Grantee Research Project Results
Interaction Between Grazing and Nutrients as Controls of Macrophyte Biomass and Community Structure in Shallow Temperate Estuaries
EPA Grant Number: U915335Title: Interaction Between Grazing and Nutrients as Controls of Macrophyte Biomass and Community Structure in Shallow Temperate Estuaries
Investigators: Hauxwell, Jennifer A.
Institution: Boston University
EPA Project Officer: Packard, Benjamin H
Project Period: September 1, 1998 through January 1, 1999
Project Amount: $61,632
RFA: STAR Graduate Fellowships (1998) RFA Text | Recipients Lists
Research Category: Fellowship - Ecology , Ecological Indicators/Assessment/Restoration , Academic Fellowships
Objective:
The objective of this research project is to determine how anthropogenic nitrogen inputs, grazing by benthic invertebrates, and competitive interactions between macroalgae and seagrasses influence macrophyte biomass and community structure (seagrass- or macroalgal-dominated) in shallow temperate estuaries.
Approach:
I will collect experimental and descriptive field data from different estuaries of Waquoit Bay, MA, that are exposed to different nitrogen loads. I will conduct monthly benthic surveys for 1 year to assess macroalgal and eelgrass biomass and areal coverage, and invertebrate grazer abundances. Additional field data will include annual eelgrass growth rates and shoot density to allow an estimation of production. I will model grazer impact on macroalgal biomass based on survey data, field grazing rates by abundant herbivores on their algal foods, and in situ macroalgal growth measurements. To examine the effect of grazers and nitrogen-loading rates on epiphytes of eelgrass, I will determine: (1) the epiphyte load of eelgrass in estuaries exposed to differing nitrogen loads; (2) the effect of epiphytes on eelgrass growth in these estuaries; and (3) the effect of grazers on epiphyte biomass. I will conduct field-shading experiments in which I exclude macroalgae from plots of eelgrass or include macroalgae at differing canopy heights (corresponding to different nitrogen loads), and measure the impact on eelgrass density and growth to examine the interaction between macroalgal canopies and eelgrass production. The results will allow a synthesis of control processes that govern how macrophytes and grazers interact in shallow water coastal ecosystems, how controls seasonally vary, and how the grazer/macrophyte system is coupled to external anthropogenic inputs of nutrients from adjoining terrestrial ecosystems.
Supplemental Keywords:
fellowship, macrophyte biomass, anthropogenic nitrogen inputs, benthic invertebrates, macroalgae., RFA, Ecosystem Protection/Environmental Exposure & Risk, Scientific Discipline, Geographic Area, Aquatic Ecosystem, Aquatic Ecosystems & Estuarine Research, State, Ecology and Ecosystems, aquatic plants, benthic invertebrate patterns, macroalgal blooms, benthic marine invertibrates, macrophyte biomass, anthropogenic impact, estuarine research, estuarine waters, nitrogen cycling, aquatic ecosystems, seagrassProgress and Final Reports:
The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.