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Microbial Indexing of Saltmarsh Health and Recovery: Development of a Health/Productivity Scale


PIs: Marc Frischer (Skidaway Institute of Oceanography, Savannah, GA), Jeffrey King (US Army Corps/Adjunct SkIO), Carla Curran (Savannah State Univ., GA), and Dionne Hoskins (Savannah State Univ., GA)

Support: Georgia Coastal Management Program (through a Coastal Incentive Grant)

Timeframe: 2004 - 2006

Project Objective:

To develop a statistics-based predictive tool informed by microbiological and geochemical data to classify the health and productivity of Spartina alterniflora dominated saltmarsh environments.

Progress:

Efforts focus on four marsh sites representing the range of marsh health endpoints, Oatland Island (pristine), Isle of Hope (recovered die-back area), Delegal Marina (recovering die-back area), and Elba Island (constructed saltmarsh).

Laboratory analyses of 8 independent samples from 4 sites during the spring and summer included:

  • Physical Parameters: temperature, salinity, sediment wet weight, sediment dry weight, sediment porosity
  •  Porewater Geochemistry: alkalinity, chloride, NH4, NO3/NO2, PO4, SiO4, Fe2+, SO4, H2S, DOC, TOC solid
  •  Microbial Activity: total sediment respiration (CO2 and CH4), sulfate reduction rate
  •  Microbial Community Structure: total eubacterial community structure, sulfate reducing bacteria community structure
  •  Marsh Parameters: S. alterniflora height, live stem density, dead stem density, snails, mussels, crab burrows

Initial quantitative multivariate regression and qualitative principle component analysis models were developed.

Findings:

        Results of these models indicate that the 4 variables (porewater concentration of NH4, NO3/NO2, PO4, and the ratio of total bacterial respiration rates to sulfate reduction rates) can be used to evaluate marsh health status. Furthermore, these models indicate that seasonal difference in plant growth during the spring/summer growing season provides a good indicator of marsh health. Development of a quantitative discriminant factor analysis model is ongoing.

Publications and Presentations:

Fogleman, T. and M.C. Curran. 2006. Save our salt marshes! Using educational brochures to increase student awareness of salt marsh ecology. Current: The Journal of Marine Education 22:23-25.


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This page was updated September 1, 2009