Summary

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Summer-stratified monomictic lakes are so deep (or large) that they have only one period of mixing or turnover each year (monomictic), and one period of stratification. These lakes are typically thermally stratified only in the summer (warmest water at the surface). Lake Champlain, Cayuga Lake, and Seneca Lake are the three largest summer-stratified monomictic lakes in New York. Seneca Lake is the largest of the Finger Lakes, and the deepest lake entirely within the state with an average depth of 291 feet (89 m) and maximum depth of 618 feet (188 m). Because of Seneca Lake's great depth its temperature remains a near-constant 39 °F (4 °C). In summer the top 10 to 15 feet (3.0 to 4.6 m) warms to 70–80 °F (21–27 °C).

State Ranking Justification

Very few lakes in NY have the physical setting to meet the minimum size and depth thresholds that define the community (e.g., Lake Champlain, Cayuga Lake, and Seneca Lake). The condition of these lakes are threatened by nutrient and pollution runoff; and numerous aquatic invasive species.

Short-term Trends

The number and acres of summer-stratified monomictic lakes in New York have likley remained stable in recent decades given that very few lakes in NY have the physical setting to meet the minimum size and depth thresholds that define the community (e.g., Lake Champlain, Cayuga Lake, and Seneca 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.

Long-term Trends

The number and acres of summer-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.).

Conservation and Management

Conservation Overview

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 management plans: Opportunities for Action for Lake Champlain (LCBP 2017), Seneca Lake Watershed Management Plan (Genesee/Finger Lake Regional Planning Council 2012), and Cayuga Lake Watershed Restoration and Protection Plan (Cayuga Lake Watershed Network. 2017).

Threats

Threats to water quality in Lake Champlain include the following: Nutrient Pollution: Excess phosphorus combined with warm temperatures and calm conditions can sometimes result in toxic cyanobacteria blooms. Most of the phosphorus comes from runoff from developed areas, lawns, and farms. Pathogens: Disease-causing bacteria, viruses, and parasites are present in human and animal waste. During rain events, runoff carries Escherichia coli (E. coli), giardia, cryptosporidiosis, and flatworms into streams and rivers and eventually the lakes. Agricultural fields, faulty septic systems, and pet waste are common sources of pathogens. Toxic Substances: polychlorinated biphenyls (PCB), mercury, dioxins/furans, chlorinated phenols, persistent organics, solvents; pesticides (herbicides, insecticides, fungicides); pharmaceuticals and personal care products (medications, antibiotics, antidepressants, fragrances, surfactants, detergent metabolites, antimicrobial additives), trace elements (arsenic, manganese, cadmium, chromium, lead, nickel, silver, zinc, copper); road de-icing salts; cyanobacterial toxins (aycrocystin, anatoxin).

Seneca Lake is threatened by pollution and runoff from the following sources: agricultural activities, forestry, urban landscapes, chemical and petroleum storage, spills, landfills and solid waste disposal, mining activities, road salt, road-bank erosion, boating activities, onsite and municipal liquid waste disposal, storm water runoff, construction activities, energy development, and air quality.

Threats to water quality in Cayuga Lake include agricultural activity, wastewater sources, and other contributors of nutrients in the watershed. Elevated nutrient and chlorophyll levels in the lake tend to be correlated with the formation of disinfection by-products (DBPs) in finished potable water that would require advanced treatment to meet drinking water standards. DBPs are formed when disinfectants such as chlorine used in water treatment plants react with natural organic matter (i.e., decaying vegetation) present in the source water. Sediment eroded from the landscape enters the extensive surface drainage network in the Cayuga Lake watershed and ultimately is transported to Cayuga Lake.

Summer-stratified monomictic lakes are threatened by the spread of numerous aquatic invasive species, such as alewife (Alosa pseudoharengus), mud bithynia (Bithynia tentaculata), spiny water flea (Bythotrephes longimanus), fishhook waterflea (Cercopagis pengoi), Asian clam (Corbicula fluminea), common carp (Cyprinus carpio), quagga mussel (Dreissena bugensis), zebra mussel (Dreissena polymorpha), scud (Echinogammarus ischnus), bloody red shrimp (Hemimysis anomala), European frogbit (Hydrocharis morsus-ranae), Eurasian watermilfoil (Myriophyllum spicatum), variable leaf watermilfoil (Myriophylluum heterophyllum), brittle naiad (Najas minor), round goby (Neogobius melanostomus), greater European peaclam (Pisidium amnicum), Curly leafed pondweed (Potamogeton crispus), European ear snail (Radix auricularia), rudd (Scardinius erythrophthalmus), tench (Tinca tinca), water chestnut (Trapa natans), and European valve snail (Valvata piscinalis)

Conservation Strategies and Management Practices

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.

Development and Mitigation Considerations

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 management plans: Opportunities for Action for Lake Champlain (LCBP 2017), Seneca Lake Watershed Management Plan (Genesee/Finger Lake Regional Planning Council 2012), and Cayuga Lake Watershed Restoration and Protection Plan (Cayuga Lake Watershed Network. 2017).

Inventory Needs

Review and incorporate data from partner organizations to create new occurrence records of summer-stratified monomictic lake for Seneca Lake and Cayuga Lake, and to update the Lake Champlain occurrrence (e.g., Lake Champlain Basin Program, Cayuga Lake Watershed Network, and Genesee/Finger Lake Regional Planning Council).

Research Needs

There is a need to research the composition of summer-stratified monomictic lakes statewide in order to characterize variations. Up to two ecoregional variants are possible (St. Lawrence-Lake Champlain, and Finger Lakes types) with one to few examples of each, potentially differing in dominant, and characteristic vascular plants, fishes, mollusks, and insects.

Research needs for Lake Champlain: 1) Identify critical source regions for nutrient inputs, and most cost-effective ways to reduce inputs - so that management actions can be targeted more effectively and with greater cost efficiency; 2) Improve understanding of biodiversity, including food web dynamics, the impact of non-native species, and potential impacts of climate change; 3) Improve understanding of toxins, including “new-generation” contaminants and their potential impacts; and 4) Improve understanding of water circulation patterns within and among sub-basins – especially in areas with high nutrient levels. This includes continuation, and possible expansion, of meteorological stations needed to monitor wind and weather conditions (Lake Champlain Research Consortium 2008).

Research needs for Seneca Lake include monitoring water quality indicators including the following: number and types of macroinvertebrates; invasive species; algae species that cause harmful algal blooms; excessive erosion and polluted run-off; heavy metals such as mercury; air quality over the watershed; silicates; salt concentrations; water temperatures at various depths; seasonal changes at various depths; viruses that infect aquatic animals such as game fish, and many others (Seneca Lake Pure Waters Association 2017).

Research needs for Cayuga Lake include the following: continue critical water quality monitoring in tributaries of the northern Cayuga Lake watershed; determine the precise sources of nutrient-loading to the lake, that can lead to harmful algal blooms, by using specific bacteria as tracers (SUNY College of Environmental Science and Forestry).

Rare Species

• Ardea alba (Great Egret) (guide)
• Gavia immer (Common Loon) (guide)
• Stuckenia filiformis ssp. alpina (Slender Pondweed) (guide)

Range

New York State Distribution

This community is uncommon in upstate New York, north of the North Atlantic Coast Ecoregion. Probably restricted the larger Finger Lakes in the the Great Lakes Ecoregion and the Lake Champlain Valley.

Global Distribution

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 West Virginia, and southeast to Pennsylvania.

Best Places to See

• Lake Champlain (Clinton, Essex, Washington Counties)
• Cayuga Lake (Cayuga, Seneca, Tompkins Counties)
• Seneca Lake (Schuyler, Seneca, Yates Counties)

Identification Comments

General Description

Summer-stratified monomictic lakes are so deep (or large) that they have only one period of mixing or turnover each year (monomictic), and one period of stratification. These lakes generally do not freeze over in winter (except in unusually cold years), or form only a thin or sporadic ice cover during the coldest parts of midwinter, so the water circulates and is isothermal during the winter (similar temperature though the water column). These lakes are typically thermally stratified only in the summer (warmest water at the surface); they are oligotrophic to mesotrophic and alkaline.

Characters Most Useful for Identification

The dominant fishes include salmonids such as cisco (Coregonus artedii), and lake trout (Salvelinus namaycush) as well as yellow perch (Perca flavescens), rainbow smelt (Osmerus mordax), rock bass (Ambloplites rupestris), walleye (Stizostedion vitreum), brown bullhead (Ameiurus nebulosus), white sucker (Catostomus commersoni), and northern pike (Esox lucius). Characteristic invertebrates may include the mollusks eastern elliptio (Elliptio complanata), eastern lampmussel (Lampsilis radiata), pocketbook (L. ovata), pink heelsplitter (Potamilus alatus), floaters (Pyganodon cataracta, P. grandis), and mud amnicola (Amnicola limosa). Characteristic aquatic macrophytes include pondweeds (Potamogeton gramineus, P. richardsonii, P. pectinatus), horned pondweed (Zannichellia palustris), naiad (Najas flexilis), waterweed (Elodea canadensis), tapegrass or wild celery (Vallisneria americana), and coontail (Ceratophyllum demersum). A characteristic crustacean of the hypolimnion of Finger Lake examples is Senecella calanoides, which was named after Seneca Lake. Dominant invertebrates of the profundal zone of Lake Champlain are Spheriidae and the oligochaetes Stylodrilus heringianus and Peloscolex variegatus. Winter epilimnion plankton species assemblages are usually well developed. Characteristic plankton may include the following phytoplankton: Fragilaria spp. and Anabaena spp. in summer; Melosira spp. and Cryptomonas ovata in winter; and the following the zooplankton: Daphnia spp., and Diaptomus spp. in summer; Limnocalanus macrurus, and Cyclops bicuspidatus in winter.

Elevation Range

Known examples of this community have been found at elevations between -305 feet and 95 feet.

Best Time to See

Summer-stratified monomictic lakes can be easily observed from the shoreline where there is public access, or by boat during calm weather.

Summer-stratified Monomictic Lake Images

Southern Lake Champlain viewed from Mount Defiance.
Stephen M. Young

Southern Lake Champlain viewed from Mount Defiance.
Stephen M. Young

Summer-stratified monomictic lakes (Cayuga Lake and Seneca Lake)

Summer-stratified monomictic lake (Lake Champlain)

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Classification

Characteristic Species

Similar Ecological Communities

• Bog lake/pond (guide)
  Bog lake/pond: The aquatic community of a dystrophic lake (an acidic lake with brownish water that contains a high amount of organic matter) that typically occurs in a small, shallow basin (e.g., a kettehole) that is protected from wind and is poorly drained. These lakes occur in areas with non-calcareous bedrock or glacial till; many are fringed or surrounded by a floating mat of vegetation (in New York usually either bog or poor fen). Characteristic features of a dystrophic lake include the following: murky water that is stained brown, with low transparency; water that is low in plant nutrients (especially low in calcium), with naturally low pH (less than 5.4); and the lake may have oxygen deficiencies in deeper water (the profundal zone). The lack of calcium blocks bacterial action, reducing the rate of decay of organic matter with subsequent accumulation of peat or muck sediments. Colloidal and dissolved humus material reduces transparency and increases acidity of the water. Characteristic macrophytes include water-shield (Brasenia schreberi), fragrant white water lily (Nymphaea odorata), yellow pond-lily (Nuphar microphylla, and Nuphar variegata), bladderworts (Utricularia vulgaris, U. geminiscapa, U. purpurea), pondweeds (Potamogeton epihydrus, P. oakesianus), bur-reeds (Sparganium fluctuans, S. angustifolium), and clubrush (Scirpus subterminalis). Characteristic zooplankton may include the rotifers Keratella spp. and Brachionus spp. Summer-stratified monomictic lakes are so deep (or large) that they have only one period of mixing or turnover each year (monomictic), and one period of stratification. These lakes generally do not freeze over in winter (except in unusually cold years), or form only a thin or sporadic ice cover during the coldest parts of midwinter, so the water circulates and is isothermal during the winter (similar temperature though the water column). These lakes are typically thermally stratified only in the summer (warmest water at the surface); they are oligotrophic to mesotrophic and alkaline. Characteristic aquatic macrophytes include pondweeds (Potamogeton gramineus, P. richardsonii, P. pectinatus), horned pondweed (Zannichellia palustris), naiad (Najas flexilis), waterweed (Elodea canadensis), tapegrass or wild celery (Vallisneria americana), and coontail (Ceratophyllum demersum).
• Eutrophic dimictic lake (guide)
  Eutrophic dimictic lake: The aquatic community of a nutrient-rich lake that occurs in a broad, shallow basin. These lakes are dimictic: they have two periods of mixing or turnover (spring and fall); they are thermally stratified in the summer, and they freeze over and become inversely stratified in the winter. Aquatic macrophytes are abundant in shallow water, and there are many species present, but species diversity is generally lower than in mesotrophic lakes. Characteristic plants include tapegrass (Vallisneria americana), pondweeds (Potamogeton spp.), bur-reeds (Sparganium spp.), and the floating aquatic plants white water-lily (Nymphaea spp.), yellow pond-lily (Nuphar luteum), and water-shield (Brasenia schreberi). Characteristic features of a eutrophic lake include the following: yellow, green, or brownish-green water that is murky, with low transparency (Secchi disk depths typically less than 2.5 m, but up to 4 m in some cases); water rich in plant nutrients (especially high in phosphorus, nitrogen and calcium); high primary productivity (inorganic carbon fixed = 75 to 250 g/m2/yr); lake sediments that are rich in organic matter (usually consisting of a fine organic silt or copropel); water that is well-oxygenated above the summer thermocline, but oxygen-depleted below the summer thermocline or under ice; epilimnion volume that is relatively large compared with hypolimnion; and a weedy shoreline. Alkalinity is typically high (greater than 12.5 mg/l calcium carbonate). Summer-stratified monomictic lakes are so deep (or large) that they have only one period of mixing or turnover each year (monomictic), and one period of stratification. These lakes generally do not freeze over in winter (except in unusually cold years), or form only a thin or sporadic ice cover during the coldest parts of midwinter, so the water circulates and is isothermal during the winter (similar temperature though the water column). These lakes are typically thermally stratified only in the summer (warmest water at the surface); they are oligotrophic to mesotrophic and alkaline. Characteristic aquatic macrophytes include pondweeds (Potamogeton gramineus, P. richardsonii, P. pectinatus), horned pondweed (Zannichellia palustris), naiad (Najas flexilis), waterweed (Elodea canadensis), tapegrass or wild celery (Vallisneria americana), and coontail (Ceratophyllum demersum).
• Eutrophic pond (guide)
  Eutrophic ponds: The aquatic community of a small, shallow, nutrient-rich pond. Species diversity is typically high. Aquatic vegetation is abundant. Characteristic plants include coontail (Ceratophyllum demersum), duckweeds (Lemna minor, L. trisulca), waterweed (Elodea canadensis), pondweeds (Potamogeton spp.), water starwort (Heteranthera dubia), bladderworts (Utricularia spp.), naiad (Najas flexilis), tapegrass or wild celery (Vallisneria americana), algae (Cladophora spp.), common yellow pond-lily (Nuphar variegata), and white water-lily (Nymphaea odorata). The water is usually green with algae, and the bottom is mucky. Eutrophic ponds are too shallow to remain thermally stratified throughout the summer; they often freeze and become inversely stratified in the winter (coldest water at the surface), therefore they are winter-stratified monomictic ponds. Additional characteristic features of a eutrophic pond include the following: water that is murky, with low transparency (Secchi disk depths typically less than 4 m); water rich in plant nutrients (especially high in phosphorus, nitrogen, and calcium), high primary productivity (inorganic carbon fixed = 75 to 250 g/m2/yr) and a weedy shoreline. Alkalinity is typically high (greater than 12.5 mg/l calcium carbonate). Summer-stratified monomictic lakes are so deep (or large) that they have only one period of mixing or turnover each year (monomictic), and one period of stratification. These lakes generally do not freeze over in winter (except in unusually cold years), or form only a thin or sporadic ice cover during the coldest parts of midwinter, so the water circulates and is isothermal during the winter (similar temperature though the water column). These lakes are typically thermally stratified only in the summer (warmest water at the surface); they are oligotrophic to mesotrophic and alkaline. Characteristic aquatic macrophytes include pondweeds (Potamogeton gramineus, P. richardsonii, P. pectinatus), horned pondweed (Zannichellia palustris), naiad (Najas flexilis), waterweed (Elodea canadensis), tapegrass or wild celery (Vallisneria americana), and coontail (Ceratophyllum demersum).
• Great Lakes deepwater community (guide)
  Great Lakes deepwater community: The open water community in any of the Great Lakes. In general, the Great Lakes are summer-stratified monomictic lakes: they usually do not freeze over in winter, they are mixed and isothermal in winter, and thermally stratified in summer (warmest water at the surface). One exception is that portions of eastern Lake Erie, along the New York shores, freeze over quite frequently. These lakes are primarily mesotrophic with eutrophic nearshore areas. Specialized habitats include nearshore fluvial deposits, deepwater reefs and trenches. The Great Lakes are distinguished from inland summer-stratified monomictic lakes because of their size and access to estuarine biota through the St. Lawrence River and Welland Canal. Lake Champlain is similar to this lake type. However, it is classified as a summer-stratified monomictic lake. Summer-stratified monomictic lakes are so deep (or large) that they have only one period of mixing or turnover each year (monomictic), and one period of stratification. These lakes generally do not freeze over in winter (except in unusually cold years), or form only a thin or sporadic ice cover during the coldest parts of midwinter, so the water circulates and is isothermal during the winter (similar temperature though the water column). These lakes are typically thermally stratified only in the summer (warmest water at the surface); they are oligotrophic to mesotrophic and alkaline. Characteristic aquatic macrophytes include pondweeds (Potamogeton gramineus, P. richardsonii, P. pectinatus), horned pondweed (Zannichellia palustris), naiad (Najas flexilis), waterweed (Elodea canadensis), tapegrass or wild celery (Vallisneria americana), and coontail (Ceratophyllum demersum).
• Meromictic lake (guide)
  Meromictic lake: the aquatic community of a relatively deep lake with small surface area that is so protected from wind-stirring that it has no annual periods of complete mixing, and remains chemically stratified throughout the year. These lakes may be protected from mixing by a sheltered surrounding landscape (e.g., a deep basin) or by adjacent tree cover. Meromictic lakes in New York freeze over and become inversely stratified in the winter (coldest water at the surface); they pass through spring, and fall periods of isothermy without circulating. Meromictic lakes frequently have dichothermic stratification, meaning that the minimum temperature occurs in the middle stratum. The stagnant waters in the lower part of a meromictic lake become heavily loaded with dissolved salts, and lack oxygen. Chemical stratification is most often measured by salinity gradients, or total cation and anion concentrations. Gradients may be present for chemicals, such as hydrogen sulfide, ammonia, phosphorus, or iron. Flushing rates are typically low. Some examples of this lake type may be dystrophic, and thus resemble bog lakes. Species diversity is low because very few organisms can tolerate the extreme chemical conditions of the lower strata of a meromictic lake. Fishes are absent or sparse. Summer-stratified monomictic lakes are so deep (or large) that they have only one period of mixing or turnover each year (monomictic), and one period of stratification. These lakes generally do not freeze over in winter (except in unusually cold years), or form only a thin or sporadic ice cover during the coldest parts of midwinter, so the water circulates and is isothermal during the winter (similar temperature though the water column). These lakes are typically thermally stratified only in the summer (warmest water at the surface); they are oligotrophic to mesotrophic and alkaline. Characteristic aquatic macrophytes include pondweeds (Potamogeton gramineus, P. richardsonii, P. pectinatus), horned pondweed (Zannichellia palustris), naiad (Najas flexilis), waterweed (Elodea canadensis), tapegrass or wild celery (Vallisneria americana), and coontail (Ceratophyllum demersum).
• Mesotrophic dimictic lake (guide)
  Mesotrophic dimictic lake: The aquatic community of a lake that is intermediate between an oligotrophic lake and a eutrophic lake. These lakes are dimictic: they have two periods of mixing or turnover (spring and fall), they are thermally stratified in the summer (warmest water at the surface), and they freeze over and become inversely stratified in the winter (coldest water at the surface). These lakes typically have a diverse mixture of submerged macrophytes, such as several species of pondweeds (Potamogeton amplifolius, P. praelongus, P. robbinsii), water celery or tape grass (Vallisneria americana), and bladderworts (Utricularia spp.). Characteristic features of a mesotrophic lake include the following: water with medium transparency (Secchi disk depths of 2 to 4 m); water with moderate amounts of plant nutrients; moderate primary productivity (inorganic carbon fixed = 25 to 75 g/m2/yr); lake sediments with moderate amounts of organic matter; and moderately well-oxygenated water. Alkalinity is typically moderate (slightly greater than 12.5 mg/l calcium carbonate). Summer-stratified monomictic lakes are so deep (or large) that they have only one period of mixing or turnover each year (monomictic), and one period of stratification. These lakes generally do not freeze over in winter (except in unusually cold years), or form only a thin or sporadic ice cover during the coldest parts of midwinter, so the water circulates and is isothermal during the winter (similar temperature though the water column). These lakes are typically thermally stratified only in the summer (warmest water at the surface); they are oligotrophic to mesotrophic and alkaline. Characteristic aquatic macrophytes include pondweeds (Potamogeton gramineus, P. richardsonii, P. pectinatus), horned pondweed (Zannichellia palustris), naiad (Najas flexilis), waterweed (Elodea canadensis), tapegrass or wild celery (Vallisneria americana), and coontail (Ceratophyllum demersum).
• Oligotrophic dimictic lake (guide)
  Oligotrophic dimictic lake: The aquatic community of a nutrient-poor lake that often occurs in deep, steeply-banked basins. These lakes are dimictic, meaning they have two periods of mixing and turnover (spring and fall); they are stratified in the summer, then they freeze in winter and become inversely stratified. Common physical characteristics of oligotrophic lakes include blue or green highly transparent water (Secchi disk depths from 4 to 8 m), low dissolved nutrients (especially nitrogen and calcium), low primary productivity, and sediment with low levels of organic matter. Additionally, the lakes have an epilimnion volume that is low relative to the hypolimnion, high dissolved oxygen levels year-round through all strata, and low alkalinity. The plant community is primarily in the shallow parts of the lake, between 1 and 3 m (3 to 10 feet), and is dominated by rosette-leaved aquatic species. Characteristic species include seven-angle pipewort (Eriocaulon aquaticum), water lobelia (Lobelia dortmanna), quillworts (Isoetes echinospora ssp. muricata, I. lacustris), milfoils (Myriophyllum alterniflorum, M. tenellum), bladderworts (Utricularia purpuea, U. resupinata), tape grass (Vallisneria americana), and creeping buttercup (Ranunculus repens). Summer-stratified monomictic lakes are so deep (or large) that they have only one period of mixing or turnover each year (monomictic), and one period of stratification. These lakes generally do not freeze over in winter (except in unusually cold years), or form only a thin or sporadic ice cover during the coldest parts of midwinter, so the water circulates and is isothermal during the winter (similar temperature though the water column). These lakes are typically thermally stratified only in the summer (warmest water at the surface); they are oligotrophic to mesotrophic and alkaline. Characteristic aquatic macrophytes include pondweeds (Potamogeton gramineus, P. richardsonii, P. pectinatus), horned pondweed (Zannichellia palustris), naiad (Najas flexilis), waterweed (Elodea canadensis), tapegrass or wild celery (Vallisneria americana), and coontail (Ceratophyllum demersum).
• Oligotrophic pond (guide)
  Oligotrophic pond: The aquatic community of a small, shallow, nutrient-poor pond. The water is very clear, and the bottom is usually sandy or rocky. Aquatic vegetation is typically sparse, and species diversity is low. Characteristic species are rosette-leaved aquatics such as pipewort (Eriocaulon aquaticum), water lobelia (Lobelia dortmanna), and quillwort (Isoetes echinospora). Oligotrophic ponds are too shallow to remain thermally stratified throughout the summer; they often freeze and become inversely stratified in the winter (coldest water at the surface), therefore they are winter-stratified monomictic ponds. Additional characteristic features of an oligotrophic pond include the following: blue or green water with high transparency (Secchi disk depths of 4 to 8 m); water low in plant nutrients (especially low in nitrogen, also low in calcium); low primary productivity (inorganic carbon fixed = 7 to 25 g/m2/yr). Alkalinity is typically low (less than 12.5 mg/l calcium carbonate). Summer-stratified monomictic lakes are so deep (or large) that they have only one period of mixing or turnover each year (monomictic), and one period of stratification. These lakes generally do not freeze over in winter (except in unusually cold years), or form only a thin or sporadic ice cover during the coldest parts of midwinter, so the water circulates and is isothermal during the winter (similar temperature though the water column). These lakes are typically thermally stratified only in the summer (warmest water at the surface); they are oligotrophic to mesotrophic and alkaline. Characteristic aquatic macrophytes include pondweeds (Potamogeton gramineus, P. richardsonii, P. pectinatus), horned pondweed (Zannichellia palustris), naiad (Najas flexilis), waterweed (Elodea canadensis), tapegrass or wild celery (Vallisneria americana), and coontail (Ceratophyllum demersum).
• Winter-stratified monomictic lake (guide)
  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). They are eutrophic to mesotrophic. Littoral, and epilimnion species assemblages predominate. Pelagic species assemblages are well developed. 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. Summer-stratified monomictic lakes are so deep (or large) that they have only one period of mixing or turnover each year (monomictic), and one period of stratification. These lakes generally do not freeze over in winter (except in unusually cold years), or form only a thin or sporadic ice cover during the coldest parts of midwinter, so the water circulates and is isothermal during the winter (similar temperature though the water column). These lakes are typically thermally stratified only in the summer (warmest water at the surface); they are oligotrophic to mesotrophic and alkaline. Characteristic aquatic macrophytes include pondweeds (Potamogeton gramineus, P. richardsonii, P. pectinatus), horned pondweed (Zannichellia palustris), naiad (Najas flexilis), waterweed (Elodea canadensis), tapegrass or wild celery (Vallisneria americana), and coontail (Ceratophyllum demersum).

Additional Resources

References

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.

Cayuga Lake Watershed Network. 2017. Cayuga Lake Watershed Restoration and Protection Plan. Prepared for the Cayuga Lake Watershed Intermunicipal Organization by the Cayuga Lake Watershed Network, Aurora, 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/

Fiske, S. and R. Levey. 1995. Survey of native mussel-beds in Lake Champlain. Lake Champlain Basin Program, July 1995.

Genesee/Finger Lake Regional Planning Council. 2012. Seneca Lake Watershed Management Plan: Characterization and Subwatershed Evaluation. Genesee/Finger Lake Regional Planning Council, Rochester, NY.

Greeley, J.R. 1930. II. Fishes of the Lake Champlain watershed. pp. 44-87. in: A biological survey of the Lake Champlain watershed. E. Moore, editor. Supplemental to 19th annual report, New York State Conservation Department, 321 pp.

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.

Lake Champlain Basin Program (LCBP). 2017. Opportunities for Action: An Evolving Plan for the Future of the Lake Champlain Basin (OFA). Lake Champlain Basin Program, Grand Isle, VT.

Lake Champlain Basin Study. 1979. Limnology of Lake Champlain. U.S. Department of Commerce National Technical Information Service PB-295 612. January 1979. 407 pp.

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.

Links

• Adirondack Lakes Survey Corporation
• Adirondack Park Invasive Plant Program (APIPP) Aquatic Program Early Detection Reports
• Cayuga Lake Watershed Restoration and Protection Plan
• Lakes and Rivers (NYS DEC)
• New York State Federation of Lake Associations (NYSFOLA) Aquatic Invasive Species by County
• Northeast Lake and Pond Classification System (TNC)
• Opportunities for Action for Lake Champlain
• Seneca Lake Watershed Management Plan

About This Guide

This guide was authored by: Gregory J. Edinger

Information for this guide was last updated on: June 4, 2021

Please cite this page as:
New York Natural Heritage Program. 2023. Online Conservation Guide for Summer-stratified monomictic lake. Available from: https://guides.nynhp.org/summer-stratified-monomictic-lake/. Accessed March 31, 2023.