Clean Water

The diverse ecosystems, working
landscapes, and vibrant communities
that inspire and sustain us depend on
clean water. Learn about pollution
reduction strategies.

Healthy Habitats
Connect Us All

Lakeshores, stream banks, and wetlands are critical to clean
water and biodiversity. Learn about efforts to improve
habitat connectivity in the Basin ecosystem.

We Care for
What We Know

Recreation fosters stewardship of the Basin’s rich
natural and cultural heritage by connecting people
to the landscape while supporting local economies.
Learn about ways to explore the Basin.

Informed Citizens
Make Wiser Choices

Citizens who have an understanding and
appreciation of water resources make informed
choices about actions that might contribute to
pollution. Learn about education programs.

    Water & Environment

    Did You Know?

    More than 300 shipwrecks have been found in Lake Champlain. Some of these shipwrecks are in the Lake Champlain Underwater Historic Preserve and can be visited by scuba divers.
    Find out more


    white perch and zooplankton

    White perch and daphnia (zooplankton) found in its stomach. Photos: Mary Watzin

    Phytoplankton and zooplankton form the base of Lake Champlain’s food web, sometimes called the ‘lower food web.’ These microscopic floating plants, animals, and bacteria are the most numerous and most simple organisms. Complex predator-prey relationships lead to the top of the food web—predator fish such as largemouth bass, northern pike, lake trout, and salmon, and the people and animals that fish for these species. Forage fish, such as smelt and minnows, link the plankton community and the predator fish. Most fish, including predatory fish, feed directly on the plankton community when they are young.

    Plankton communities are dynamic and strongly influenced by changes in their physical environment (often referred to as ‘bottom-up’ effects). Phytoplankton are microscopic plants—they require sunlight for photosynthesis for energy and nutrients, including phosphorus, to grow. In environments where there is excess phosphorus, phytoplankton, or algae, may grow abundantly. This can lead to algal blooms and is one of the reasons our water resource management efforts are focused on reducing phosphorus. Other environmental factors, such as temperature, also can influence phytoplankton growth. Cyanobacteria (blue-green algae), for example, prefer warmer water, thus increased temperatures that are predicted for the future may result in more cyanobacteria blooms. In Lake Champlain, cyanobacteria blooms frequently occur in areas with the highest phosphorus concentrations. Increasing phosphorus concentrations in other parts of the lake, coupled with notably warmer summer days, may contribute to the increasing number of blooms reported each year lake-wide.

    Zooplankton are the “animal” brethren of phytoplankton. They also are small, single-celled organisms, but typically prey on phytoplankton and other microscopic organisms in the water column. Zooplankton also respond to bottom-up effects—fewer phytoplankton means less food, and changes in the type of phytoplankton may mean less good food is available for certain species of zooplankton. This, in turn, affects the fish that eat the zooplankton and so on up the food chain to the largest predators in the lake, such as Atlantic salmon and lake trout. ‘Top-down’ effects, such as changes in the predators that eat zooplankton, also can be very important. For example, large populations of zooplankton-eating (zooplanktivorous) fish will reduce zooplankton populations, which will result in less predation pressure on algae (phytoplankton). As a result, water clarity may decrease or more algal blooms may occur.

    Changes in the Lake Champlain ecosystem as a result of invasive species have affected plankton communities in the Lake. Filter-feeding invasive zebra mussels consume large quantities of select plankton species, which has led to an increase in lake water clarity in shallow water and alters the food supply for fish and zooplankton that prefer these species as a food source. However, zebra mussels do not eat cyanobacteria, the plankton that cause the harmful algae blooms that are now common in some parts of Lake Champlain. The reduced competition for available nutrietnts and sunlight allows for cyanobacteria to flourish and bloom more frequently. Spiny water flea, an invasive crustacean found the Champlain Canal and Lake George in 2012, has the potential to disrupt the plankton communities in Lake Champlain by eating or outcompeting plankton, potentially affecting the entire food web.

    Plankton Monitoring in Lake Champlain

    Researchers at several academic institutions and State and Provincial agencies in the region are working to increase our understanding of this broad group of plants and animals. The Long-Term Water Quality and Biological Monitoring Project for Lake Champlain (LTMP) includes monitoring of plankton at 15 lake stations between April and October each year. Monitoring program staff count, identify, and measure phytoplankton and zooplankton at each of these stations. The Lake Champlain Research Institute at SUNY Plattsburgh, with funding from LCBP as part of the Lake Champlain Long-Term Monitoring Program, has documented several shifts in plankton community over the past few decades as new invasive species arrive and flourish in Lake Champlain and others decline. Continued monitoring and research of this important part of the Lake Champlain ecosystem is critical to understanding and predicting changes to the ecosystem as new species arrive, others decline, and our climate changes. To learn more about this program and view data, visit the LTMP website and view the “Biological Data Graphs” in the right column.

    Phytoplankton ID Guides

    Zooplankton ID Guides

    More on Plankton

    For more information on how the Lake Champlain food web—including plankton—is changing, please visit our State of the Lake website.


    What is the State of the Lake?

    What is the
    State of the Lake?

    Learn about the health of Lake Champlain in the 2018 State of the Lake report. Read about trends in key indicators of water quality and ecosystem health. Read the State of the Lake report


    Make Some Waves

    From using lake-friendly cleaning products to volunteering with a local watershed group, you can help restore and protect the Lake Champlain Basin. Find out how you can get involved

    Track Our Progress

    Track Our Progress

    Explore the goals and actions of our partners and track our progress online with the Opportunities for Action website. View Opportunities for Action

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    LCBP is a program partner of
    Lake Champlain Basin Program

    Lake Champlain Basin Program
    54 West Shore Road
    Grand Isle, VT 05458
    800-468-5227 (NY & VT)
    or 802-372-3213