Radial oxygen loss in wetland plants: Potential impacts on remediation of contaminated sediments

Remediation of sediments contaminated with persistent organic compounds such as polycyclic aromatic hydrocarbons has been problematic due to the lack of oxygen in saturated sediments. Certain wetland plants have the potential to create aerobic conditions in the anoxic sediments through radial oxygen loss into the rhizosphere. The objective of the current study was to utilize several methods of measuring radial oxygen loss to identify wetland species with relatively high rates of oxygen loss into the rhizosphere. The results show clearly that there are significant differences between plant species in terms of radial oxygen loss. Rates in the current study ranged from 0 cm2 (Lobelia cardinalis) oxygenated to 56 cm2 (Sagittaria latifolia). In addition, the three methods of measuring radial oxygen loss showed consistency in the high radial oxygen loss species, but we found that the methylene blue agar method was more sensitive in detecting differences between species and also enabled visualization of where the radial oxygen loss was taking place across the root system.