Agricultural Pesticides Could Be Impacting the Natural Beauty at Sequoia National Park Through Atmospheric Deposition
High up in the remote alpine and subalpine lakes of Sequoia and Kings Canyon National Park (SEKI), the crystal-clear lakes appear to be greening with an overpopulation of periphyton. Periphyton is a mixture of various water microbes such as algae, cyanobacteria, and others. Scientists at the USGS Columbia Environmental Research Center and the University of Missouri are working with National Park scientists to learn why.
Why is this important
One possible cause of SEKI’s periphyton blooms is atmospheric deposition of nitrogen and copper, which are often associated with agricultural use; previous research predicted that copper is a likely agricultural contaminant that drifts into Sierra Nevada lakes (Meyer and DeMars 2018).
These lakes are delicate oases in a beautiful but barren landscape and create livable space for unique creatures that cannot survive anywhere else in the park. Protecting these integral parts of the SEKI ecosystem is a high priority for the National Park.
An Adventurous Journey
The best way to understand if nitrogen and copper are getting into remote environments is to go there and see what’s going on in person. To test their hypotheses, the scientific team conducted a series of multi-day sampling expeditions at six lakes in the rugged and remote wilderness of Sequoia National Park.
To get to base camp at Pear Lake, the team hiked twelve miles (round trip) and ascended to an elevation of 9550 feet. Mules and large backpacks were required to bring all the necessary gear. To get a good sample size, the team traveled to six alpine and subalpine lakes. They collected water, sediment, periphyton, fish and, tadpole samples for copper and nitrogen measurements, and they placed sensors for continuous data logging of temperature, dissolved oxygen, pH, and conductivity. This was done once a month from June through October to gather an entire season’s data and repeated for two years (2021-2022).
Periphyton Experiment in Pear Lake
In addition to the monitoring objectives, the scientific team tested how combinations of copper and nitrogen affect periphyton growth. To do this, they added agar containing copper and nitrate at various concentrations to containers that were placed in Pear Lake. A substrate placed on top of the agar provided a surface for the periphyton to grow on. The periphyton that grew on the substrate was measured for density and diversity. Measuring the diversity was done by extracting DNA from the periphyton and sequencing it to get an inventory of the species that make up the Pear Lake periphyton community.
In addition, these samples of periphyton were tested for concentrations of copper using inductively coupled plasma mass spectrometry. The results were compared among different treatment levels and to the scientific literature on the topic.
The team also collected tissue samples from native tadpoles and fish to assess copper accumulation and possible health effects in these animals.
Continued study on the topic will help us better understand algal blooms in remote alpine water bodies and alert researchers to possible underlying causes. Sequoia National Park can use this research to inform management of their natural resources.
Project Leads: Gaby Ruso (PhD Dissertation, University of Missouri), Kelly Martin (Master’s Thesis, Fresno State University)
Team: Thea Edwards, Erik Meyer, Lisa Webb, Craig Paukert, Katie D’Agastino, Jordan French, Izzy Christy, Rachel Lurz, Lillie Bradshaw, Satomi Kohno, and additional USGS and National Park Service staff
Partnering
Sequoia and Kings Canyon National Parks, University of Missouri, USGS Missouri Cooperative Fish and Wildlife Research Unit, USGS Columbia Environmental Research Center. The Center for Reservoir and Aquatic Systems Research at Baylor University. All photos were produced by USGS CERC
References
Meyer, E. W., and C. DeMars. 2018. A simplified approach to using pesticide use reporting to prioritize pesticide risk in California's national parks. Pages 405-430 in Managing and analyzing pesticide use data for pest management, environmental monitoring, public health, and public policy. Zhang, M., S. Jackson, M. A. Robertson, and M. R. Zeiss, Eds. American Chemical Society, Washington, DC, USA.
High up in the remote alpine and subalpine lakes of Sequoia and Kings Canyon National Park (SEKI), the crystal-clear lakes appear to be greening with an overpopulation of periphyton. Periphyton is a mixture of various water microbes such as algae, cyanobacteria, and others. Scientists at the USGS Columbia Environmental Research Center and the University of Missouri are working with National Park scientists to learn why.
Why is this important
One possible cause of SEKI’s periphyton blooms is atmospheric deposition of nitrogen and copper, which are often associated with agricultural use; previous research predicted that copper is a likely agricultural contaminant that drifts into Sierra Nevada lakes (Meyer and DeMars 2018).
These lakes are delicate oases in a beautiful but barren landscape and create livable space for unique creatures that cannot survive anywhere else in the park. Protecting these integral parts of the SEKI ecosystem is a high priority for the National Park.
An Adventurous Journey
The best way to understand if nitrogen and copper are getting into remote environments is to go there and see what’s going on in person. To test their hypotheses, the scientific team conducted a series of multi-day sampling expeditions at six lakes in the rugged and remote wilderness of Sequoia National Park.
To get to base camp at Pear Lake, the team hiked twelve miles (round trip) and ascended to an elevation of 9550 feet. Mules and large backpacks were required to bring all the necessary gear. To get a good sample size, the team traveled to six alpine and subalpine lakes. They collected water, sediment, periphyton, fish and, tadpole samples for copper and nitrogen measurements, and they placed sensors for continuous data logging of temperature, dissolved oxygen, pH, and conductivity. This was done once a month from June through October to gather an entire season’s data and repeated for two years (2021-2022).
Periphyton Experiment in Pear Lake
In addition to the monitoring objectives, the scientific team tested how combinations of copper and nitrogen affect periphyton growth. To do this, they added agar containing copper and nitrate at various concentrations to containers that were placed in Pear Lake. A substrate placed on top of the agar provided a surface for the periphyton to grow on. The periphyton that grew on the substrate was measured for density and diversity. Measuring the diversity was done by extracting DNA from the periphyton and sequencing it to get an inventory of the species that make up the Pear Lake periphyton community.
In addition, these samples of periphyton were tested for concentrations of copper using inductively coupled plasma mass spectrometry. The results were compared among different treatment levels and to the scientific literature on the topic.
The team also collected tissue samples from native tadpoles and fish to assess copper accumulation and possible health effects in these animals.
Continued study on the topic will help us better understand algal blooms in remote alpine water bodies and alert researchers to possible underlying causes. Sequoia National Park can use this research to inform management of their natural resources.
Project Leads: Gaby Ruso (PhD Dissertation, University of Missouri), Kelly Martin (Master’s Thesis, Fresno State University)
Team: Thea Edwards, Erik Meyer, Lisa Webb, Craig Paukert, Katie D’Agastino, Jordan French, Izzy Christy, Rachel Lurz, Lillie Bradshaw, Satomi Kohno, and additional USGS and National Park Service staff
Partnering
Sequoia and Kings Canyon National Parks, University of Missouri, USGS Missouri Cooperative Fish and Wildlife Research Unit, USGS Columbia Environmental Research Center. The Center for Reservoir and Aquatic Systems Research at Baylor University. All photos were produced by USGS CERC
References
Meyer, E. W., and C. DeMars. 2018. A simplified approach to using pesticide use reporting to prioritize pesticide risk in California's national parks. Pages 405-430 in Managing and analyzing pesticide use data for pest management, environmental monitoring, public health, and public policy. Zhang, M., S. Jackson, M. A. Robertson, and M. R. Zeiss, Eds. American Chemical Society, Washington, DC, USA.