lecture #4 Flashcards
What four things do water movements effect?
Temperature
Biota
Distribution of dissolved gases and nutrients
Productivity
What is diffusion?
Is net movement of molecules from high conc areas to low conc areas, doesn’t involve actual movement of water
What is convection?
Is flow arising from density differences
What is advection?
is transport of a substance by the bulk movement of a fluid
What is laminar flow?
is low velocity of flow, flow path is mostly one directional
What is turbulent flow? What does it lead to?
Higher velocity, is disordered and leads to mixing
What are the three factors that affect flow types?
Velocity
Density
Viscosity
What makes water velocity slow? Where does this occur?
When it interacts with a surface, this happens at the bottom of a river, on rocks, on the shoreline of lakes
What is the flow boundary layer?
The outer edge of the region where water changes from laminar to turbulent
What effects the thickness of the boundary layer (increases it)?
decreased water velocity
increased roughness of the surface
increased distance from the upstream edge of an object
increased size
What organisms utilize this boundary layer? How does it support evolution?
algal mats
invertebrates
more hydrodynamic shapes occurs near the boundary layer
How long does it take for turbulent flow to occur?
At one year, large currents happen in 100s of years
What are waves?
rise and fall of water involving some oscillation
What are currents?
are the net unidirectional flow of water
Where do currents occur in a lake?
almost anywhere
Where do waves occur in a lake?
At the surface or at the thermocline
What contains most of the lakes energy?
currents
What is created faster in lakes, currents or waves?
waves
How does fetch increase wave height?
More fetch, means more wind hitting lake which means larger waves
What are surface seiches? What impacts this?
These happen in enclosed lakes where the whole body of water moves due to wind, fetch and size of lake impacts this
What are langmuir circulation cells?
These are currents in which there’s long lines parallel to wind direction but perpendicular to waves. Slow upwelling water and fast downwelling water create circulation and when they converge water flows downward, foam will accumulate at surface that can’t fall downwards including organisms.
In what types of winds are langmuir circulation cells created?
light winds
What causes Ekman spirals?
Wind and the coriolis effect
Where do Ekman spirals occur?
In large lakes and oceans
In the northern hemisphere how do ekman spirals move?
they move to the right of the wind
What are internal seiches?
These are the main source of deep water movement, they happen around the thermocline and cause it to shift which means there’s mixing between layers, can be caused by thermal stratification and wind
Can internal seiches be impacted coriolis?
yes
What is the biggest storage of water, list them?
Oceans, then continents, then polar ice
Where is the largest transport of water?
between atmosphere and oceans, then between atmosphere and continents, then between continents and ocean, and then between polar ice and ocean and polar ice and atmosphere
What is the vadose zone?
unsaturated
What is the capillary fringe?
area where groundwater is drawn up into pores by capillary action
What is the phreatic zone?
the saturated zone
What are the residence times of water ordered?
polar ice, then groundwater, then atmosphere, then land water
What are the three types of porosity? Describe them?
Intergranular- found in gravel and sand
Crevice- Foind in igneous rock
solution- found in limestone
What is the hyporheic zone?
Has a mix of ground water and river water
What are aquifers?
are underground formation of rock/solution where water accumulates and flows
Are wells a good measure for studying groundwater?
no amount of eukaryotes and prokaryotes differ greatly in wells versus aquifers
What an unconfined versus confined aquifer? How does this relate to artesian wells.
unconfined- doesn’t have an imperable layers on top restricitnf low, confined it does, causes water pressure so you can get well from it
