Limnology Final
Terms
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- 4 degrees celcius
- highest density
- epilimnion
- warmer top layer of lake
- metalimnion
- part of thermocline where temperature decreases rapidly with depth
- hypolimnion
- lower, coldest layer of lake
- stratification caused by?
- density differences due to differing temperatures in lake that prevents mixing
- amictic lake
- doesn't mix (i.e. b/c frozen whole year)
- monomictic
- 1 period where lake mixes
- dimictic
- 2 periods when lake mixes
- what is inverse stratification?
- winter stratification where top is colder. Bottom water is about 4 degrees, which is denser & t/f sinks
- pelagic?
- open water
- allochthonous
- energy of photosynthetically-created compounds are from outside the lake
- cirque
- lakes formed by glaciers melting and erosion
- latent heat of melting
- energy in calories needed to melt 1g of substance (water)
- thalweg
- deepest part of a river channel eroded by meandering flow
- littoral zone
- Area in the lake that is photic and macrophytes occur
- seiche
- longstanding wave
- Arheic
- Water system where no rivers are formed (.e.g in desert areas)
- Overland flow
- Flow of water to lakes and basins that is above the soil's saturation point
- fetch
- distance of water that the wind blows across before it hits land
- heterotrophic
- organisms where respiration exceeds production
- graben
- lake formed from elongated depression created by downfaulting
- volcanic lakes
- cinder cones, maars, calderas
- What controls lake trophic condition?
- basin & lake shape b/c they determine photic level which determines productivity & succession of lake
- What determines clarity?
- Large depth: SA ratio
- interflow
- lateral flow that in the ground above groundwater
- water table
- level at which ground is completely saturated with water
- lake inputs
- precipitation, groundwater seepage, surface influents from streams + rivers/drainage basins
- lake output
- surface outlets (in lakes w/ clay + silt), groundwater seepage, evaporation, ET
- Exorheic
- Rivers originate + flow to sea
- Endorheic
- Rivers originate + never reach the sea
- humic
- material obtained from organic matter of soil
- light reaching lakes determined by
- time of day, latitude, season, absorption by O2, CO2; scattering; angle
- what determines type of stratification?
- latitude + altitude
- holomictic
- lakes that mix completely
- meromictic
- lakes that do not mix completely
- cold monomictic
- mixes in summer; frozen in winter
- warm monomictic
- water is stratified in summer; mixes in winter
- oligomictic
- rare circulation at irregular intervals
- after lower littoral
- littoriprofundal + profundal: bacteria rather than plant matter
- extinction coefficient
- large light extinction coefficient, photic zone is most shallow. Changes can be caused by algae, DOC, scatter from organic particulate/pollution
- why heating in first few meters of water?
- absorbance higher for longer wavelenth IR light, so first few meters catches most of it.
- Draw O2, CO2, pH curves
- sunrise lowest point O2
- Sequence for reduction of inorganic substances
- O2, NO3, Mn2+ formed, Fe3+ reduced to 2+, H2S formed from SO4, CH4 formed; O2, NO3, MnO2, Fe(OH)3, SO4 2-, CO2
- Difference sea water & freshwater
- freshwater: Low Cl, high Ca, Mg; high HCO3
- why ocean have diff. concentration than fresh water?
- evaporation increases concentration of Cl + SO4 in ocean. Ca lower b/c uptake by coral reef.
- apatite
- mineral containing P
- epipelic
- organisms grow on sediment
- mineralization
- also ammonification, where bacteria turn organic nitrogen compounds into NH4
- Nitrate reduction
- NO3- to NO2- to N2
- Nitrification
- NH4+ to NO3-