EXAM 1 Flashcards
Characteristics of a lake
size based definitions: surface area, depth or zonation
Glacial lakes
74% of lakes, nutrient rich. formed from ice barriers or glacial erosion. Continental glaciers moved rocks and sediment to change the landscape.
Tectonic lakes
~5% of lakes. Often U or V shaped basins. Deep and unproductive. have GRABENS: flat bottom valleys produced by tectonic plate activity
Volcanogenic lakes
«1% of lakes. low nutrient concentrations and unproductive. deep usually old
Karst Regions
Lakes formed by soluable rocks (limestone or dolomite) that dissolves with acidic water. Small and unevenly distributed around the world
Riverine lakes
oxbow lakes: form when bends in a river become isolated due to errosive forces of rivers, usually shallow and oddly shaped
Floodplain lakes
form due to seasonal fluxes in water levels in a river basin
littoral zone
margin of lake to depth where no plants can grow
limnetic zone (palagic zone)
open water, no shore visible
benthic zone
bottom zone associated with sediments
profundal zone
deep region of the benthic, no light, fine sediments
limnetic zone
photic zone
profundal zone
aphotic zone
Epilimnion
top layer, warmer and lighter
Metamnion
medium temperature medium light
hypolimnion
dark, cold
meromictic lake
so deep that there is no single temperature, layer at the bottom never mixes
dimictic
2 mixing events per year