Use of phosphorus to reduce blooms of the benthic diatom Didymosphenia geminata in an oligotrophic stream

Freshwater Science
By: , and 

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Abstract

Blooms of the benthic alga, Didymosphenia geminata [Lyngbye (Schmidt)], were first documented in Rapid Creek, South Dakota, in 2002 and have since been associated with changes to aquatic resources. Low concentration of P has been associated with D. geminata stalk development (i.e., blooms), so we considered elevating P as a possible method to reduce D. geminata blooms. We conducted 2 whole-stream P-enrichment experiments in Rapid Creek during 2007 and 2008. Enrichment with a slow-release fertilizer (Osmocote®: 14-14-14) in 2007 significantly reduced D. geminata blooms (indexed by D. geminata biomass) compared to upstream control sites. The reduction in biomass was less pronounced as distance from the enrichment source increased, a result indicating that P augmentation effectively decreased D. geminata biomass. In 2008, we implemented a before-after–control-impact (BACI) study to assess effects of a quick-release fertilizer (MAP: 11-52-0) on D. geminata biomass. The addition of 6 μg/L P to Rapid Creek resulted in a significant decrease in D. geminata biomass within 0.6 km downstream of the nutrient-addition point. Effects on D. geminata biomass were not evident further downstream. This study provides evidence to support the hypothesis that low P concentration regulates D. geminata blooms.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Use of phosphorus to reduce blooms of the benthic diatom Didymosphenia geminata in an oligotrophic stream
Series title Freshwater Science
DOI 10.1086/683038
Volume 34
Issue 4
Year Published 2015
Language English
Publisher The University of Chicago Press
Contributing office(s) Coop Res Unit Leetown
Description 10 p.
First page 1272
Last page 1281