the sea where offshore drilling is possible.
Crude oil as it comes from the earth is flammable and very, very tacky stuff. Offshore drilling is especially tricky because a slight error or accident can release the tapped oil into the water. Tides sweep it towards the shores where it befouls the beaches. In the water, the oily pollution suffocates whole populations of fish and other sea dwellers and brings final tragedy to countless sea going birds. Our cars need gasoline from petroleum. But this heart breaking pollution makes some of us decide to walk to the store or buy a bike.