lakes and reserves Flashcards
let 7
T/F: all lakes are permanent
no lakes can be perminant or intermittent depending on precipitation levels/seasonal variation
T/F: a lake is slowly moving, or not moving water and also it’s connected to the ocean
false lakes are NOT connected to the ocean
lakes can be formed by
glaciers, plate tectonics, dams, dormant volcanos, sinkholes, meteors and wind erosion
how do glaciers form lakes
- as it moves, it creates pockets in earth. all the leftover ice in those pockets = lake
how do plate tectonic form lakes
graben lakes = fault lines cause crust to drop = form depression (lake baikal)
horst lakes = block of crust tilts and leaves a depression
how do dams form lakes
blocking a stream or river by rock or debris can trap water
caused by beavers, land slides, lava crap…
3 lake habitats
- pelagic zone
- profundal zone
- littoral zone
which lake habitat areas most diversity
- most diversity in upper layers (pelagic and littoral) because more light
use a bathymetric map to tell you…
lake shape and size
what is retention time
Retention time = average length of time water stays in a lake
what’s shoreline development?
shoreline development: the longer the perimeter = the more shoreline development
lake laogai has a shoreline development = 1.0
what does this mean
it’s circular, most water in the lake isn’t touching the shore
lakes that are ____ and have ____ are more productive. explain
shallow and high shoreline development
shallow = more light grows plants, more mixing by wind
high shoreline = more nutrients seep into water
3 reservoir characteristics
- high shoreline development index
- shallow depth
- productive
why has sediment outputs to oceans decreased?
because the resevoirs are holding on to the sediment
resevoirs has very controlled outflow of water, therefore there can be ____ fluctuations in water levels
large
large fluctuations of water levels from a reservoir has the greatest effect on ____ communities
littoral
3 stratification layers
epilimnion
metalimnion
hypolimnion
monomictic vs dimictic stratification
mono stratification = once a year in the summer the lake stratifies, mixes and evenly dispersed during other times of year
di strat = stratifies twice a year (summer and winter), and mixes in spring and fall
amictic stratification means the lake is _________ and occurs where
always stratified (separated layers)
occurs in tropics or polar regions
polymictic stratification occurs ____ times a yer
many
T/F: stratification in lakes is caused by thermal gradient and no mixing
false because it can be different layers of thermal or salt gradients
+ no mixing ofc
wave height determined by ___ and ___-
wind strength
lake fetch
sciche waves only occur under these two conditions:
lake is stratified
wind is persistent
waves cause ___ and ____
mixing and shore erosion
