From the GROUND UP
Effects of Herbicides on Mycorrhizal Fungi and Soil Ecosystems
Herbicides are chemicals that disrupt molecular pathways in plants determined to be invasive or otherwise troublesome. Their use is common in the fields of agriculture, landscaping, and restoration. One of the most widely applied herbicides, glyphosate ("Roundup"), has been introduced to environments across the United States. While glyphosate is targeted towards weedy plants, it also ends up in the soil and aquatic systems sometimes causing unintended damage to the environment. In this study we are investigating how glyphosate affects the structure and function of soil microbial communities (including mycorrhizal fungi), non-target plants, and soil health in general. This project will combine the use of tightly controlled lab microcosm experiments (already begun, see below) as well as field experiments to evaluate glyphosate's impact on the environment.
Funding for this project was made possible through a generous grant from the the Kristina and William Catto Foundation.
Project Team (bios): Emery Berry (high school student), Alison Orthel (Undergraduate), Emily Vander Pol (Undergraduate), Abby Tubman (Undergraduate), Michelle Hollenkamp (Undergraduate), Claire Mastrangelo (Undergraduate), Travis Pfeifer (Undergraduate), Kim Vincent (PhD student), Adam Solon (PhD student), Eli Gendron (PhD student), Cliff Bueno de Mesquita (Post Doc), and Steve Schmidt (Principal Investigator)
Herbicides are chemicals that disrupt molecular pathways in plants determined to be invasive or otherwise troublesome. Their use is common in the fields of agriculture, landscaping, and restoration. One of the most widely applied herbicides, glyphosate ("Roundup"), has been introduced to environments across the United States. While glyphosate is targeted towards weedy plants, it also ends up in the soil and aquatic systems sometimes causing unintended damage to the environment. In this study we are investigating how glyphosate affects the structure and function of soil microbial communities (including mycorrhizal fungi), non-target plants, and soil health in general. This project will combine the use of tightly controlled lab microcosm experiments (already begun, see below) as well as field experiments to evaluate glyphosate's impact on the environment.
Funding for this project was made possible through a generous grant from the the Kristina and William Catto Foundation.
Project Team (bios): Emery Berry (high school student), Alison Orthel (Undergraduate), Emily Vander Pol (Undergraduate), Abby Tubman (Undergraduate), Michelle Hollenkamp (Undergraduate), Claire Mastrangelo (Undergraduate), Travis Pfeifer (Undergraduate), Kim Vincent (PhD student), Adam Solon (PhD student), Eli Gendron (PhD student), Cliff Bueno de Mesquita (Post Doc), and Steve Schmidt (Principal Investigator)
Denver Botanic Gardens Chatfield Farms- location of our field experiment observing the effects of glyphosate-based herbicides on plants and soil microbes of non-native grassland.
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Team heading out to field site-
from L to R: Eli, Steve, Michelle, and Kim.
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Field experiment with rows of herbicide treatments and rows with no herbicide treatments.
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Staining mycorrhizae from roots collected at Chatfield Farms. L to R: Emery, Emily, and Alison.
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Overhead view of staining protocol.
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Above. Soil microcosms treated with glyphosate: (Left) an incubator with light and temperature controls to mimic field conditions, (Right) microcosms labelled according to treatment with temperature and light sensor probes intermixed. Below: a microcosm being examined microscopically (50x magnification), we will also use DNA sequencing techniques to determine how the microbial community is being affected.
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From top right (clockwise): pink fungi on a Chatfield Farms microcosm (45x magnification), green filament on Niwot microcosm (45x magnification), green cyanobacteria from Chatfield Farms microcosm (200x magnification, green cyanobacteria from Chatfield Farms microcosm (100x magnification)
Relevant publications:
McQueen PJ, K Gattoni, EMS Gendron, A Solon et al. 2024. Glyphosate-based restoration of a degraded grassland threatens soil health and the diversity of nematode communities. Soil Biology and Biochemistry 191: 109350. [Reprint]
Bueno de Mesquita CP, AJ Solon, A Barfield, CF Mastrangelo et al. 2023. Adverse impacts of Roundup on soil bacteria, soil chemistry, and mycorrhizal fungi during restoration of a Colorado grassland. Applied Soil Ecology 185: 104778. [Reprint]
Vincent, K., & Davidson, C. (2015). The toxicity of glyphosate alone and glyphosate–surfactant mixtures to western toad (Anaxyrus boreas) tadpoles. Environmental toxicology and chemistry, 34: 2791-2795.
McQueen PJ, K Gattoni, EMS Gendron, A Solon et al. 2024. Glyphosate-based restoration of a degraded grassland threatens soil health and the diversity of nematode communities. Soil Biology and Biochemistry 191: 109350. [Reprint]
Bueno de Mesquita CP, AJ Solon, A Barfield, CF Mastrangelo et al. 2023. Adverse impacts of Roundup on soil bacteria, soil chemistry, and mycorrhizal fungi during restoration of a Colorado grassland. Applied Soil Ecology 185: 104778. [Reprint]
Vincent, K., & Davidson, C. (2015). The toxicity of glyphosate alone and glyphosate–surfactant mixtures to western toad (Anaxyrus boreas) tadpoles. Environmental toxicology and chemistry, 34: 2791-2795.
