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. In 2016, we conducted a 15N tracer experiment to test the concept of bottom up vs creek edge and marsh platform control of mummichog production and have been processing and analyzing samples.
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. We examine the impacts of moderate nutrient enrichment on the production mummichog, Fundulus heteroclitus, as part of a 9-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.
- Johnson, D.S. and M. I. Short. 2013. Chronic nutrient enrichment increases the density and biomass of the eastern mudsnail, Nassarius obsoletus. Estuaries and Coasts 36: 28-35
- Pascal, P-Y, J.W. Fleeger, H.T.S. Boshker, H. Mitwally, and D.S. Johnson. 2013. Chronic nutrient-enrichment influence on mudflat food web in a New England (USA) estuary. Marine Ecology Progress Series. 474:27-41
- Johnson, D.S. 2014. Weeds making waves. Essay. Science 344:255
- Johnson, D. S., Warren, R. S., Deegan, L. A. and Mozdzer, T. J. (2016), Saltmarsh plant responses to eutrophication. Ecol Appl, 26: 2649–2661. doi:10.1002/eap.1402
- Crosby, S. C., D. Sax, M. E. Palmer, H. S. Booth, L. A. Deegan, M. D. Bertness, H. M. Leslie. 2016. Salt marsh persistence is threatened by predicted sea-level rise. Estuarine, Coastal and Shelf Science 181: 93-99
- Kearns G, P., J. H. Angell G, E. Howard G, L. A. Deegan, R. H. Stanley, and J. L. Bowen. 2016. Nutrient enrichment induces dormancy and decreases diversity of active bacteria. Nature Communications.
- 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)
- Undergraduate Honors Thesis: Bethany Williams, Florida State University: Sea-level rise effects on the coffee-bean snail, Melampus bidentatus
- James A. Nelson, David S. Johnson, Linda A. Deegan, Amanda C. Spivak, Nathalie R. Moore. Geomorphology modifies bottom-up control on food webs . Ecological Applications. In Revision.