Winter-stratified monomictic lakes have only one period of mixing each year because they are very shallow in relation to its size and is completely exposed to winds. These lakes continue to circulate throughout the summer and typically never become thermally stratified in that season. They are only stratified in the winter when they freeze over and become inversely stratified (coldest water at the surface). With a surface area of nearly 80 square miles Oneida Lake is the largest winter-stratified monomictic lake in New York, and the largest lake entirely within New York State.
Very few lakes in NY have the physical setting to meet the large surface area and shallow depth thresholds that define the community (e.g., Lake Oneida). The condition of these lakes are threatened by nutrient and pollution runoff; and several aquatic invasive species. The current trend of this community is probably stable for actively protected/managed lakes, or declining slightly elsewhere due to moderate threats related to watershed development, invasive aquatic species, and alteration to the natural hydrology.
The number and acres of winter-stratified monomictic lakes in New York have likley remained stable in recent decades given that very few lakes in NY have the have the physical setting to meet the large surface to shallow depth ratio that define the community (e.g., Oneida Lake and Perch Lake). However, the water quality of these lakes is threatened by excessive run-off of nutrients, pathogens, and toxins from the surrounding watershed; and they are also threatened by the spread of numerous aquatic invasive species.
The number and acres of winter-stratified monomictic lakes in New York are probably comparable to historical numbers, but the water quality of several of these lakes has likely declined significantly as a result of several human caused disturbances (e.g., nutrient and pollution run-off, invasive species, watershed development, etc.).
Where practical, establish and maintain a lakeshore buffer to reduce storm-water, pollution, and nutrient run-off, while simultaneously capturing sediments before they reach the lake. Buffer width should take into account the erodibility of the surrounding soils, slope steepness, and current land use. If possible, minimize the number and size of impervious surfaces in the surrounding landscape. Avoid habitat alteration within the lake and surrounding landscape. For example, roads should not be routed through the lakeshore buffer area. If a lake must be crossed, then bridges and boardwalks are preferred over filling and culverts. Restore lakes that have been affected by unnatural disturbance (e.g., remove obsolete impoundments and ditches in order to restore the natural hydrology). Prevent the spread of invasive exotic species into the lake through appropriate direct management, and by minimizing potential dispersal corridors. Look for more lake-specific information on this topic in the following reports and management plans: Oneida Lake State of the Lake and Watershed Report (Central New York Regional Planning and Development Board 2003) and Oneida Lake Watershed Management Plan (Central New York Regional Planning and Development Board 2004).
These lakes are threatened by the spread of aquatic invasive species, such as common carp (Cyprinus carpio), zebra mussel (Dreissena polymorpha), bloody red shrimp (Hemimysis anomala), Eurasian watermilfoil (Myriophyllum spicatum), variable leaf watermilfoil (Myriophylluum heterophyllum), and curly-leaved pondweed (Potamogeton crispus).
Threats to water quality in Lake Oneida include the following (excerpted from the Oneida Lake Watershed Management Plan): Water chestnut was first detected in Lake Oneida in 1999. Dense plant growth on the lake surface blocks the sunlight from penetrating the water column, shades out native plants, reduces fish habitat, and restricts boating and other recreational usage. Zebra mussels were first detected in Lake Oneida in 1991. These organisms have dramatically changed water clarity patterns in Oneida Lake and have caused the extinction of all native clams. Zebra mussel induced water clarity patterns have resulted in aquatic plant growth extending into deeper water and have likely impacted the behavior and abundance of turbid water fish species like walleye. Increased light penetration has caused mats of algae to grow on the lake bottom at shallow depths and windrows of aquatic plants and algae to accumulate on the shoreline in late summer and early fall. Boating pressures: Overuse of the lake by boaters and other watercraft is a concern. Salt application and storage: The application of deicing salts on roadways and unprotected salt storage areas can impact both surface water and groundwater. High salt content in groundwater and surface water can alter water chemistry, making it unfit for aquatic life or human consumption. Septic systems and other human influences: While phosphorus levels and nutrient enrichment have declined in Oneida Lake over the past 20 years, nutrients and other elements originating from agricultural and street runoff and poorly maintained septic systems remain a concern. Erosion: The loss of soil from the Oneida Lake watershed due to poor land use practices associated with agriculture, forestry, highway maintenance, and construction is a major issue of concern especially in the southern portion of the watershed. Loss of soil into Oneida Lake destroys valuable fish habitat and introduces nutrients and other pollutants to the lake. Sedimentation: Excess sediment loading at the mouth of tributaries and in Oneida Lake can result in negative impacts on aquatic biota, fish, and fish habitat. As areas of the lake bottom become shallow as a result of heavy sedimentation, boating and other recreational activities are greatly hampered. Flooding: Flooding occurs in the regions surrounding Oneida Lake, often after major storm events or rapid winter thaws. Lake water levels: Problems within the lake community can develop if the lake water levels are either too high or too low.
Where practical, establish and maintain a lake shore buffer to reduce storm-water, pollution, and nutrient run-off, while simultaneously capturing sediments before they reach the lake. Buffer width should take into account the erodibility of the surrounding soils, slope steepness, and current land use. If possible, minimize the number and size of impervious surfaces in the surrounding landscape. Avoid habitat alteration within the lake and surrounding landscape. For example, roads should not be routed through the lake shore buffer area. If portions of a lake must be crossed, then bridges and boardwalks are preferred over filling and culverts. Restore lakes that have been affected by unnatural disturbance (e.g., remove obsolete impoundments and ditches in order to restore the natural hydrology). Prevent the spread of invasive exotic species into the lake through appropriate direct management, and by minimizing potential dispersal corridors.
When considering road construction and other development activities, minimize actions that will change what water carries and how water travels to this lake community, both on the surface and underground. Water traveling over-the-ground as run-off usually carries an abundance of silt, clay, and other particulates during (and often after) a construction project. While still suspended in the water, these particulates make it difficult for aquatic animals to find food; after settling to the bottom of the lake, these particulates bury small plants and animals and alter the natural functions of the community in many other ways. Thus, road construction and development activities near this lake type should strive to minimize particulate-laden run-off into this community. Water traveling on the ground or seeping through the ground also carries dissolved minerals and chemicals. Road salt, for example, is becoming an increasing problem both to natural communities and as a contaminant in household wells. Fertilizers, detergents, and other chemicals that increase the nutrient levels in lakes cause algae blooms and eventually an oxygen-depleted environment where few animals can live. Herbicides and pesticides often travel far from where they are applied and have lasting effects on the quality of the natural community. So, road construction and other development activities should strive to consider: 1. how water moves through the ground, 2. the types of dissolved substances these development activities may release, and 3. how to minimize the potential for these dissolved substances to reach this natural community. Look for more lake-specific information on this topic in the following reports and management plans: Oneida Lake State of the Lake and Watershed Report (Central New York Regional Planning and Development Board 2003) and Oneida Lake Watershed Management Plan (Central New York Regional Planning and Development Board 2004).
Resurvey known occurrences and search for new occurrences statewide to advance documentation and classification of winter-stratified monomictic lakes. A statewide review of winter-stratified monomictic lakes is desirable. Continue searching for large lakes in good condition (A- to AB-ranked). Review and incorporate data from partner organizations to create a new occurrence record of winter-stratified monomictic lake for Oneida Lake, and to update the Perch Lake and Horseshoe Lake occurrrences (e.g., Central New York Regional Planning and Development Board). Review and incorporate data on occurrences in NY gathered by the Adirondack Lakes Survey Corporation, the Adirondack Park Invasive Plant Program, and the New York State Federation of Lake Associations, Inc.
There is a need to research the composition of winter-stratified monomictic lakes statewide in order to characterize variations. Only two to three ecoregional variants are suspected (Great Lakes, Northern Appalachian, and possibly Lower New England types), potentially differing in dominant, and characteristic vascular plants, fishes, mollusks, and insects.
This community is uncommon in upstate New York, north of the North Atlantic Coast Ecoregion. Probably limited to the Great Lakes Ecoregion and adjacent parts of other ecoregions such as the Northern Appalachians and concentrated in or restricted to non-mountainous areas of the state.
This broadly-defined community may be worldwide. Examples with the greatest biotic affinities to New York occurrences are suspected to span north to southern Canada, west to Minnesota, southwest to Indiana and Tennessee, and southeast to North Carolina.
Winter-stratified monomictic lakes have only one period of mixing each year because they are very shallow in relation to its size and is completely exposed to winds. These lakes continue to circulate throughout the summer and typically never become thermally stratified in that season. They are only stratified in the winter when they freeze over and become inversely stratified (coldest water at the surface). With a surface area of nearly 80 square miles (207 sq. km.) Oneida Lake is the largest winter-stratified monomictic lake in New York. The lake is about 21 miles (34 km) long and about 5 miles (8.0 km) wide with an average depth of 22 feet (6.7 m).
Characteristic fishes are walleye (Stizostedion vitreum), largemouth bass (Micropterus salmoides), yellow perch (Perca flavescens), bullhead (Ictalurus spp.), white sucker (Catostomus commersoni), muskellunge (Esox masquinongy), and trout perch (Percopsis omiscomaycus). Characteristic macroinvertebrates may include isopods (Isopoda), amphipods (Amphipoda), and ramshorn snails (Planorbidae). Characteristic phytoplankton may include Dinobryon spp., and Ceratium spp. Vascular plants are typically diverse. Characteristic aquatic macrophytes include water stargrass (Heteranthera dubia), coontail (Ceratophyllum demersum), waterweed (Elodea spp.), naiad (Najas flexilis), tapegrass (Vallisneria americana), and pondweeds (Potamogeton perfoliatus, P. pectinatus, P. pusillus, P. richardsonii, P. nodosus, P. zosteriformis). The macroalgae Chara may be abundant.
Winter-stratified monomictic lakes can be easily observed from the shoreline where there is public access, or by boat during calm weather.
Percent cover
This figure helps visualize the structure and "look" or "feel" of a typical Winter-stratified Monomictic Lake. Each bar represents the amount of "coverage" for all the species growing at that height. Because layers overlap (shrubs may grow under trees, for example), the shaded regions can add up to more than 100%.
Berg, C.O. 1963. Middle Atlantic states. Chapter 6 from Limnology in North America. The University of Wisc. Press.
Bloomfield, J.A., ed. 1978a. Lakes of New York State. Vol. I. Ecology of the Finger Lakes. Academic Press, New York.
Central New York Regional Planning and Development Board. 2003. Oneida Lake State of the Lake and Watershed Report. Central New York Regional Planning and Development Board, Syracuse, NY.
Central New York Regional Planning and Development Board. 2004. A Management Strategy for Oneida Lake and Its Watershed. Central New York Regional Planning and Development Board, Syracuse, NY.
Edinger, G. J., D. J. Evans, S. Gebauer, T. G. Howard, D. M. Hunt, and A. M. Olivero (editors). 2014. Ecological Communities of New York State. Second Edition. A revised and expanded edition of Carol Reschke’s Ecological Communities of New York State. New York Natural Heritage Program, New York State Department of Environmental Conservation, Albany, NY. https://www.nynhp.org/ecological-communities/
Hunt, David M. 1998. Community ranking and general description. Lake Champlain, summer-stratified monomictic lake. Unpublished report. New York Natural Heritage Program, New York State Department of Environmental Conservation. Latham, NY.
New York Natural Heritage Program. 2023. New York Natural Heritage Program Databases. Albany, NY.
Nichols, W. F. 2015. Natural Freshwater Lakes and Ponds in New Hampshire: Draft Classification. NH Natural Heritage Bureau, Concord, NH.
Olivero-Sheldon, A. and M.G. Anderson. 2016. Northeast Lake and Pond Classification. The Nature Conservancy, Eastern Conservation Science, Eastern Regional Office. Boston, MA.
This guide was authored by: Gregory J. Edinger
Information for this guide was last updated on: June 2, 2021
Please cite this page as:
New York Natural Heritage Program. 2023.
Online Conservation Guide for
Winter-stratified monomictic lake.
Available from: https://guides.nynhp.org/winter-stratified-monomictic-lake/.
Accessed September 23, 2023.