The science of organic Geochemistry bridges the gap between living and fossil organisms. It is concerned with the processes by which organic material changes after death, during sediment burial, diagenesis and maturation, to produce gas, liquid petroleum and coal. It is equally concerned with the way in which organic matter of geological origin enters the biosphere and interacts with living organisms. Applications of organic geochemistry to the petroleum industry include exploration (developing the ability to predict the occurrence of petroleum within a sedimentary basin) and production (predicting the response of reservoir rocks to interaction with organic-rich pore fluids) as well as in fingerprinting oil spills.