Oxygen Transport through Selected Aquatic Macrophytes

Abstract

The extent of O2 transport from aerial plant tissue into the root zone was evaluated for several floating and emergent aquatic macrophytes that have characteristics favorable for wastewater treatment. The highest O2 transport rates from aerial tissue into the root zone were associated with plants having a small root mass. As root mass increased, the rate of O2 transport decreased for aquatic macrophytes evaluated. Pennywort (Hydrocotyle umbellata L.) had the highest O2 transport rate of all aquatic macrophytes with an overall rate of 3.49 g O2 kg−1 dry root mass h−1. Pickerelweed (Pontederia cordata L.) had the highest O2 transport capacity of emergent plants with a rate of 1.54 g O2 kg−1 h−1. Waterhyacinth [Eichhornia crassipes (Mart.) Sollms], an important floating aquatic plant in wastewater treatment, had a transport rate of 1.24 g O2 kg−1 h−1. Nitrification in a waterhyacinth‐based water treatment system due to O2 transport was calculated to vary from 6 to 22 kg ha−1 d−1.

The Function of Marine Critical Transition Zones and the Importance of Sediment Biodiversity

“…Sediment-dwelling benthic animals in turn can increase the percolation of water and oxygen levels through solute pumping or by the bioturbation associated with deposit-feeding or burrowing (Aller 1982;Rhoads and Boyer 1982). Vegetation has a similar effect by transporting oxygen to roots, where it enters the rhizosphere (Armstrong 1964; Moorhead and Reddy 1988). In addition, vegetation moderates rates of water flow, affecting animal movement, nutrient dynamics, and particle deposition (Jumars and Nowell 1984).…”

Nutrient removal by floating aquatic macrophytes cultured in anaerobically digested flushed dairy manure wastewater

“…A study conducted by Moorhead and Reddy (1988) to evaluate oxygen transport into the root zone for several floating and emergent aquatic macrophytes showed that the highest transport rates were associated with plants having a small root mass. As root mass increased, the rate of oxygen transport decreased for the plants evaluated, suggesting that older plants and plants with extensive rooting systems probably consume more of the transported oxygen due to higher respiration rates.…”

Floating Aquatic Macrophytes Decrease the Methane Concentration in the Water Column of a Tropical Coastal Lagoon: Implications for Methane Oxidation and Emission

“…The concomitant higher O 2 uptake and the decrease in pH in these treatments also indicate the heterotrophic activity with CO 2 formation. Previous studies showed the capability of free-floating aquatic macrophytes in transporting oxygen from the foliage to the rhizosphere 45,46 . The roots within the water column act as a living substrate for the growth of attached aerobic bacteria, which consume the oxygen to decompose dissolved organic compounds 47 .…”