Biomarkers of health in Spartina alterniflora: comparison of native, restored, and impacted coastal marshes in the Galveston Bay, Texas system
The highest priority stated in the 1995 Galveston Bay Plan is to protect and restore coastal wetland habitats. In fact, over the past seven years, several million dollars have been spent creating and/or restoring over 20 Spartina alterniflora marshes in the Galveston Bay estuary system. Although S. alterniflora in these created/restored marshes have been monitored for density, area expansion and use by nekton, the fundamental health of these salt marsh grass communities, and how they tolerate or adapt to environmental and pollution stresses, is still largely unknown. In this project we evaluated nine biomarkers of health in S. alterniflora from six sites representing unimpacted native, restored/created, and pollutant-impacted coastal salt marshes in Galveston Bay. Productivity (e.g., density, growth, biomass and chlorophyll a and b), physiological health (e.g., peroxidase, glutathione reductase and catalase activities, lipid peroxidation, and metallothionein) and toxicant accumulation (e.g., heavy metals) were evaluated in replicate samples collected from each site. Specific measures of productivity were significantly higher in the native and created marshes compared to the impacted and degraded sites. Results for the five physiological biomarkers varied significantly among the sites and appear to be dependent on a complex combination of environmental, physical and genetic factors, a number of which are related to whether the Spartina marshes are naturally established or restored/created.