Full length freshwater exam 1

Morphometry

measurement of the shape of a water body

mountain streams are straight

flatland streams are curvy

Z =

depth

T sub w =

residence time

Index of Shoreline development (D sub L)

ratio of shoreline length to the circumference of a perfect circle of the same area

DL=1: perfect circle; the higher the number the more imperfect it is

What is the importance of knowing shoreline development index?

measure of habitat availability

shoreline is where terrestrial meets aquatic (littoral zone)

Sinuosity

measure of how much curvature a stream has

bendy rivers have high sinuosity

current velocity

speed of water flow (ft/ sec or m/sec)

Average at 6/10 depth

slowest along stream edges

stream gradient

vertical drop of stream channel

stream discharge

(Q)

water volume flowing over time

measurement of stream size

cross section x velocity

Thalweg

fastest flow bank to bank

generally the deepest point

wanders back and forth as river meanders or elevation changes

how do stream channels move?

through erosion and sedimentation

stream order

often used as opposed to stream discharge

estimate of size

what are the stream habitats

riffle/pool/run

snags

large natural wood and structures lodged in place

creates biodiversity

substrate size

Silt → Sand → Gravel → Pebbles → Cobble → Boulder → Bedrock

What determines substrate size?

velocity

overland flow

moves on within minutes

substrate flow

water that comes from other surfaces and eventually flows into the stream, this is the reason that the receding limb in the graph takes longer to go back down

What happens to the rising and receding limb of the graph when more urban development occurs

rising limb shoots up higher causing flash flooding but it doesnt take as long for the receding limb to decrease

decreases base flow

stream channel

section where water usually flows

stream bank

sometimes at edge of channel

bank full elevation

water is up but not considered a flood

channel forming discharge

the level that the channel starts to cut

alluvium

sediment transported and deposited by streams

aggradation

deposition of alluvium

degradation

erosion of sediment from stream channel

Q sub S

sediment size

T sub W

resonance time

D sub 50

median suspended particle size

Water vs. Air

temperature regulation (cold vs. warm blooded)

3D movement/Buoyancy

more stable water temp

viscosity (thickness of water)

hydration/salinity (regulation of water)

density/vibration

both are fluids

What is density

mass over volume (water is denser than air)

impact: more destructive/faster

What does ice limit in a lake

food, oxygen, and salinity

What properties does the shape of water affect?

hydrogen molecules are at 104.5 degrees

oxygen spends the most time with the electrons giving the molecule a slightly negative charge on that side and a slightly positive charge on the hydrogen side

Electrostriction

when ions make the water denser

What are some ways to meter

Secchi disk

light meter

Photosynthetically Active Radiation

any wavelengths that plants can use for photosynthesis

isothermal

water temperature is the same from top to bottom

epilimnion

the upper layer of water in a stratified lake

metalimnion

the middle layer of water in a stratified lake

hypolimnion

the lower layer of water in a stratified lake, typically cooler than the water above and relatively stagnant.

thermocline

a steep temperature gradient in a body of water such as a lake, marked by a layer above and below which the water is at different temperatures.

isopleths

lines of equal temperature and concentration

dimictic

stratifies twice per year, summer and winter, located in cooler climates

monomictic

stratifies once a year

cold monomictic

stratifies in winter

warm monomictic

stratifies in summer

amictic

never mixes due to ice cover

polymictic

mixes often, nearly daily

oligomictic

rarely mixes, once per decade or more

meromictic

contains a deep, dense layer that has high salinity and never mixes

orthograde

oxygen is saturated throughout

clinograde

DO is above saturation at the surface and there is little to no DO at the bottom

heterograde

peak DO is at an intermediate depth

photosynthetically active radiation (PAR)

light in wavelengths that plants can use

compensation depth

depth where there is just enough light for photosynthesis and photosynthesis is equal to respiration

euphotic zone

zone where there is enough light for photosynthesis

aphotic zone

zone where there isn’t enough light for photosynthesis

electrostriction

dense increases when ions are added

scattering

light is deflected by particles (dirt, algae)

light extinction coefficient

measures how strongly a substance absorbs and scatters light

1% level

the depth where 1% of the light reaching the waters surface can reach

trophogenic zone

where photosynthesis is greater than respiration

tropholytic zone

where photosynthesis is less than respiration

turnover

when stratified layers mix and nutrients are released

macrophytes

vascular plants

periphyton

attached algae

eutrophic

bodies of water with high productivity

oligotrophic

bodies of water with low productivity

mesotrophic

bodies of water with moderate productivity

eutrophication

the process of adding nutrients and increasing a water body's productivity

benthic zone

the muddy bottom of a lake, pond, or ocean where lots of bacteria and other decomposers and inverts live

littoral zone

where more than 1% of light reaches the bottom of the water

profundal zone

a region of water where sunlight does not reach

pelagic zone

water column

bathymetric maps

show depth and contour of water bodies

residence time

mean time water spends in a lake

sinuosity (P)

measure of how much curvature a stream has

lag time

time between peak of rain to peak of water flow

sediment load (Q sub S)

how much sediment is suspended

median suspended particle size (D sub 50)

average sediment size

alluvial plain

an area of fertile soil deposited by river floodwaters