<P> The Bohr effect is a physiological phenomenon first described in 1904 by the Danish physiologist Christian Bohr: hemoglobin's oxygen binding affinity (see oxygen--haemoglobin dissociation curve) is inversely related both to acidity and to the concentration of carbon dioxide . That is, the Bohr effect refers to the shift in the oxygen dissociation curve caused by changes in the concentration of carbon dioxide or the pH of the environment . Since carbon dioxide reacts with water to form carbonic acid, an increase in CO results in a decrease in blood pH, resulting in hemoglobin proteins releasing their load of oxygen . Conversely, a decrease in carbon dioxide provokes an increase in pH, which results in hemoglobin picking up more oxygen . </P> <P> In the early 1900s, Christian Bohr was a professor at the University of Copenhagen in Denmark, already well known for his work in the field of respiratory physiology . He had spent the last two decades studying the solubility of oxygen, carbon dioxide, and other gases in various liquids, and had conducted extensive research on haemoglobin and its affinity for oxygen . In 1903, he began working closely with Karl Hasselbalch and August Krogh, two of his associates at the university, in an attempt to experimentally replicate the work of Gustav von Hüfner, using whole blood instead of haemoglobin solution . Hüfner had suggested that the oxygen - haemoglobin binding curve was hyperbolic in shape, but after extensive experimentation, the Copenhagen group determined that the curve was in fact sigmoidal . Furthermore, in the process of plotting out numerous dissociation curves, it soon became apparent that high partial pressures of carbon dioxide caused the curves to shift to the right . Further experimentation while varying the CO concentration quickly provided conclusive evidence, confirming the existence of what would soon become known as the Bohr effect . </P>

As co concentrations increase what happens to oxygen binding to hemoglobin