How Nutrients and Flow Affect Structure and Succession in Artificial Stream Biofilms

EPA Grant Number: F6E61489
Title: How Nutrients and Flow Affect Structure and Succession in Artificial Stream Biofilms
Investigators: Larson, Chad A.
Institution: The University of Texas at Arlington
EPA Project Officer: Zambrana, Jose
Project Period: September 1, 2006 through September 1, 2008
Project Amount: $105,238
RFA: GRO Fellowships for Graduate Environmental Study (2006) RFA Text |  Recipients Lists
Research Category: Academic Fellowships , Aquatic Ecosystems , Fellowship - Aquatic Systems Ecology


Periphytic biofilms provide excellent study systems for examining how communities are assembled in space and time. In streams and rivers, periphytic biofilm communities are highly responsive to modifications in water flow and chemistry, resulting in substantial shifts in species abundance and richness. I will investigate how the anthropogenic effects of flow modification and eutrophication affect succession and community structure and function in stream biofilms in a series of experiments in recirculating artificial streams.


Periphytic biofilm communities grown in artificial streams will be subjected to different current and nutrient regimes. Species richness and diversity of biofilm communities accumulating on ceramic tiles will be examined with confocal and light microscopy. Genetic richness of biofilm communities will be determined using Terminal Restriction Fragment Length Polymorphism (T-RFLP) with phyto-specific 16S rDNA primers.

Expected Results:

Spatial heterogeneity and temporal fluctuation have long been recognized as powerful factors influencing species richness and complexity in ecological communities; I predict that species abundance and species richness of periphytic biofilm communities will differ between treatments varying current flow and nutrient abundance. Information obtained from this study will provide valuable insights into how ecological communities are structured and influenced by environmental variables. Additionally, as it becomes important to link species diversity and genetic diversity in ecosystems, I hope to provide insight to this question with the genetic data I obtain with T-RFLP analysis.

Supplemental Keywords:

Periphyton, algae, biofilm, nutrients, eutrophication, flow, confocal microscopy, T-RFLP, species richness, species diversity, primary productivity, biomass,, RFA, Scientific Discipline, ECOSYSTEMS, Ecosystem Protection/Environmental Exposure & Risk, Aquatic Ecosystems & Estuarine Research, Aquatic Ecosystem, Aquatic Ecosystems, Environmental Monitoring, Ecology and Ecosystems, eutrophication, nutrient dynamics, species interaction, periphytic biofilm, aquaculture, nutrient loading, ecosystem monitoring, anthropogenic impact

Progress and Final Reports:

  • 2007
  • Final