Nearctic Open Water - Code: Ne11D

Found throughout North America, Open Water is a habitat with few common threads. This habitat is generally more common in wetter areas though large reservoirs, water treatment plants, and other man made lakes and ponds are present throughout even hyper-arid areas of the continent. Open Water habitats can range in size from less than an acre to the massive Lake Superior (31,700 mi2 /82,100 km2). Often other types of freshwater wetlands occur along the shallower margins of Open Water. 
Some benthic, non-emergent, aquatic vegetation does grow in areas too deep for emergent vegetation but with enough light to promote plant growth. Depending on water clarity this zone is generally 3-12ft (1-4m) deep. Common aquatic plants include eelgrass (Vallisineria sp.), coontail (Ceratophyllum sp.), water milfoils (Myriophyllum sp.), and waterweeds (Elodea sp.). Many types of algae are also present in open water and green algae (Chlorophyta), red algae (Rhodophyta), blue-green algae (Cyanobacteria) and diatoms (Bacillariophyta are all integral parts of this habitat. 
Open Water can be generally divided into two useful groups – oligotrophic and eutrophic. Oligotrophic bodies of water are usually clear, with rocky or sandy bottoms, few nutrients, little algal growth and high oxygen content. Many high mountain lakes are oligotrophic and Lake Tahoe is a particularly famous example from the region – Lakes Michigan, Huron, and Superior are also considered oligotrophic. Eutrophic bodies of water by contrast are very biologically productive. They usually have soft, mucky bottoms, cloudy water, lots of aquatic plant and algal growth, and low oxygen content. Many Open Water areas will tend towards eutrophication over time as sediments accumulate and nutrients are deposited by run off. Rapid eutrophication is often the result of pollution as sewage, agricultural fertilizers and untreated waste water add massive amounts of phosphorous and nitrogen system. 
Rivers also share many characteristics with Open Water and have overlaps in ecology and wildlife. Slow Rivers tend toward being eutrophic while Fast Rivers are generally oligotrophic, though this varies with latitude and elevation as well.