This project is researching lakes with and without carp to determine how carp impact carbon sequestration and greenhouse gas emissions, and determine the climate change and economic benefits of carp removal.
Objectives. The objectives of this project are to determine how carp affect carbon sequestration and greenhouse gas emissions from 18 Minnesota lakes and determine both the climate change and economic benefits of carp removal.
The project team will analyze 18 lakes:
- With established, abundant (>100 kg/ha) carp
- Where carp have been eradicated
- Lakes in which carp have not been detected by fish monitoring
Scientists will measure the abundance of carp and aquatic macrophytes in the 18 lakes and estimate sediment accumulation rates and greenhouse gas emissions, including carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O).
Why. Carp are known to be deleterious to the social value and quality of lake water, but it's quantitatively unknown how carp affect the accumulation of carbon (C) in lake sediment and how carp might exacerbate greenhouse gas emissions.
Who. The project team's goal is to provide analyses that gives lake managers at the Minnesota Department of Natural Resources, other agencies, tribes, and policy makers the applied tools they can use to determine how to optimally apply carp management to Minnesota lakes.
Progress update: August 2024
In the summer of 2023, MAISRC researchers set up a network of 18 lakes with varying levels of carp infestation and began collecting samples for fish, macrophytes, and water chemistry. The fieldwork was completed by August, and data analysis on carp and macrophyte abundance, along with water chemistry, started soon after.
Starting in October 2023, researchers expanded their fieldwork to include sediment core sampling from each lake. These cores are intended to assess the impact of carp on nutrient and carbon mobility within the sediments. By mid-November, sediment coring was complete, and the winter was spent performing phosphorus fractionation on the top 40 cm of each core. This spring and summer, they processed these samples to measure water and carbon content, partnering with the St. Croix Watershed Research Station to date the cores and estimate carbon burial rates. Two cores have already been sent for dating, with the rest scheduled to follow soon. The final carbon burial estimates are expected by early 2025, which will help compare carbon levels in lakes with and without carp.
This summer, MAISRC researchers have continued their focus on CO2 and CH4 emissions, emphasizing spatial and temporal sampling. They are using deployable pH loggers to track overnight CO2 emission trends and will continue monitoring the 18 lakes through August.