Term
| what is the definition of a river or stream |
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Definition
| an aquatic ecosystem characterized by unidirectional flow and represents the surficial movement of both ground and surface water across the landscape |
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Term
| what are three key differences between lakes and streams/rivers |
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Definition
1. lakes- stable ecosystems
rivers-dynamic ecosystems
2. lakes-big bowls of water
rivers- unpredictable
3. lakes- biologically controlled
rivers- physically controlled |
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Term
| understanding ____ processes is central to understanding streams and rivers |
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Definition
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Term
| what are 4 ways to characterize physical dynamics of streams |
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Definition
1. channel form
2. channel type
3. stream order
4. stream habitat |
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Term
| what are 2 types of channels used to characterize streams? describe them |
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Definition
1. intermintent stream (sometimes water, sometimes not)
2. perennial streams (flows year round) |
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Term
| how do you characterize a stream based on stream order? |
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Definition
| via strahlwer stream order 1 branch equals primay 1+1=2ndary 2+2=3iary 3+3=4th etc however 2+1=stays 2nd and 3+1= stays 3rd |
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Term
| what are 4 ways to characterize stream habitat? be able to describe them |
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Definition
1. water column
2. benthic zone (upper well oxiginated sediment layer)
3. hyporheic zone (mixing zone between stream and ground water zone)
4. floodplain (temporary habitat during floods) |
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Term
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Definition
-part of the physical structure of streams and rivers
-stream flow= "master variable' for ecological conditions in streams |
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Term
| what is hydrological discharge and how is it measured? |
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Definition
volume of water passing thru a channel cross section per unit time
Q=velocity*area
ex Q=m^3/s |
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Term
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Definition
| Q over time... reflects the amount of rainfall |
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Term
| what are 4 components of a hydrograph |
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Definition
1. baseflow
2. rising limb
3. falling limb
4. lag time |
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Term
| what are 2 chacteristics of streams involving temperature? |
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Definition
1. no thermal stratification (streams and rivers are well mixed)
2. greater variability in temp relative to lakes (variability affected by groundwater inputs and stream order) |
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Term
| what are 2 controls of streams involving light? |
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Definition
1. surrounding conditions (ie trees, canyons or banks)
2. water (ie depth suspended solids) |
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Term
| what are 3 chacteristics of streams involving water chemisty? |
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Definition
1. vertical stratification is extremely rare
2. DO is often high b/c big air/h2o interface and mixing due to turbulent water flow
3. exceptions including turbid or sewage treatment outflows
-nutrients influence by human activity |
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Term
| what are characteristics of stream biota? |
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Definition
1. life cycles simlar to those in lakes
-many insect orders found in both systems
2. biota must adapt to flow water (an important point!) |
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Term
| what are 3 adaptations to flowing water of stream invertebrates? |
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Definition
1. maintaining position (ex. suction cups)
2. feeding (filter feeders)
3. surviving extreme events
-utilize refugia (ex giant water bug crawls out of streams during heavy rainstorms)
-life history adaptations (resiliant lifestages during hard times)
-life history adaptations |
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Term
| how do fish species adapt to streams!? |
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Definition
| wide body shaps, razor back sucker (had a humped back which pushes it down) |
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Term
| what is the river continuum concept? (part of the longitudinal gradients section) |
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Definition
stream discharge increasees as moving down higher order
velocity increases at lower orders
different fish in different orders |
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