Technical Report

Final Report 2011 Effects of Nutrient Availability on Periphyton Growth and Diversity in the Middle Rio Grande: Top-Down and Bottom-Up Factors

URL: https://webapps.usgs.gov/mrgescp/documents/Bixby%20and%20Burdett_2011_Final%20Report%202011%20Effects%20of%20nutrient%20availability%20on%20periphyton%20growth%20and%20diversity%20in%20the%20MRG%20Top-down%20and%20bottom-up%20factors.pdf

Date: 2011/06/01

Author(s): Bixby R., Burdett A.

Publication: Prepared for U.S. Bureau of Reclamation, 79 p.

Abstract:

In lotic and lentic ecosystems, primary producers serve as a food resource for higher trophic levels. In the middle Rio Grande, invertebrate and fish grazers, including the federally endangered Rio Grande silvery minnow (Hybognathus amarus), are dependent on attached algae (periphyton) as a food resource. However, the relationships between environmental factors and algal biomass/community structure in the middle Rio Grande are poorly understood. In many aquatic systems, primary production is often limited by nutrient availability; it is not known how nutrient levels affect algal food resources for grazers in the Rio Grande or whether other factors limit productivity (e.g. high turbidity and decreased light penetration). Seasonal changes in precipitation also influence environmental parameters, including nutrients; periphyton may be limited by increased nutrient concentrations and turbidity levels.