You are here:
Response of Spartina Alterniflora to Sea Level Rise, Changing Precipitation Patterns, and Eutrophication
Citation:
WIGAND, C., Alana Hanson, Roxannel Johnson, A. Oczkowski, E. Watson, E. Davey, E. Markham, AND S. Corman. Response of Spartina Alterniflora to Sea Level Rise, Changing Precipitation Patterns, and Eutrophication. Presented at New England Estuarine Research Society (NEERS) Spring Meeting, Portland, ME, April 11 - 14, 2013.
Impact/Purpose:
The presentation supports SHC 3.3.1 project: Informing Sustainable Decisions about Nitrogen, led by Jana Compton (WED). The greenhouse experiment described is part of a task (SHC 3.3.1.11) in Compton’s project. The results suggest that multiple stressor effects of sea level rise, changing precipitation, and eutrophication will result in alterations of the morphology of the stems, roots, and rhizomes of Spartina alterniflora, which will affect decomposition rates, organic matter content of the peat, and susceptibility of soils to erosion.
Description:
Sea level rise, precipitation, and eutrophication (3 X 3 X 2 factorial design) were simulated in tidal mesocosms in the US EPA Narragansett greenhouse. Each precipitation treatment (storm, drought, ambient rain) was represented in one of two tanks (control, fertilized). The control tanks received ambient seawater and the fertilized tanks an input of nutrients to simulate a eutrophic system (32 µM nitrate, 2 µM phosphate). In each tank there were 12 Spartina alterniflora pots: four each at heights of 30, 45, or 60 cm. The different pot heights provided for varying duration and frequency of flooding and simulated varying marsh landscape elevations. After 4 months there were no fertilization effects on the total above- or below-ground biomass, although morphological differences were apparent. The stems grown under fertilized conditions were more abundant and narrower than unfertilized plants. The control pots had taller plants, which were associated with a significantly greater abundance of coarse roots and rhizomes, while the fertilized pots had the greatest densities of short stems associated with significantly more fine roots. There were precipitation and sea level rise effects, with the ambient rain having significantly greater plant biomass than drought or storm treatments, and the pots with the greatest duration of flooding (i.e., 30 cm pots) having the lowest plant biomass. Decomposition rates were significantly elevated in the fertilized treatments, with the greatest rates at the highest elevations (i.e., 60 cm pots). Multiple stressor effects on the structure of the stems, roots, and rhizomes will affect decomposition rates, organic matter content of the peat, and susceptibility of soils to erosion.