Overfishing. Many authors have cited overfishing as the cause of the cod stock collapse. In the case of the Newfoundland cod, there were three distinct groups involved in harvesting the resource: local inshore fishermen, Canadian draggers and trawlers, and deep-sea foreign fishing vessels.
Early bacteria and plants released carbon dioxide as well as oxygen when they performed photosynthesis. because bacteria could have been aerobic back then and released carbon dioxide for the plants to use in photosynthesis.