What is Blackwater river?
[[File:PostcardSuwaneeRiverFlorida.jpg|thumb|right|350px|The [[Suwanee River]]]] [[File:LeonSinksBlackWtrMay05.jpg|thumb|240px|right|A swamp-fed stream in northern Florida, showing tannin-stained undisturbed blackwater.]] A '''blackwater river''' is a river with a deep, slow-moving channel flowing through [[forest]]ed [[swamp]]s or [[wetland]]s. Its colour is caused by the [[decay]]ing [[vegetation]]. As vegetation decays, [[tannin]]s leach into the water, making a transparent, acidic water that is darkly stained, looking like tea or coffee. Most rivers in the [[Amazon Basin]] and the [[Southern United States]] are blackwater rivers. Not all dark rivers are blackwater in that technical sense. Some rivers in temperate regions, which drain or flow through areas of dark black soil, are black due to the color of the soil. These rivers are ''black mud rivers'' or estuaries. Blackwater rivers are lower in [[nutrients]] than [[Whitewater river (river type)|whitewater]] rivers and have [[Ion|ionic concentrations]] higher than rainwater.<ref>{{cite journal |doi=10.2307/2989823 |last=Janzen |first=D.H. |title=Tropical blackwater rivers, animals, and mast fruiting by the Dipterocarpaceae |url=https://archive.org/details/sim_biotropica_1974-07_6_2/page/69 |journal=Biotropica |volume=6 |issue=2 |date=July 1974 |pages=69–103 |jstor=2989823}}</ref><ref>{{cite journal |last=Sioli |first=Harald |year=1975 |title=Tropical rivers as expressions of their terrestrial environments |journal=Tropical Ecological Systems/Trends in Terrestrial and Aquatic Research |pages=275–288 |publisher=Springer Springer-Verlag |location=New York City}}</ref> The unique conditions lead to flora and fauna that differ both from whitewater and [[clearwater river]]s.<ref name=Duncan>Duncan W.P. & Fernandes M.N. 2010. Physicochemical characterization of the white, black, and clearwater rivers of the Amazon Basin and its implications on the distribution of freshwater stingrays (Chondrichthyes, Potamotrygonidae). ''PanamJAS'' '''5'''(3): 454-464.</ref><re