Small lakes (<10Ac) with alkalinity of < 50 ppm and low pH.
The pH of this mineral-poor lake type is below neutral due to a lack of groundwater influence. Soft bog lakes typically have clear water and a firm substrate and support an oligotrophic submergent community sparsely populated by short aquatic macrophytes called isoetids. Dwarf water-milfoil (Myriophyllum tenellum), seven-angled pipe-wort (Eriocaulon aquaticum), and submersed brown-fruited rush (Juncus pelocarpus) are examples of the plant group commonly found in high-quality soft bog lakes. Bladderworts (Utricularia spp.) may be associated with shallow mineral pockets. Floating lilies (Nymphaea odorata and Nuphar variegata) can usually be found along lake margins, which transition to a narrow sphagnum lawn and fringe of sedges. This, in turn, often transitions to an open bog dominated by leather-leaf (Chamaedaphne calyculata), Labrador-tea (Rhododendron groenlandicum), black spruce (Picea mariana), and tamarack (Larix laricina). Because soft bog lakes are nutrient poor, they are particularly vulnerable to eutrophication. High nutrient levels can lead to dense beds of duckweeds (Lemna spp.) and water-meals (Wolfia spp.) as well as larger aquatic macrophytes like coon-tail (Ceratophyllum demersum) and common waterweed (Elodea canadensis), which can displace the smaller isoetids. Associated fish species include central mudminnow and yellow perch.
