A lot of discussion has been centering on Roxanne Conlin's historic bid to become Iowa's first female elected to the U.S. Senate. Iowa has never elected a woman to Congress and we share that distinction with just one other state – Mississippi.
Yet, this isn't the only connection between Iowa and our friends to the south in Mississippi. The other is water, and the issue that is beginning to get more attention as people focus on the Gulf oil spill is hypoxia.
Hypoxia or oxygen depletion is a phenomenon that occurs in aquatic environments as dissolved oxygen (DO; molecular oxygen dissolved in the water) becomes reduced in concentration to a point detrimental to aquatic organisms living in the system. Dissolved oxygen is typically expressed as a percentage of the oxygen that would dissolve in the water at the prevailing temperature and salinity (both of which affect the solubility of oxygen in water; see oxygen saturation and underwater). An aquatic system lacking dissolved oxygen (0% saturation) is termed anaerobic, reducing, or anoxic; a system with low concentration—in the range between 1 and 30% saturation—is called hypoxic or dysoxic. Most fish cannot live below 30% saturation. A “healthy” aquatic environment should seldom experience less than 80%. The exaerobic zone is found at the boundary of anoxic and hypoxic zones