Lake Champlain Ecosystem Assessment

Important Open Water Habitats in Lake Champlain

The pelagic zone of the lake is the area where no sunlight penetrates to the bottom of the lake. This is the deepest part of the lake- over fifty feet, and contains minimal, if not any plant life. Cold water with high dissolved oxygen content can be found here and this zone is the most abundantly observed ecosystem in the lake, consisting of about eighty percent of all water volume of Lake Champlain (Berry). Cold water fish and free range plankton reside in these zones.

Diagram of lake zones

Deep water benthic zone is where most solar light cannot penetrate and is deeper than fifty feet. Here, decaying organic matter can be observed in the muddy substrate and various invertebrates such as crustaceans, insect larvae, phytoplankton, zooplankton, and aquatic worms reside. Some macrophytes- aquatic plants that float, hang, or grow upwards can also be found here and thirteen types of mollusks- specifically mussels, tend to be found in this benthic area.

Both of these aquatic habitats have remained in relatively good condition in the Lake Champlain Basin. They have the highest buffering capacities of any ecosystem in the lake; the size and volume of these zones has allowed them to respond the slowest to anthropogenic influences. Historically, little research has been conducted on the relationship, interactions(Vadeboncoeur et. al, 2002), and dynamics between the pelagic and benthic regions and their inhabitants and what services these two habitats contribute to the lake system as a whole. These two lake regions contain primary producer life forms and also have secondary consumer-predators, such as fish, that depend on the producers, bacteria, and primary consumers for food. As a habitat for charismatic and sought after species like lake trout, landlocked salmon, and sturgeon, these habitats are extremely important as a food resource for fish(Vadeboncoeur et. al). Proper understanding of the energy flows within and between these adjacent habitats is important because the abundance of food resources can become highly variable in one or both systems when outside pressures are introduced. Although these habitats are well buffered, they may become increasingly vulnerable to stress and invasive species if anthropogenic pressures continue at sustained rates in connected habitats like the littoral zone. Trophic relationships and biodiversity, like important fish species, could become severely affected as a result of these stresses.

Blue-green algae in Lake Champlain caused by high nutrient concentration

The Littoral zone (less than 50 ft) of the lake is a highly productive area of the Lake and hosts the most diverse and plentiful life in the lake (Berry). Located closest to the shores of Lake Champlain, this natural community has experienced the highest frequency of human-caused disturbances, which includes, but is not limited to: high nutrient concentrations (Hershener & Havens, 2008), pollution, alterations and losses of habitat structure, invasive species and global to regional climate change. These stresses may be caused by agriculture, flawed water diverging systems, deforestation, and human societal sprawl- all of which take place in close proximity to the lake edges or in the watersheds that drain in to the lake. Many of the littoral zones throughout Lake Champlain have already experienced rapid changes and have classified as in “poor” condition by the Nature Conservancy and other collaborators. These shoreline areas are located close to human civilization and play a large role in commercial, recreational, and drinking water use. Currently, there is no program for monitering many of the important and charismatic plant and animal species in the lake (Berry).

Sources

Berry, Tom. Conserving Lake Champlain’s Biological Diversity. Nature Conservancy. Retrieved from http://www.nature.org/wherewework/northamerica/states/vermont/files/lake_champlain_biodiversity_report.pdf.

Hershener, C. & Havens, K.J. (2008). Managing Invasive Aquatic Plants in a Changing System: Strategic Consideration of Ecosystem Services. Conservation Biology, 22(3), 7. Retrieved from http://www3.interscience.wiley.com/cgi-bin/fulltext/119879526/PDFSTART.

Vadeboncoeur, Y., Zanden, M.J., & Lodge, D.M. (2002). Putting the Lake Back Together: Reintegrating Benthic Pathways into Lake Food Web Models. Bioscience, 52(1) (2002): 44-54. Retrieved from  http://limnology.wisc.edu/personnel/jakevz/pdf/2002_Bioscience_VDBetal.pdf.