lakes I Flashcards
what are 4 functions of lakes?
- water storage
- fish food and biodiversity
- regulate river flows
- regulate climate
what is a lake? (hydrological definition and biological definition)
many different definitions
hydrological definition: a body of standing water deeper than 2 meters and larger than 2 ha
biological definition: a body of standing water with a littoral zone, a photic zone and a profundal zone
what are 5 origins of lakes?
- glacial/periglacial lake
- volcanic/crater lake
- rift/tectonic lake
- endorheic/aeolian lake
- lakes formed by river activity
what are 4 types of glacial lakes?
- ice-dammed lakes
- bedrock dammed lakes
- landslide-dammed lakes
- moraine-dammed lakes
what are thermokarst lakes?
forms when permafrost melts and creates surface depressions that fill with melted water
how is a graben valley created?
through tension cracks from tectonic movement and further crustal extension
what are 5 types of lakes formed by river activity?
- plunge-pool lakes (created by waterfalls)
- lateral lakes (tributaries dammed by river sediment)
- floodplain lakes (floodplain depressions)
- oxbow lakes (disconnected former meander loops)
- deltaic lakes (in river deltas, formed by sediment damming)
explain the succession of lakes
over long time scales, lakes disappear due to sediment deposition (influx of river sediments or accumulation of organic matter)
why is lake volume important? (7 reasons)
- residence time
- nutrients and pollutants
- carbon budget
- heat budget and mixing patterns
- weather and climate
- biological production
- biodiversity
what is bathymetry?
the measurement of water depth
how do we measure bathymetry in lakes?
with GIS by estimating from surrounding topography, surveys are too costly and time consuming
