Lotic = moving water, constant current,
What are the differences between lentic and lotic
systems?
lotic- has current, moving, elevation change, has constant water
supply, can freeze, no layered regions, more oxygen
lentic- no current, nonmoving, land locked (maybe), layered
regions, greater biodeversity
How do rivers and streams form?
Elevation differences, runoff, amount of runoff depends on how
big your stream/river is you should have constant water supply
Discharge- the amount of water moving into another body of water
*organisms that are going to survive in a lotic environment have
to be able to deal with the current
Stream order
stream order refers to the size of the stream
stream order is based on tributaries, drainage area, total
length, age of water, and flow rate
order 1- smallest stream
order 15- highest stream
you need two of the same orders to move up to the next order. ex.
order 1 combines with another order 1 and it equals and order 2
,two order 2s equal and order 3
Intermittent streams- dries up occassionally
Age of water- you age water by the point it enters
stream or river, the further downstream the older the water
Current
the sides have the slowest movement due to friction (and
turbulent flow)
top has faster flowing area (still has friction with air)
middle is the fastest flowing area (no friction)
Two types of flow (current)
1.laminar flow- only occurs when water is moving slowly. all
liquid units progress in parallel lines with respect to eachother
2.turbulent flow- irregularity flows at different rates,
directions, and speeds at different places
Ways materials can be transported
Dissolved matter-matter that is dissolved into the water
suspended solids- solids that are carried in the current
*bed load- all the sediments that are carried down the river
Adaptions to the lotic environment
1. Behavioral- avoid strong
currents
get in back waters
bury yourself in sediments
boor right into the plants
2. Morphological- change body shape
hooks
streamline
holdfast
hump
sucking disks
roughened patch or pad
ballast
shell
What adaptations to the lotic environment does this trout
exhibit?
organic drift- a feature of
running water only changes throughout the day movement of
detritus down river happens more at night
Stream competence
the grain size that a current can barely move
depositing
aggrading- stream depositing its excess load greater than its
capacity (digging things out more)
degrading-picking up alluvium from the channel
classification of lotic animals
carnivores- pierces, and engulphers
grazers- scrappers and shredders
collectors (filler feeders)
River water is tested for?
all the same tests done for lentic systems plus:
fecal choliform
current (flow rate)
flow-volume
stream competence
turbidity
organic drift