Anthropogenic Nutrient Input and Its Influence on Plant Competitive Outcomes: Implications for Habitat Degradation and Community Shifts

EPA Grant Number: FP917484
Title: Anthropogenic Nutrient Input and Its Influence on Plant Competitive Outcomes: Implications for Habitat Degradation and Community Shifts
Investigators: Miller, Molly Mintz
Institution: University of South Alabama
EPA Project Officer: Lee, Sonja
Project Period: August 20, 2012 through August 19, 2015
Project Amount: $126,000
RFA: STAR Graduate Fellowships (2012) RFA Text |  Recipients Lists
Research Category: Fellowship - Marine Sciences , Academic Fellowships


The objectives of this study are to: (1) determine what, if any, positive influences non-native aquatic plants have on the ecosystems they invade; (2) integrate nitrogen and carbon metabolism, and identify molecular markers that respond to nutrient availability as a means of understanding the underlying mechanisms of resource competition between native and non-native plants; and (3) determine what influence the changing atmospheric CO2 concentration will have on nitrogen acquisition and assimilation in key aquatic plant species.


An integrated approach toward addressing the impact of Non-Point Source (NPS) nutrient pollution on native and non-native aquatic plant performance and competitive ability with a specific emphasis on nitrogen will be taken. Traditional biochemical (enzyme activity) and physiological (Chl-a fluorescence and oxygen evolution) as well as quantitative assays of gene expression (qPCR) and changes in global protein abundance (differential proteomic analysis) will be conducted to investigate the plant response to nutrient availability. Coupled with biochemical and physiological data, these techniques will provide biologically based mechanistic data, allowing for the integration of relevant sub-organismal processes into organismal performance and infer fitness in the field.

Expected Results:

By taking a multifactorial approach, the study will document complex aquatic plant responses to NPS nutrient contamination, providing fundamental insight into the broader impacts of environmental degradation, its impacts on plant function, and implications for ecosystem services (e.g., nutrient remediation). Finally, armed with a better understanding of how plants physiologically respond to resource fluctuations, simple models will be developed to guide future field project design, allowing appropriate testing of inferences about the ability of plants to remediate nutrient pollution, interspecific plant interactions and resource competition, and the roles these processes play in determining ecosystem health in nature.

Potential to Further Environmental/Human Health Protection
Poor water quality and its obvious impacts on ecosystem structure and function constitute a major environmental and potential human health problem. Although declines and/or compositional shifts in aquatic vegetation have been linked to increases in water column nutrient concentrations, it is unclear how such changes affect the overall capacity of aquatic plant communities to remove toxic compounds (the most common form of which is nitrate) from near-shore waters. Moreover, as global climate changes and atmospheric CO2 levels rise, taxonomic differences in plant physiological responses will necessarily influence nutrient uptake and assimilatory processes, resource competition and overall ecosystem health.

Supplemental Keywords:

invasive plants, water quality, nonpoint source pollution

Progress and Final Reports:

  • 2013
  • 2014
  • Final