title: Removal of fast flowing nitrogen from marshes restored in sandy soils.
abstract: Groundwater flow rates and nitrate removal capacity from an introduced solution were examined for five marsh restoration designs and unvegetated plots shortly after planting and 1 year post-planting. The restoration site was a sandy beach with a wave-dampening fence 10 m offshore. Simulated groundwater flow into the marsh was introduced at a rate to mimic intense rainfall events. Restoration designs varied in initial planting density and corresponded to 25%, 50%, 75% and 100% of the plot area planted. In general, groundwater flow was slower with increasing planting density and decreased from year 0 to year 1 across all treatments. Nevertheless, removal of nitrate from the introduced solution was similar and low for all restoration designs (3-7%) and similar to the unvegetated plots. We suggest that the low NO3(-) removal was due to sandy sediments allowing rapid flow of groundwater through the marsh rhizosphere, thereby decreasing the contact time of the NO3(-) with the marsh biota. Our findings demonstrate that knowledge of the groundwater flow regime for restoration projects is essential when nutrient filtration is a target goal of the project.
authors.affiliation: Dauphin Island Sea Lab, Dauphin Island, Alabama, United States of America; Marine Sciences, University of South Alabama, Mobile, Alabama, United States of America.
authors.forename: Eric L
authors.initials: EL
authors.lastname: Sparks
authors.affiliation: Dauphin Island Sea Lab, Dauphin Island, Alabama, United States of America; Marine Sciences, University of South Alabama, Mobile, Alabama, United States of America.
authors.forename: Just
authors.initials: J
authors.lastname: Cebrian
authors.affiliation: Dauphin Island Sea Lab, Dauphin Island, Alabama, United States of America.
authors.forename: Sara M
authors.initials: SM
authors.lastname: Smith
mesh_terms: D019015:Geologic Sediments / Q000737:chemistry; D060587:Groundwater / Q000737:chemistry*; D009584:Nitrogen / Q000032:analysis*; D012822:Silicon Dioxide / Q000032:analysis; D012987:Soil / Q000737:chemistry*; D053833:Wetlands
chemical_list: D012987:Soil; D012822:Silicon Dioxide; D009584:Nitrogen