New York Natural Heritage Program
Oligotrophic Dimictic Lake

Characteristic Species [-]
Floating-leaved aquatics
  • Seven-angle Pipewort (Eriocaulon aquaticum)
  • Iso?tes echinospora ssp. muricata
  • Water Lobelia (Lobelia dortmanna)
Submerged aquatics
  • Small Water-wort (Elatine minima)
  • Alternate-flowered Water Milfoil (Myriophyllum alterniflorum)
  • Slender Water-milfoil (Myriophyllum tenellum)
  • Grassy Pondweed (Potamogeton gramineus)
  • Clasping-leaf Pondweed (Potamogeton perfoliatus)
  • Flatleaf Pondweed (Potamogeton robbinsii)
  • Creeping Butter-cup (Ranunculus repens)
  • Eastern Purple Bladderwort (Utricularia purpurea)
  • Lavender Bladderwort (Utricularia resupinata)
  • Eel-grass (Vallisneria americana)
Similar Ecological Communities
  • Bog lake
    Bog lakes, like oligotrophic dimictic lakes, are low in nutrients, but they are dystrophic, and typically very small and shallow. Due to the low decomposition rates of bog lakes, there is a high level of organic matter (peat). Bog lakes have low dissolved oxygen levels, and flora and fauna species assemblages that are low in diversity. Unlike bog lakes, oligotrophic dimictic lakes can be large and deep, and they have highly transparent water, high dissolved oxygen throughout strata, low organic matter in the sediment, and a large diversity of fauna species.
  • Eutrophic dimictic lake
    Like oligotrophic dimictic lakes, eutrophic dimictic lakes have two cycles of mixing per year. However, the physical characteristics of these lakes differ greatly. Relative to oligotrophic dimictic lakes, eutrophic dimictic lakes have lower water transparency (Secchi disk depths from 2.5 to 4 m), higher levels of dissolved nutrients, greater primary productivity, greater amounts of organic matter in the sediment, lower dissolved oxygen levels, and higher alkalinity. The water of eutrophic dimictic lakes is murky, typically yellow, green, or brownish-green in color. Oligotrophic dimictic lakes have very clear water.
  • Mesotrophic dimictic lake
    Mesotrophic dimictic lakes have characteristics that are intermediate between oligotrophic and eutrophic dimictic lake communities. Like these other communities, they have two cycles of mixing per year. Relative to oligotrophic dimictic lakes, mesotrophic dimictic lakes have lower water transparency (Secchi disk depths from 2 to 4 m), greater levels of dissolved nutrients, greater primary productivity, greater amounts of organic matter in the sediment, lower dissolved oxygen levels, and higher alkalinity.
  • Summer-stratified monomictic lake
    Summer-stratified monomictic lakes have only one period of mixing per year, unlike dimictic lakes, which have two. Summer-stratified monomictic lakes are very large and/or deep, have high alkalinity, and can be oligotrophic to mesotrophic. They do not freeze completely during the winter, and therefore are isothermal during this time. They are usually thermally stratified only in the summer.
  • Winter-stratified monomictic lake
    Winter-stratified monomictic lakes have only one period of mixing per year, unlike dimictic lakes, which have two. Winter-stratified monomictic lakes have large surface areas relative to their depth, and are exposed to wind such that they are isothermic during the warm weather months. They do not stratify until winter, when they freeze. Winter-stratified monomictic lakes can be mesotrophic to eutrophic.
  • Meromictic lake
    Meromictic lakes typically have small surface areas relative to their depth. They are sheltered from wind such that they experience no mixing of strata, and thus remain stratified year-round. The lowest strata have low dissolved oxygen levels and high dissolved salts, creating harsh conditions for fauna. For this reason, species diversity is generally low. Oligotrophic dimictic lakes have two cycles of mixing per year, high dissolved oxygen throughout strata, and a large diversity of fauna species.
Vegetation
Floating-leaved aquatics
Submerged aquatics
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Percent Cover
This figure helps visualize the structure and 'look' or 'feel' of a typical Oligotrophic Dimictic 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%.