Effects of moderate eutrophication on saltmarsh food webs

Project Type: 
Core Research Project
Project Leader: 
Research Partners: 
David S. Johnson (MBL)
Project Fellows: 
Status: 
Ongoing
Science Themes: 

We examine the impacts of moderate nutrient enrichment on the production mummichog, Fundulus heteroclitus, as part of a 10-year whole ecosystem experiment in a Plum Island Sound saltmarsh. In the initial stages of nutrient enrichment we observed a classic bottom up stimulation response in fish production. However, after the first six years fish production declined rapidly. The mechanism for the decline is not known but we hypothesize indirect interactions with other saltmarsh consumers may play an important role, as well a habitat alteration. Our results demonstrate that long-term nutrient enrichment can have complex impacts on the production of saltmarsh fish that are not predictable by classic bottom up/ top down control theory. Our findings suggest that eutrophication and climate change induced sea level rise will have synergistic negative effects on the production of saltmarsh fish primarily through habitat alteration and loss. Information from this project is being used to set standards for nutrient levels in coastal marshes.

Publications: 

 

Presentations: 
  • Chronic Nutrient Press Differentially Alters Salt Marsh Ecosystem Functions. L. Deegan. Joint Aquatic Science Meeting, Portalnd, Oregon. May 19-26, 2014.
  • MBL Undergraduate Research Symposium. Aug 20, 2014. The effect of diet on fatty acid content and assimilation efficiencies in Fundulus heteroclitus. Alison Hall (Carelton College Biology Department and Woods Hole Marine Biological Laboratory Ecosystems Center), James Nelson (Woods Hole Marine Biological Laboratory Ecosystems Center) and Amanda Spivak (Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institute)
Other: 
  • Undergraduate Honors Thesis: Bethany Williams, Florida State University: Sea-level rise effects on the coffee-bean snail, Melampus bidentatus