Exam 1

Question 1

Steps of the Water Cycle

SHORT ANSWER

Answer 1

Evaporation: Occurs when warmth from the sun causes water from the ocean, lakes, streams, ponds, etc. to rise into the air and turn to vapor.
Condensation: when water vapor in the air cools (as it rises) and turns back into liquid which is stored in clouds.
Precipitation: water is released from the clouds in the form of rain, sleet, snow, or hail. It falls back to Earth’s surface.
When it falls to land, it can percolate through soil into ground water.
Transpiration: occurs when plants use water and CO2. Water is expelled from the leaves of plants and evaporates back into the atmosphere.

Question 2

Coal Mines

Answer 2

Acid mine drainage can damage rivers and streams making them a copper color and extremely acidic.
About a pH of 3.
Nothing can live in them.

Question 3

Properties of Water

ESSAY QUESTION

Answer 3

1. Essential for Life
2. Water molecules are polar.
3. Hydrogen bonding makes water cohesive.
4. Water is the universal solvent.
5. Water has stable temperature and tends to remain liquid.
6. Ice is less dense than liquid water, so it floats.
7. Water tends to dissociate into OH and H ions.

Question 4

Lake Stratification

Short Answer

Answer 4

Most temperate lentil habitats become stratifies during winter and summer. Lakes stratify into distinct layers.
In spring and fall, the change of temperatures and increased precipitation cause the water to mix and.
Layers:
Epilimnion - lighter water.
Thermocline is at the edge of the epilimnion and metalimnion - it is the area of max temperature change.
Metalimnion - layer of rapid temperature change - location of thermocline.
Hypolimnion - heavier water with lower oxygen, higher nutrients, and different pH and chemical concentration.
- Anything that dies during the summer, sinks.
- During the spring and fall, the lake flips and sends nutrients mixing throughout.

Question 5

Discharge

Answer 5

Measure in a riffle, not a deep pool.
The amount of water flowing through a cross sectional area.
Q = AV where A=area and V= current velocity (m/s).
Area = widthdepth (measured in meters)
Velocity depends on substrate, sinuosity (curviness), etc.
Discharge is measured in meters cubed/second or cfs.
Velocity needs to be below 200 for sampling.

Question 6

Laminar Vs. Turbulent Flow

Short Answer

Answer 6

Laminar flow - occurs closes to the surface of a solid object. It is smooth and constant.
Turbulent Flow - occurs above the surface of a solid object. Displayed by a chaotic collection of eddies and swirls. It exerts a shearing force that causes particles to move a long the bed (bedload).
The same shear stress causes eddies that entrain particles into suspension (suspended load). This looks like chocolate milk.
Suspended load also includes fines that are easily suspended (wash load). This always appears somewhat cloudy.
Many streams also have a dissolved load that is derived from chemical weathering.
- Ex: When water runs through limestone, it raises the pH and increases the hardness due to the presence of calcium carbonate.

Question 7

Bedload

Answer 7

When turbulent flow exerts a shearing force that causes particles to move along the bed.

Question 8

Suspended Load

Answer 8

The shearing stress also causes eddies that entrain fine sediment particles into suspension. 
It varies because of 
- rainfall, 
- steepness of slope, 
- intensity of land use.
It looks like chocolate milk.

Question 9

Wash Load

Answer 9

The suspended load includes fines that are also easily suspended and make up the wash load. This is the portion of sediment carried close to the free surface. This gives the “cloudy” appearance.

Question 10

Dissolved Load

Answer 10

This is materials, especially ions, derived from chemical weathering.
- Ex: When water runs through limestone, it raises the pH and increases the hardness due to the presence of calcium carbonate.

Question 11

Stream Total Energy

Answer 11

= Z (elevation) + D (depth) + V squared (velocity) / 2g (acceleration due to gravity.

Question 12

Manning’s Equation

Answer 12

Velocity of flow in a channel.
U = 1/nR^(2/3)S^(1/2)
R = hydraulic radius = mean depth
S = energy gradient = approximately the slope of water surface
n = Manning’s resistance coefficient.
- Roughness 9n) in plain streams = 0.03-0.07
- In floodplains = 0.05-0.15

Depth increases faster than slope.
This explains why velocity increases along stream’s length even if gradient decreases.
The more water you have the more discharge.

Question 13

Reynolds Number

Answer 13

Useful qualifier of biological fluid dynamics.
Re = UL/v
U = velocity
L = length
v = kinematic velocity (1.004 X 10^-6 m/s at 20 celcius.

Small organisms close to the substrate where velocity is low, have low Re values.
- At low Re, viscous forces dominated flow is laminar.
- Ex: mayfly (indicator of higher water quality)
Large organisms at greater velocity, have high Re values.
- At high Re, inertial forces dominate and turbulence occurs.

Question 14

Classes of Streams

Answer 14

Ephemeral - dry channel most of the year - only has water after rain.
Intermitten - dry channel part of the year - some groundwater flow.
Perennial - carry water year round - fed by stable groundwater.

Question 15

Sinuosity

Vocabulary

Answer 15

Is how curvy a river or creek is.
It is distance divided by the number of bends.
(draw picture)

Question 16

Hydrograph

Short Answer

Answer 16

It is a plot of discharge over time.
(Draw graph)
Curve will vary based on “flashiness” (big spikes associated with urbanization) or “sluggishness” (low gradient situations - ex: slope of the land).
- Often based on land use modifications.
- All streams are flashier than they were 100 years ago. This is from human impact like impervious surfaces and climate change.

Stage is often used as surrogate for discharge.
- Stage-discharge relationship = rating curve.

A hydrograph over time = hydrological cycle.

The base flow = average low flow conditions.
Lag = from the time it rains to the time that the water levels peak.

Question 17

Hydrological Cycle

Answer 17

Describes transport and storage of water.
- hydrograph over time = hydrological cycle.
Sources of water include:
- springs, wells, and rain water (most common).
Infiltration is the rate at which water enters the soil.
Surface flow happens when equilibrium of water in soil is reached.

Question 18

Infiltration

Answer 18

Rate at which water enters the soil.
Depends on (1) size and distance between soil particles, (2) attraction of water molecules to soil particles, and (3) attraction of water molecules to each other.
- Sandy soils are better for infiltration.
- Clay acts like a sponge.

Question 19

Hyporheic Zone

Answer 19

Under the substrate habitat.
Water under the substrate.
Ex: Arizona, Sycamore Creek, found madtoms, salamanders, and inverts.

Question 20

Watershed

Answer 20

Includes all the land draining a stream to a certain point.
drainage patterns determined by soils and geology.
- Ex: dendritic vs. distributary.
Dendritic = uniformed drainage pattern resembling the pattern made by branching trees.
Distributary = delta or alluvial fan. A stream that branches off and flows from a main stream channel.
- Ex: see as you approach the coast.

Question 21

Andrew Strahler

Answer 21

Came up with the system of stream order hierarchical classification.
- 86% of streams in U.S. are 1-3.
- MS river is 10th order.
- Two 1st orders trams make a 2nd order.
- Two 2nd order streams make a 3rd order, etc.
To change order, you need two of the same orders flowing into it.

Question 22

Characteristics of Stream Habitat (7)

Short Answer

Answer 22

More turbulent than lakes.
- Flow prevents stratification.
- High oxygen concentration.
Ice is less common.
- Ice is formed more easily in standing water.
More habitat heterogeneity.
Food web is more dependent on allochthonous production.
- (Energy comes from the outside) Ex: leaves.
More permanent on evolutionary and ecological time frame than lentil habitats.
- Most rivers and streams were formed during the Pleistocene. and are about 12,000 years old.
- Most reservoirs, ponds and lakes are relatively young.
Ex: Caddo lake is the only naturally occurring lake and it is only 900 years old.

Question 23

Benthic

Answer 23

Live on bottom

Question 24

Surface Flow

Answer 24

Occurs when equilibrium (soil can’t absorb any more water) is reached.

Question 25

Autochthonous

Answer 25

When energy is derived from inside the system and is dependent on the sun.
In lakes (lentic), phytoplankton make a lot of energy because there is more sunlight exposure.
Lotic systems are typically shaded by trees.

Question 26

Allochthonous

Answer 26

When energy is derived from outside the system.

In rivers and streams (lotic), leaves are a primary source of energy.

Question 27

What do organisms need?

Answer 27

• Place to live
• Food
• Suitable mates
• Place to mate
  They are all interdependent.

Question 28

Stream Mandering

Answer 28

When moving water in a stream erodes the outer banks and widens its valley, and the inner part of the river has less energy and deposits silt.
Characterized by erosion and deposition.
Can cause braiding with soft sediments.
- Ex: Red River in Oklahoma
Meandering over time leads to floodplain development.
Reservoirs tend to disconnect rivers from floodplains.
- Ex: It takes 10 miles for Niches to reconnect to floodplain below Lake Palestine.
Fallen trees and borders can exacerbate meandering.

Question 29

Alteration of River Systems

Answer 29

70% of discharge from the largest rivers in U.S., Europe, and Russia are affected by irrigation, diversion, or reservoirs.
2.5 Million dams in the U.S.
Reservoirs cause sédiments to settle upstream from rivers; rivers downstream become sediment “starved” and more erosive.
Armoring the banks causes more erosion.
Dams affect riparian habitats and affect aquatic organisms.
-Ex: Toledo Bend releases most water in August and January which alters the flood regime of the organisms that live there.
Dams exacerbate floods.

Question 30

Riparian Habitat

Answer 30

habitat located around a stream or river.

Ex: trees (water willows, caress), and floodplain.

Question 31

Poff and Ward

Short Answer

Answer 31

Flow is the most important physical attribute of streams. It affects habitat volume current velocity, channel geomorphology, substratum stability, etc.
78 Streams are classified by (1) flow variability, (2) flood regime pattern, and (3) extent of intermittency.
Classifications:
1. Harch Intermittent - long periods of zero flow and overall low flow; arid SW.
2. Intermitted flashy - high frequency of floods; arid SW.
3. Intermitted runoff - flood less frequently or predictably; central U.S.
4. Perennial flashy - high frequency of nonseasonal flooding; arid areas.
5. Perennial runoff - flood less grew. and less influenced by groundwater; heavily vegetated, mesic areas.
6. Winter rain - Pacific NW.
7. Mesic groundwater - most temporally.
- Caddo Indians settled near groundwater.
8. Snowmelt - flood predictably; Western Mountain streams.
9. Snow + rain - also western montane, but greater flood frequency.

• Most of East Texas streams are 5 or 7.

Question 32

Wiggins - Wetland Organism

Short Answer

Answer 32

Group 1: year-round residents incapable of active dispersal, avoid desiccation by burrowing into sediments during dry phases.
- Ex: Sea Monkeys and mollusks (copepods)
Group 2: spring residents; tolerant to drought and can actively disperse; oviposit in water but aestivate (air breathing) and over winter in dry basin.
- Ex: Insects
Group 3: summer recruits, oviposit in dry basin and over winter as eggs or larvae.
Group 4: non-wintering migrants, leave pool before dry phase and return in spring to breed. Inhabit temporary wetlands to reproduce in the food-rich and relatively predator free environment.
- EX: Tiger Salamander.

First colonizers are typically detritivores, which provide for later arriving predators.

Question 33

Succession

Answer 33

Change in community structure over time.

Question 34

Lake Classification

Answer 34

Oligotrophic - nutrient poor, clear in color, small phytoplankton population.
Mesotrophic - middle
Eutrophic - nutrient rich, turbid (brown), large phytoplankton population (green), low transparency.

Question 35

Transparency

Answer 35

Ability to see to the bottom.
Affected by suspended organic and inorganic particles.
Low transparency indicative of excessive turbidity (limits primary production) or high phytoplankton density.
Transparency is often measured with a light meter or Cecchi disk.
Color tell us much about ecosystem properties.

Question 36

Four Dimensions of Stream Networks

Answer 36

1. Longitudinal
2. Lateral
3. Vertical
4. Temporal

Question 37

Substrate
Importance
Contents
Types

Answer 37

1. Resting
2. Food acquisition
3. Reproduction and development
4. Refuge from predators and inhospitable environmental conditions

Contents - Minerals
(cobble, boulder, sand) and organic detritus.

Types:
Silt
Sand
Gravel
Cobble 
Boulder
Bedrock