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Perhaps the most profound geobiological event is the introduction of oxygen into the atmosphere by photosynthetic bacteria. This oxygenation of Earth's primoidial atmosphere (the so-called oxygen catastrophe) resulted in the precipitation of banded-iron rock formations.
A subsequent major change was the establishment of terrestrial plant life, which affected continental erosion and changed the types of rivers observed, allowing channelization of what were previously predominantly braided rivers.
More subtle geobiological events include the role of termites in overturning sediments, coral reefs in depositing calcium carbonate and breaking waves, sponges in absorbing dissolved marine silica, the role of dinosaurs in breaching river levees and promoting flooding, and the role of large mammal dung in distributing nutrients.
Another related area of research is astrobiology, an interdisciplinary field that uses a combination of geobiological and planetary science data to establish a context for the search for life on other planets.
One example of geobiological research in a modern context is the study of bacteria that "breathe" metals such as manganese and uranium. These organisms use metals as terminal electron acceptors in the same way that animals use oxygen. These processes hold promise as tools for environmental bioremediation.