Effects of 2 fungicide formulations on microbial and macroinvertebrate leaf decomposition under laboratory conditions

Environmental Toxicology and Chemistry
By: , and 

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Abstract

Aquatic fungi contribute significantly to the decomposition of leaves in streams, a key ecosystem service. However, little is known about the effects of fungicides on aquatic fungi and macroinvertebrates involved with leaf decomposition. Red maple (Acer rubrum) leaves were conditioned in a stream to acquire microbes (bacteria and fungi), or leached in tap water (unconditioned) to simulate potential reduction of microbial biomass by fungicides. Conditioned leaves were exposed to fungicide formulations QUILT (azoxystrobin + propiconazole) or PRISTINE (boscalid + pyraclostrobin), in the presence and absence of the leaf shredder, Hyalella azteca (amphipods; 7-d old at start of exposures) for 14 d at 23 °C. QUILT formulation (~ 0.3 μg/L, 1.8 μg/L, 8 μg/L) tended to increase leaf decomposition by amphipods (not significant) without a concomitant increase in amphipod biomass, indicating potential increased consumption of leaves with reduced nutritional value. PRISTINE formulation (~ 33 μg/L) significantly reduced amphipod growth and biomass (p<0.05), effects similar to those observed with unconditioned controls. The significant suppressive effects of PRISTINE on amphipod growth, and the trend towards increased leaf decomposition with increasing QUILT concentration, indicate the potential for altered leaf decay in streams exposed to fungicides. Further work is needed to evaluate fungicide effects on leaf decomposition under conditions relevant to stream ecosystems, including temperature shifts and pulsed exposures to pesticide mixtures.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Effects of 2 fungicide formulations on microbial and macroinvertebrate leaf decomposition under laboratory conditions
Series title Environmental Toxicology and Chemistry
DOI 10.1002/etc.3465
Volume 35
Issue 11
Year Published 2016
Language English
Publisher Wiley
Contributing office(s) New Jersey Water Science Center, California Water Science Center, Oregon Water Science Center, Leetown Science Center
Description 11 p.
First page 2834
Last page 2844
Country United States