Physiological Mechanisms of Estuarine Sediment Oxidation by Spartina Cordgrasses

EPA Grant Number: R829406
Title: Physiological Mechanisms of Estuarine Sediment Oxidation by Spartina Cordgrasses
Investigators: Lee, Raymond W.
Institution: Washington State University
EPA Project Officer: Lasat, Mitch
Project Period: November 1, 2001 through October 31, 2004
Project Amount: $110,307
RFA: Phytoremediation (2001) RFA Text |  Recipients Lists
Research Category: Hazardous Waste/Remediation , Land and Waste Management


Cordgrasses of the genus Spartina will be investigated for their potential use as a phytoremediation tool in marine and estuarine sediments. Spartina grasses are adapted to saline, waterlogged sediments and exhibit vigorous growth, forming dense monospecific stands in a variety of intertidal environments. The capability of these plants to transport oxygen from the atmosphere to the belowground rhizosphere has the potential to enhance microbial degradation of organic pollutants, which can be limited by oxygen availability in anoxic waterlogged soils. The specific objectives are as follows: (1) determine rates of oxygen transport and release by Spartina grasses; (2) identify species and strains of Spartina that have enhanced oxygen release capabilities; (3) determine the mechanisms that facilitate oxygen transport, and how transport is induced by environmental and hormonal signals. These studies will assist in recovery of estuarine environments affected by pollution.


A newly designed automated flow-through respirometry system will be used to quantify rates of oxygen transport to belowground tissues and release into the medium. This ability in different species of Spartina as well as Spartina collected from different locales and environments will be tested for. The role of internal gas spaces (aerenchyma) will investigated by quantifying aerenchyma volume by light microscopy and digitized image analysis. Experiments will be conducted testing the effects of environmental conditions (flooding, anoxia) and plant hormones (ethylene) on the development of oxygen transport capabilities and aerenchyma.

Expected Results:

Maximizing release of oxygen into sediments is a means of manipulating plant-microorganism interactions in a manner that can potentially enhance pollutant degradation. Species and strains of Spartina that exhibit high rates of oxygen transport will be identified, as well as the environmental and hormonal signals that are required for maximum effectiveness. These studies will help facilitate the use of Spartina in phytoremediation of organic pollutants in marine and estuarine sediments.

Publications and Presentations:

Publications have been submitted on this project: View all 18 publications for this project

Journal Articles:

Journal Articles have been submitted on this project: View all 2 journal articles for this project

Supplemental Keywords:

aquatic, marine science, biology., Scientific Discipline, Waste, Water, Environmental Chemistry, Contaminated Sediments, Remediation, Chemistry, Environmental Microbiology, Microbiology, Bioremediation, Biology, aquatic ecosystem, plant-based remediation, degradation, degradation of organic pollutants, organic pollutants, microbial degradation, biodegradation, estuarine sediments, bioremediation of soils, aquatic ecosystems, phytoremediation, plant-microbe system

Progress and Final Reports:

  • 2002 Progress Report
  • 2003
  • Final Report